windows-server-2003/multimedia/opengl/server/soft/so_phong.c

/******************************Module*Header*******************************\
* Module Name: so_phong.c
*
* Routines to draw primitives
*
* Created: 10-16-1995
* Author: Hock San Lee [hockl]
*
* Copyright (c) 1995 Microsoft Corporation
\**************************************************************************/

#include "precomp.h"
#pragma hdrstop

#include <fixed.h>
#include <glmath.h>

#ifdef GL_WIN_phong_shading

#ifdef _X86_
#include <gli386.h>
#endif

#define __FASTEST

// Macros
#define DOT(m,a,b)      m = (a)->x*(b)->x + (a)->y*(b)->y + (a)->z*(b)->z
#define MAGN2(m,v)      DOT(m,v,v)

#if _X86_

#define SHADER  __GLcontext.polygon.shader

#define GET_HALF_AREA(gc, a, b, c)\
\
__asm{ mov     eax, a                                                                           };\
__asm{ mov     ecx, c                                                                           };\
__asm{ mov     ebx, b                                                                           };\
__asm{ mov     edx, gc                                                                          };\
__asm{ fld     DWORD PTR [OFFSET(__GLvertex.window.x)][eax]                                     };\
__asm{ fsub    DWORD PTR [OFFSET(__GLvertex.window.x)][ecx]      /* dxAC                     */ };\
__asm{ fld     DWORD PTR [OFFSET(__GLvertex.window.y)][ebx]                                     };\
__asm{ fsub    DWORD PTR [OFFSET(__GLvertex.window.y)][ecx]      /* dyBC dxAC                */ };\
__asm{ fld     DWORD PTR [OFFSET(__GLvertex.window.x)][ebx]                                     };\
__asm{ fsub    DWORD PTR [OFFSET(__GLvertex.window.x)][ecx]      /* dxBC dyBC dxAC           */ };\
__asm{ fld     DWORD PTR [OFFSET(__GLvertex.window.y)][eax]                                     };\
__asm{ fsub    DWORD PTR [OFFSET(__GLvertex.window.y)][ecx]      /* dyAC dxBC dyBC dxAC      */ };\
__asm{ fxch    ST(2)                                             /* dyBC dxBC dyAC dxAC      */ };\
__asm{ fst     DWORD PTR [OFFSET(SHADER.dyBC)][edx]                                             };\
__asm{ fmul    ST, ST(3)                                         /* dxACdyBC dxBC dyAC dxAC  */ };\
__asm{ fxch    ST(2)                                             /* dyAC dxBC dxACdyBC dxAC  */ };\
__asm{ fst     DWORD PTR [OFFSET(SHADER.dyAC)][edx]                                             };\
__asm{ fmul    ST, ST(1)                                         /* dxBCdyAC dxBC dxACdyBC dxAC */};\
__asm{ fxch    ST(1)                                             /* dxBC dxBCdyAC dxACdyBC dxAC */};\
__asm{ fstp    DWORD PTR [OFFSET(SHADER.dxBC)][edx]              /* dxBCdyAC dxACdyBC dxAC   */ };\
__asm{ fsubp   ST(1), ST                                /* +1*/  /* area dxAC                */ };\
__asm{ fxch    ST(1)                                             /* dxAC area                */ };\
__asm{ fstp    DWORD PTR [OFFSET(SHADER.dxAC)][edx]              /* area                     */ };\
__asm{ fstp    DWORD PTR [OFFSET(SHADER.area)][edx]     /* +1*/  /* (empty)                  */ };

#define STORE_AREA_PARAMS   

#else

#define GET_HALF_AREA(gc, a, b, c)\
    /* Compute signed half-area of the triangle */                  \
    dxAC = a->window.x - c->window.x;                               \
    dxBC = b->window.x - c->window.x;                               \
    dyAC = a->window.y - c->window.y;                               \
    dyBC = b->window.y - c->window.y;                               \
    gc->polygon.shader.area = dxAC * dyBC - dxBC * dyAC;

#define STORE_AREA_PARAMS\
    gc->polygon.shader.dxAC = dxAC;                                 \
    gc->polygon.shader.dxBC = dxBC;                                 \
    gc->polygon.shader.dyAC = dyAC;                                 \
    gc->polygon.shader.dyBC = dyBC;    

#endif


#if 0
#define ACCUM_MAT_CHANGE(dst,src) \
    if ((src)->dirtyBits & __GL_MATERIAL_AMBIENT)                           \
        (dst).ambient = (src)->ambient;                                     \
    if ((src)->dirtyBits & __GL_MATERIAL_DIFFUSE)                           \
        (dst).diffuse = (src)->diffuse;                                     \
    if ((src)->dirtyBits & __GL_MATERIAL_SPECULAR)                          \
        (dst).specular = (src)->specular;                                   \
    if ((src)->dirtyBits & __GL_MATERIAL_EMISSIVE)                          \
        (dst).emissive = (src)->emissive;                                   \
    if ((src)->dirtyBits & __GL_MATERIAL_SHININESS)                         \
        (dst).shininess = (src)->shininess;                                 \
    if ((src)->dirtyBits & __GL_MATERIAL_COLORINDEXES)                      \
    {                                                                      \
        (dst).cmapa = (src)->cmapa;                                         \ 
        (dst).cmapd = (src)->cmapd;                                         \
        (dst).cmaps = (src)->cmaps;                                         \
    }                                                                      \
    (dst).dirtyBits |= (src)->dirtyBits;                                   
#endif

#define SORT_AND_CULL_FACE(a, b, c, face, ccw)\
                                                                            \
    /*                                                                      \
    ** Sort vertices in y.  Keep track if a reversal of the winding         \
    ** occurs in direction (0 means no reversal, 1 means reversal).         \
    ** Save old vertex pointers in case we end up not doing a fill.         \
    */                                                                      \
    reversed = 0;                                                           \
    if (__GL_VERTEX_COMPARE(a->window.y, <, b->window.y)) {                 \
        if (__GL_VERTEX_COMPARE(b->window.y, <, c->window.y)) {             \
            /* Already sorted */                                            \
        } else {                                                            \
            if (__GL_VERTEX_COMPARE(a->window.y, <, c->window.y)) {         \
                temp=b; b=c; c=temp;                                        \
                reversed = 1;                                               \
            } else {                                                        \
                temp=a; a=c; c=b; b=temp;                                   \
            }                                                               \
        }                                                                   \
    } else {                                                                \
        if (__GL_VERTEX_COMPARE(b->window.y, <, c->window.y)) {             \
            if (__GL_VERTEX_COMPARE(a->window.y, <, c->window.y)) {         \
                temp=a; a=b; b=temp;                                        \
                reversed = 1;                                               \
            } else {                                                        \
                temp=a; a=b; b=c; c=temp;                                   \
            }                                                               \
        } else {                                                            \
            temp=a; a=c; c=temp;                                            \
            reversed = 1;                                                   \
        }                                                                   \
    }                                                                       \
                                                                            \
    GET_HALF_AREA(gc, a, b, c);                                             \
    ccw = !__GL_FLOAT_LTZ(gc->polygon.shader.area);                         \
                                                                            \
    /*                                                                      \
    ** Figure out if face is culled or not.  The face check needs to be     \
    ** based on the vertex winding before sorting.  This code uses the      \
    ** reversed flag to invert the sense of ccw - an xor accomplishes       \
    ** this conversion without an if test.                                  \
    **                                                                      \
    **      ccw reversed        xor                                         \
    **      --- --------        ---                                         \
    **      0   0           0 (remain !ccw)                                 \
    **      1   0           1 (remain ccw)                                  \
    **      0   1           1 (become ccw)                                  \
    **      1   1           0 (become cw)                                   \
    */                                                                      \
    face = gc->polygon.face[ccw ^ reversed];                                \
    if (face == gc->polygon.cullFace) {                                     \
    /* Culled */                                                            \
    return;                                                                 \
    }                                                                       \
                                                                            \
    STORE_AREA_PARAMS;                                                      


//*************** Local functions *******************
void SnapXLeft(__GLcontext *gc, __GLfloat xLeft, __GLfloat dxdyLeft);
void SnapXRight(__GLshade *sh, __GLfloat xRight, __GLfloat dxdyRight);

void InitLineParamsVan (__GLcontext *gc, __GLvertex *v0, __GLvertex *v1,
                        __GLfloat invDelta);
void InitLineParamsAccel (__GLcontext *gc, __GLvertex *v0, __GLvertex *v1,
                         __GLfloat invDelta);

static void SetInitialPhongParameters(__GLcontext *gc, __GLvertex *a,
                                      __GLcoord *an, __GLcolor *ac, 
                                      __GLfloat aFog,
                                      __GLfloat dx, __GLfloat dy);

void FASTCALL FillPhongSubTriangle(__GLcontext *gc, GLint iyBottom, 
                                     GLint iyTop);

void InitSpanInterpolationAccel (__GLcontext *gc);
void InitSpanNEInterpolationVan (__GLcontext *gc);
void InitSpanNInterpolationVan (__GLcontext *gc);

void UpdateParamsAlongSpanAccel (__GLcontext *gc);                    
void UpdateNAlongSpanVan (__GLcontext *gc);
void UpdateNEAlongSpanVan (__GLcontext *gc);

void ComputeRGBColorVanZippy (__GLcontext *gc, __GLcolor *outColor); 
void ComputeRGBColorVanFast  (__GLcontext *gc, __GLcolor *outColor); 
void ComputeRGBColorVanSlow  (__GLcontext *gc, __GLcolor *outColor);

void ComputeRGBColorAccelZippy (__GLcontext *gc, __GLcolor *outColor);
void ComputeRGBColorAccelFast  (__GLcontext *gc, __GLcolor *outColor);
// Not implemented yet. This is to accelerate Slow Lights
void ComputeRGBColorAccelSlow  (__GLcontext *gc, __GLcolor *outColor);


// No Zippy versions for CI color
// since there is no Color material for CI
void ComputeCIColorVanFast (__GLcontext *gc, __GLcolor *outColor);   
void ComputeCIColorVanSlow  (__GLcontext *gc, __GLcolor *outColor);

void ComputeCIColorAccelFast (__GLcontext *gc, __GLcolor *outColor);

void ComputePhongInvarientRGBColor (__GLcontext *gc);              

void __glCalcForwardDifferences( GLint w, __GLfloat p0, __GLfloat p1,
                              __GLfloat p2, __GLfloat *d1, __GLfloat *d2 );
#ifdef GL_WIN_specular_fog
__GLfloat ComputeSpecValue (__GLcontext *gc, __GLvertex *vx);
#endif //GL_WIN_specular_fog

/********************* Code **************************************/
#ifdef GL_WIN_specular_fog
__GLfloat ComputeSpecValue (__GLcontext *gc, __GLvertex *vx)
{
    __GLfloat nxi, nyi, nzi;
    __GLfloat zero;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLmaterialMachine *msm;
    GLboolean eyeWIsZero, localViewer;
    static __GLcoord Pe = { 0, 0, 0, 1 };
    __GLcoord n, e;
    __GLfloat fog = 0;
    __GLfloat msm_threshold, msm_scale, *msm_specTable;

    zero = __glZero;

    n = vx->normal;
    e.x = vx->eyeX;
    e.y = vx->eyeY;
    e.z = vx->eyeZ;
    e.w = vx->eyeW;
    
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    msm = &gc->light.front;
    nxi = n.x;
    nyi = n.y;
    nzi = n.z;

    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;

    localViewer = gc->state.light.model.localViewer;

    eyeWIsZero = __GL_FLOAT_EQZ(vx->eyeW);
    
    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        __GLfloat n1, n2;
            
        lss = lsm->state;
        lspmm = &lsm->front;
            
        if (lsm->slowPath || eyeWIsZero)
        {
            __GLcoord hHat, vPli, vPliHat, vPeHat;
            __GLfloat att, attSpot;
            __GLfloat hv[3];
                
            /* Compute unit h[i] */
            __glVecSub4(&vPli, &e, &lsm->position);
            __glNormalize(&vPliHat.x, &vPli.x);
            if (localViewer)
            {
                __glVecSub4(&vPeHat, &e, &Pe);
                __glNormalize(&vPeHat.x, &vPeHat.x);
                hv[0] = vPliHat.x + vPeHat.x;
                hv[1] = vPliHat.y + vPeHat.y;
                hv[2] = vPliHat.z + vPeHat.z;
            }
            else
            {
                hv[0] = vPliHat.x;
                hv[1] = vPliHat.y;
                hv[2] = vPliHat.z + __glOne;
            }
            __glNormalize(&hHat.x, hv);
                
            /* Compute attenuation */
            if (__GL_FLOAT_NEZ(lsm->position.w))
            {
                __GLfloat k0, k1, k2, dist;
                    
                k0 = lsm->constantAttenuation;
                k1 = lsm->linearAttenuation;
                k2 = lsm->quadraticAttenuation;
                if (__GL_FLOAT_EQZ(k1) && __GL_FLOAT_EQZ(k2))
                {
                    /* Use pre-computed 1/k0 */
                    att = lsm->attenuation;
                }
                else
                {
                    __GLfloat den;

                    dist = __GL_SQRTF(vPli.x*vPli.x + vPli.y*vPli.y
                                      + vPli.z*vPli.z);
                    den = k0 + k1 * dist + k2 * dist * dist;
                    att = __GL_FLOAT_EQZ(den) ? __glOne : __glOne / den;
                }
            }
            else
            {
                att = __glOne;
            }
                
            /* Compute spot effect if light is a spot light */
            attSpot = att;
            if (lsm->isSpot)
            {
                __GLfloat dot, px, py, pz;
                    
                px = -vPliHat.x;
                py = -vPliHat.y;
                pz = -vPliHat.z;
                dot = px * lsm->direction.x + py * lsm->direction.y
                      + pz * lsm->direction.z;
                if ((dot >= lsm->threshold) && (dot >= lsm->cosCutOffAngle))
                {
                    GLint ix = (GLint)((dot - lsm->threshold) * lsm->scale 
                                       + __glHalf);
                    if (ix < __GL_SPOT_LOOKUP_TABLE_SIZE)
                        attSpot = att * lsm->spotTable[ix];
                }
                else
                {
                    attSpot = zero;
                }
            }
                
            /* Add in remaining effect of light, if any */
            if (attSpot)
            {
                __GLfloat n1, n2;
                __GLcolor sum;
                    
                n1 = nxi * vPliHat.x + nyi * vPliHat.y + nzi * vPliHat.z;
                if (__GL_FLOAT_GTZ(n1))
                {
                    n2 = nxi * hHat.x + nyi * hHat.y + nzi * hHat.z;
                    n2 -= msm_threshold;
                    if (__GL_FLOAT_GEZ(n2))
                    {
                        __GLfloat fx = n2 * msm_scale + __glHalf;
                        if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                            n2 = msm_specTable[(GLint)fx];
                        else
                            n2 = __glOne;
                        fog += n2;
                    }
                }
            }
        }
        else
        {
            __GLfloat n1, n2;
                
            /* Add in specular and diffuse effect of light, if any */
            n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
                 nzi * lsm->unitVPpli.z;
            if (__GL_FLOAT_GTZ(n1))
            {
                n2= nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * lsm->hHat.z;
                n2 -= msm_threshold;
                if (__GL_FLOAT_GEZ(n2)) 
                {
                    __GLfloat fx = n2 * msm_scale + __glHalf;
                    if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                        n2 = msm_specTable[(GLint)fx];
                    else
                        n2 = __glOne;
                    fog += n2;
                }
            }
        }
    }
        
    fog = 1.0 - fog;
    if (__GL_FLOAT_LTZ (fog)) fog = __glZero;
    return fog;
}
#endif //GL_WIN_specular_fog

static void AccumMatChange (__GLmatChange *dst, __GLmatChange *src)
{
    if (src->dirtyBits & __GL_MATERIAL_AMBIENT)                          
        dst->ambient = src->ambient;                                     
 
   if (src->dirtyBits & __GL_MATERIAL_DIFFUSE)                 
        dst->diffuse = src->diffuse;                           
    if (src->dirtyBits & __GL_MATERIAL_SPECULAR)                
        dst->specular = src->specular;                         
    if (src->dirtyBits & __GL_MATERIAL_EMISSIVE)                
        dst->emissive = src->emissive;                         
    if (src->dirtyBits & __GL_MATERIAL_SHININESS)               
        dst->shininess = src->shininess;                       
    if (src->dirtyBits & __GL_MATERIAL_COLORINDEXES)            
    {                                                                     
        dst->cmapa = src->cmapa;                                       
        dst->cmapd = src->cmapd;                                       
        dst->cmaps = src->cmaps;                                       
    }                                                                     
    dst->dirtyBits |= src->dirtyBits;                                   
}

// Propagate the valid Normals through the vertex buffer.
//
// IN:  color, normal (front)
// OUT: color, normal (front) (all vertices are updated)

void FASTCALL PolyArrayPhongPropagateColorNormal(__GLcontext *gc, 
                                                 POLYARRAY *pa)
{
    POLYDATA *pd;
    POLYDATA *pdLast;
    GLuint paNeeds;
    GLboolean doFrontColor, doBackColor;
    POLYMATERIAL  *pm;
    __GLphongMaterialData *pmdata = NULL;
    
    
    paNeeds = gc->vertex.paNeeds;
    doFrontColor = paNeeds & PANEEDS_FRONT_COLOR;
    doBackColor  = paNeeds & PANEEDS_BACK_COLOR;

    if (gc->polygon.shader.phong.flags & __GL_PHONG_NEED_EYE_XPOLATE)
        ASSERTOPENGL(pa->flags & POLYARRAY_EYE_PROCESSED, 
                     "Eye coordinate should be available now\n");
    
    // If color is not needed, fill in the colors field 
    // with default.
    
    if (paNeeds & PANEEDS_SKIP_LIGHTING)
    {
        /////?????????!!!!!!!!!!! Look again!!!
        if (doFrontColor) (*gc->procs.paCalcColorSkip)(gc, pa, 0);
        if (doBackColor) (*gc->procs.paCalcColorSkip)(gc, pa, 1);
        return ;
    }


    pdLast = pa->pdNextVertex-1;

    // Check is there are any glMaterial calls that were made 
    // immediately after glBegin, the ones made after the first
    // glVertex call are ignored.

    if (pa->flags & (POLYARRAY_MATERIAL_BACK | POLYARRAY_MATERIAL_BACK))
    {
        pm = GLTEB_CLTPOLYMATERIAL();

        //DbgPrint ("Has the costly material change\n");
        pmdata = (__GLphongMaterialData *)
            GCALLOC(gc, sizeof(__GLphongMaterialData));
        if (pmdata == NULL)
        {
            return;
        }

        pmdata->flags = 0;
        pmdata->matChange[__GL_PHONG_FRONT_FIRST].dirtyBits = 0;
        pmdata->matChange[__GL_PHONG_BACK_FIRST].dirtyBits = 0;
        pmdata->matChange[__GL_PHONG_FRONT_TRAIL].dirtyBits = 0;
        pmdata->matChange[__GL_PHONG_BACK_TRAIL].dirtyBits = 0;

        if (pa->pd0->flags & POLYARRAY_MATERIAL_BACK)
        {
            AccumMatChange (&(pmdata->matChange[__GL_PHONG_BACK_FIRST]),
                            *(&pm->pdMaterial0[pa->pd0 - pa->pdBuffer0].front
                              +1));
            pmdata->flags |= __GL_PHONG_BACK_FIRST_VALID;
        }
        
        if (pa->pd0->flags & POLYARRAY_MATERIAL_FRONT)
        {
            AccumMatChange (&(pmdata->matChange[__GL_PHONG_FRONT_FIRST]),
                            *(&pm->pdMaterial0[pa->pd0 - pa->pdBuffer0].front));
            pmdata->flags |= __GL_PHONG_FRONT_FIRST_VALID;
        }

        // Accumulate the remaining material changes to be applied later
        for (pd = pa->pd0 + 1; pd <= pdLast; pd++)
        {
            if (pd->flags & POLYARRAY_MATERIAL_BACK)
            {
                AccumMatChange (&(pmdata->matChange[__GL_PHONG_BACK_TRAIL]),
                                *(&pm->pdMaterial0[pd - pa->pdBuffer0].front+1));
                pmdata->flags |= __GL_PHONG_BACK_TRAIL_VALID;
            }
            
            if (pd->flags & POLYARRAY_MATERIAL_FRONT)
            {
                AccumMatChange (&(pmdata->matChange[__GL_PHONG_FRONT_TRAIL]), 
                                *(&pm->pdMaterial0[pd - pa->pdBuffer0].front));
                pmdata->flags |= __GL_PHONG_FRONT_TRAIL_VALID;
            }
            
        }
        pa->phong = pmdata;
        pa->flags |= POLYARRAY_PHONG_DATA_VALID;
    }
    

    for (pd = pa->pd0; pd <= pdLast; pd++)
    {
        if (gc->state.enables.general & __GL_COLOR_MATERIAL_ENABLE)
        {
            if (!(pd->flags & POLYDATA_COLOR_VALID))
            {
                // If color has not changed for this vertex, 
                // use the previously computed color.
                
                ASSERTOPENGL(pd != pa->pd0, "no initial color\n");
                if (gc->modes.colorIndexMode)
                {
                    pd->colors[0].r = (pd-1)->colors[0].r;
                }
                else
                {
                    pd->colors[0].r = (pd-1)->colors[0].r;
                    pd->colors[0].g = (pd-1)->colors[0].g;
                    pd->colors[0].b = (pd-1)->colors[0].b;
                    pd->colors[0].a = (pd-1)->colors[0].a;
                }
                pd->flags |= POLYDATA_COLOR_VALID;
            }
            else if (pa->flags & POLYARRAY_CLAMP_COLOR) 
            {
                if (gc->modes.colorIndexMode)
                {
                    __GL_CLAMP_CI(pd->colors[0].r, gc, pd->colors[0].r);
                }
                else
                {
                    __GL_CLAMP_R(pd->colors[0].r, gc, pd->colors[0].r);
                    __GL_CLAMP_G(pd->colors[0].g, gc, pd->colors[0].g);
                    __GL_CLAMP_B(pd->colors[0].b, gc, pd->colors[0].b);
                    __GL_CLAMP_A(pd->colors[0].a, gc, pd->colors[0].a);
                }
            }
        }
        
        if (!(pd->flags & POLYDATA_NORMAL_VALID))
        {
            // If the normal has not changed for this vertex, 
            // use the previously computed normal.
            ASSERTOPENGL(pd != pa->pd0, "no initial normal\n");
            pd->normal = (pd-1)->normal;
            pd->flags |= POLYDATA_NORMAL_VALID;
        }
        else
        {
            if (gc->vertex.paNeeds & PANEEDS_NORMAL) 
            {
                (*gc->mInv->xf3)(&pd->normal, &pd->normal.x, gc->mInv);
                if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
                    __glNormalize(&pd->normal.x, &pd->normal.x);
            }
        }
    } 

    gc->vertex.paNeeds &= ~PANEEDS_NORMAL;
    pa->flags &= ~POLYARRAY_MATERIAL_FRONT;
    pa->flags &= ~POLYARRAY_MATERIAL_BACK;
    pa->flags &= ~POLYARRAY_SAME_COLOR_DATA;

}


void FASTCALL 
__glRenderPhongTriangle(__GLcontext *gc, __GLvertex *a, 
                        __GLvertex *b, __GLvertex *c)
{
    GLuint needs, modeFlags;
    GLint ccw, colorFace, reversed, face;
    __GLfloat dxAC, dxBC, dyAC, dyBC;
    __GLvertex *temp;
    
#ifdef NO_RENDERING
    return;
#endif
    
    //Assert that Lighting is on for Phong-shading to take place
    ASSERTOPENGL(gc->state.enables.general & __GL_LIGHTING_ENABLE,
                 "No lighting. Should be smooth-shaded\n");
    
    SORT_AND_CULL_FACE(a, b, c, face, ccw);
    
    if (__GL_FLOAT_EQZ(gc->polygon.shader.area))
        return;
    /*
    ** Pick face to use for coloring
    */
    modeFlags = gc->polygon.shader.modeFlags;
    if (modeFlags & __GL_SHADE_TWOSIDED && face == __GL_BACKFACE)
    {
        gc->polygon.shader.phong.face = __GL_BACKFACE; 
    }
    else
    {
        gc->polygon.shader.phong.face = __GL_FRONTFACE; 
    }
    
    (*gc->procs.fillTriangle) (gc, a, b, c, (GLboolean) ccw);;
}




void FASTCALL 
__glFillPhongTriangle(__GLcontext *gc, __GLvertex *a, __GLvertex *b, 
                      __GLvertex *c, GLboolean ccw)
{
    __GLfloat oneOverArea, t1, t2, t3, t4;
    __GLfloat dxAC, dxBC, dyAC, dyBC;
    __GLfloat aFog, bFog;
    __GLfloat dxAB, dyAB;
    __GLfloat dx, dy, dxdyLeft, dxdyRight;
    __GLcolor *ac, *bc;
    __GLcoord *an, *bn;
    __GLcoord ae, be, ce;
    GLint aIY, bIY, cIY;
    GLuint modeFlags;
    __GLfloat dxdyAC;
    __GLcoord dnAC, dnBC, *cn;
    __GLcoord deAC, deBC;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    GLuint flags = 0, msm_colorMaterialChange;
    GLboolean needColor;

    //CHOP_ROUND_ON();
    FPU_SAVE_MODE ();
    FPU_CHOP_ON ();
    
    /* Pre-compute one over polygon area */

    __GL_FLOAT_BEGIN_DIVIDE(__glOne, gc->polygon.shader.area, &oneOverArea);

    modeFlags = gc->polygon.shader.modeFlags;

    if (gc->polygon.shader.phong.face == __GL_FRONTFACE)
        msm_colorMaterialChange = gc->light.front.colorMaterialChange;
    else
        msm_colorMaterialChange = gc->light.back.colorMaterialChange;

    if ((gc->state.enables.general & __GL_COLOR_MATERIAL_ENABLE) &&
        msm_colorMaterialChange && (modeFlags & __GL_SHADE_RGB)) 
    {
        flags |= __GL_PHONG_NEED_COLOR_XPOLATE;
        needColor = GL_TRUE;
    }
    
    //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    //!!! Compute Invariant color if possible !!!!!!!!
    //!!!    Use Otto's optimizations here    !!!!!!!!
    //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    if (((!(flags & __GL_PHONG_NEED_COLOR_XPOLATE) || 
        !(msm_colorMaterialChange & (__GL_MATERIAL_AMBIENT | 
                                     __GL_MATERIAL_EMISSIVE))) &&
        (modeFlags & __GL_SHADE_RGB)) &&
        !(phong->flags & __GL_PHONG_NEED_EYE_XPOLATE))
    {
        ComputePhongInvarientRGBColor (gc);
        flags |= __GL_PHONG_INV_COLOR_VALID;
    }
    
    //Store the flags
    phong->flags |= flags;


    /* Fetch some stuff we are going to reuse */
    modeFlags = gc->polygon.shader.modeFlags;
    dxAC = gc->polygon.shader.dxAC;
    dxBC = gc->polygon.shader.dxBC;
    dyAC = gc->polygon.shader.dyAC;
    dyBC = gc->polygon.shader.dyBC;
    ac = a->color;
    bc = b->color;
    an = &(a->normal);
    bn = &(b->normal);
    ae.x = a->eyeX; ae.y = a->eyeY; ae.z = a->eyeZ; ae.w = a->eyeW;
    be.x = b->eyeX; be.y = b->eyeY; be.z = b->eyeZ; be.w = b->eyeW;
    
    /*
    ** Compute delta values for unit changes in x or y for each
    ** parameter.
    */

    __GL_FLOAT_SIMPLE_END_DIVIDE(oneOverArea);
    t1 = dyAC * oneOverArea;
    t2 = dyBC * oneOverArea;
    t3 = dxAC * oneOverArea;
    t4 = dxBC * oneOverArea;
    
    /* Normals */
    cn = &(c->normal);
    dnAC.x = an->x - cn->x;
    dnAC.y = an->y - cn->y;
    dnAC.z = an->z - cn->z;

    dnBC.x = bn->x - cn->x;
    dnBC.y = bn->y - cn->y;
    dnBC.z = bn->z - cn->z;

    gc->polygon.shader.phong.dndx.x = dnAC.x * t2 - dnBC.x * t1;
    gc->polygon.shader.phong.dndy.x = dnBC.x * t3 - dnAC.x * t4;
    gc->polygon.shader.phong.dndx.y = dnAC.y * t2 - dnBC.y * t1;
    gc->polygon.shader.phong.dndy.y = dnBC.y * t3 - dnAC.y * t4;
    gc->polygon.shader.phong.dndx.z = dnAC.z * t2 - dnBC.z * t1;
    gc->polygon.shader.phong.dndy.z = dnBC.z * t3 - dnAC.z * t4;

    if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        ce.x = c->eyeX; ce.y = c->eyeY; ce.z = c->eyeZ; ce.w = c->eyeW;

        deAC.x = ae.x - ce.x;
        deAC.y = ae.y - ce.y;
        deAC.z = ae.z - ce.z;
        deAC.w = ae.w - ce.w;

        deBC.x = be.x - ce.x;
        deBC.y = be.y - ce.y;
        deBC.z = be.z - ce.z;
        deBC.w = be.w - ce.w;

        gc->polygon.shader.phong.dedx.x = deAC.x * t2 - deBC.x * t1;
        gc->polygon.shader.phong.dedy.x = deBC.x * t3 - deAC.x * t4;
        gc->polygon.shader.phong.dedx.y = deAC.y * t2 - deBC.y * t1;
        gc->polygon.shader.phong.dedy.y = deBC.y * t3 - deAC.y * t4;
        gc->polygon.shader.phong.dedx.z = deAC.z * t2 - deBC.z * t1;
        gc->polygon.shader.phong.dedy.z = deBC.z * t3 - deAC.z * t4;
        gc->polygon.shader.phong.dedx.w = deAC.w * t2 - deBC.w * t1;
        gc->polygon.shader.phong.dedy.w = deBC.w * t3 - deAC.w * t4;
    }
    
    if (modeFlags & __GL_SHADE_RGB) 
    {
        __GLfloat drAC, dgAC, dbAC, daAC;
        __GLfloat drBC, dgBC, dbBC, daBC;
        __GLcolor *cc;
        
        /* Colors */
        if (needColor)
        {
            cc = c->color;
            drAC = ac->r - cc->r;
            drBC = bc->r - cc->r;
            dgAC = ac->g - cc->g;
            dgBC = bc->g - cc->g;
            dbAC = ac->b - cc->b;
            dbBC = bc->b - cc->b;
            daAC = ac->a - cc->a;
            daBC = bc->a - cc->a;
        
        
            gc->polygon.shader.drdx = drAC * t2 - drBC * t1;
            gc->polygon.shader.drdy = drBC * t3 - drAC * t4;
            gc->polygon.shader.dgdx = dgAC * t2 - dgBC * t1;
            gc->polygon.shader.dgdy = dgBC * t3 - dgAC * t4;
            gc->polygon.shader.dbdx = dbAC * t2 - dbBC * t1;
            gc->polygon.shader.dbdy = dbBC * t3 - dbAC * t4;
            gc->polygon.shader.dadx = daAC * t2 - daBC * t1;
            gc->polygon.shader.dady = daBC * t3 - daAC * t4;
        }

        if (modeFlags & __GL_SHADE_TEXTURE) 
        {
            __GLfloat awinv, bwinv, cwinv, scwinv, tcwinv, qwcwinv;
            __GLfloat dsAC, dsBC, dtAC, dtBC, dqwAC, dqwBC;

            awinv = a->window.w;
            bwinv = b->window.w;
            cwinv = c->window.w;
            scwinv = c->texture.x * cwinv;
            tcwinv = c->texture.y * cwinv;
            qwcwinv = c->texture.w * cwinv;

            dsAC = a->texture.x * awinv - scwinv;
            dsBC = b->texture.x * bwinv - scwinv;
            dtAC = a->texture.y * awinv - tcwinv;
            dtBC = b->texture.y * bwinv - tcwinv;
            dqwAC = a->texture.w * awinv - qwcwinv;
            dqwBC = b->texture.w * bwinv - qwcwinv;

            gc->polygon.shader.dsdx = dsAC * t2 - dsBC * t1;
            gc->polygon.shader.dsdy = dsBC * t3 - dsAC * t4;
            gc->polygon.shader.dtdx = dtAC * t2 - dtBC * t1;
            gc->polygon.shader.dtdy = dtBC * t3 - dtAC * t4;
            gc->polygon.shader.dqwdx = dqwAC * t2 - dqwBC * t1;
            gc->polygon.shader.dqwdy = dqwBC * t3 - dqwAC * t4;
        }
    } 

    if (modeFlags & __GL_SHADE_DEPTH_ITER) 
    {
        __GLfloat dzAC, dzBC;

        dzAC = a->window.z - c->window.z;
        dzBC = b->window.z - c->window.z;
        
        gc->polygon.shader.dzdxf = dzAC * t2 - dzBC * t1;
        gc->polygon.shader.dzdyf = dzBC * t3 - dzAC * t4;
        if(( gc->modes.depthBits == 16 ) &&
           ( gc->depthBuffer.scale <= (GLuint)0xffff )) {
            gc->polygon.shader.dzdx = 
              FLT_TO_Z16_SCALE(gc->polygon.shader.dzdxf);
        }
        else {
            gc->polygon.shader.dzdx = FTOL(gc->polygon.shader.dzdxf);
        }
    }

#ifdef GL_WIN_specular_fog
    if (gc->polygon.shader.modeFlags & __GL_SHADE_COMPUTE_FOG)
    {
        __GLfloat dfAC, dfBC, cFog;

        /* Use eyeZ for interpolation value */
        aFog = a->eyeZ;
        bFog = b->eyeZ;
        cFog = c->eyeZ;

        dfAC = aFog - cFog;
        dfBC = bFog - cFog;

        gc->polygon.shader.dfdx = dfAC * t2 - dfBC * t1;
        gc->polygon.shader.dfdy = dfBC * t3 - dfAC * t4;
    } 
    else if (gc->polygon.shader.modeFlags & __GL_SHADE_INTERP_FOG)
    {
        __GLfloat dfAC, dfBC, cFog;
        
        aFog = bFog = cFog = 1.0f;
        
        if (gc->polygon.shader.modeFlags & __GL_SHADE_SPEC_FOG)
        {
            aFog = ComputeSpecValue (gc, a);
            bFog = ComputeSpecValue (gc, b);
            cFog = ComputeSpecValue (gc, c);
        }

        if (gc->polygon.shader.modeFlags & __GL_SHADE_SLOW_FOG)
        {
            aFog *= a->fog;
            bFog *= b->fog;
            cFog *= c->fog;
        }
        
        dfAC = aFog - cFog;
        dfBC = bFog - cFog;

        gc->polygon.shader.dfdx = dfAC * t2 - dfBC * t1;
        gc->polygon.shader.dfdy = dfBC * t3 - dfAC * t4;
    }
#else  //GL_WIN_specular_fog
    if (modeFlags & __GL_SHADE_COMPUTE_FOG)
    {
        __GLfloat dfAC, dfBC, cFog;

        /* Use eyeZ for interpolation value */
        aFog = a->eyeZ;
        bFog = b->eyeZ;
        cFog = c->eyeZ;

        dfAC = aFog - cFog;
        dfBC = bFog - cFog;

        gc->polygon.shader.dfdx = dfAC * t2 - dfBC * t1;
        gc->polygon.shader.dfdy = dfBC * t3 - dfAC * t4;
    }
    else if (modeFlags & __GL_SHADE_INTERP_FOG)
    {
        /* Use fog for interpolation value */
        aFog = a->fog;
        bFog = b->fog;
        cFog = c->fog;

        dfAC = aFog - cFog;
        dfBC = bFog - cFog;

        gc->polygon.shader.dfdx = dfAC * t2 - dfBC * t1;
        gc->polygon.shader.dfdy = dfBC * t3 - dfAC * t4;
    } 
#endif //GL_WIN_specular_fog
    
    __GL_FLOAT_SIMPLE_BEGIN_DIVIDE(dxAC, dyAC, dxdyAC);
    
    /* Snap each y coordinate to its pixel center */
    aIY = __GL_VERTEX_FIXED_TO_INT(__GL_VERTEX_FLOAT_TO_FIXED(a->window.y)+
                                   __GL_VERTEX_FRAC_HALF);
    bIY = __GL_VERTEX_FIXED_TO_INT(__GL_VERTEX_FLOAT_TO_FIXED(b->window.y)+
                                   __GL_VERTEX_FRAC_HALF);
    cIY = __GL_VERTEX_FIXED_TO_INT(__GL_VERTEX_FLOAT_TO_FIXED(c->window.y)+
                                   __GL_VERTEX_FRAC_HALF);

#ifdef __DBG_PRINT
    DbgPrint ("aIY=%d, bIY=%d, cIY=%d\n", aIY, bIY, cIY);
#endif
    
    /*
    ** This algorithim always fills from bottom to top, left to right.
    ** Because of this, ccw triangles are inherently faster because
    ** the parameter values need not be recomputed.
    */
    dxAB = a->window.x - b->window.x;
    dyAB = a->window.y - b->window.y;
    if (ccw) {
        dy = (aIY + __glHalf) - a->window.y;
        __GL_FLOAT_SIMPLE_END_DIVIDE(dxdyAC);
        SnapXLeft(gc, a->window.x + dy*dxdyAC, dxdyAC);
        dx = (gc->polygon.shader.ixLeft + __glHalf) - a->window.x;
        SetInitialPhongParameters(gc, a, an, ac, aFog, dx, dy);
        if (aIY != bIY) {
            dxdyRight = dxAB / dyAB;
            SnapXRight(&gc->polygon.shader, a->window.x + dy*dxdyRight,
                       dxdyRight);
#ifdef __DBG_PRINT
            DbgPrint ("dxdyRight = %f\n", dxdyRight);
#endif
            FillPhongSubTriangle(gc, aIY, bIY);
        }

        if (bIY != cIY) {
            dxdyRight = dxBC / dyBC;
            dy = (bIY + __glHalf) - b->window.y;
            SnapXRight(&gc->polygon.shader, b->window.x + dy*dxdyRight,
                       dxdyRight);
#ifdef __DBG_PRINT
            DbgPrint ("dxdyRight = %f\n", dxdyRight);
#endif
            FillPhongSubTriangle(gc, bIY, cIY);
        }
    } else {
        dy = (aIY + __glHalf) - a->window.y;
        __GL_FLOAT_SIMPLE_END_DIVIDE(dxdyAC);
        SnapXRight(&gc->polygon.shader, a->window.x + dy*dxdyAC, dxdyAC);
#ifdef __DBG_PRINT
        DbgPrint ("dxdyRight = %f\n", dxdyAC);
#endif
        if (aIY != bIY) {
            dxdyLeft = dxAB / dyAB;
            SnapXLeft(gc, a->window.x + dy*dxdyLeft, dxdyLeft);
            dx = (gc->polygon.shader.ixLeft + __glHalf) - a->window.x;
            SetInitialPhongParameters(gc, a, an, ac, aFog, dx, dy);
            FillPhongSubTriangle(gc, aIY, bIY);
        }

        if (bIY != cIY) {
            dxdyLeft = dxBC / dyBC;
            dy = (bIY + __glHalf) - b->window.y;
            SnapXLeft(gc, b->window.x + dy*dxdyLeft, dxdyLeft);
            dx = (gc->polygon.shader.ixLeft + __glHalf) - b->window.x;
            SetInitialPhongParameters(gc, b, bn, bc, bFog, dx, dy);
            FillPhongSubTriangle(gc, bIY, cIY);
        }
    }
    
    FPU_RESTORE_MODE();  // CHOP_ROUND_OFF();
}



static void SetInitialPhongParameters(__GLcontext *gc, __GLvertex *a,
                                      __GLcoord *an, __GLcolor *ac, 
                                      __GLfloat aFog, __GLfloat dx, 
                                      __GLfloat dy)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLshade *sh = &gc->polygon.shader;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    __GLfloat little = sh->dxLeftLittle;
    __GLfloat big = sh->dxLeftBig;
    GLuint modeFlags = sh->modeFlags;
    GLboolean needColor = (gc->polygon.shader.phong.flags & 
                               __GL_PHONG_NEED_COLOR_XPOLATE);

#define bPolygonOffset \
        (gc->state.enables.general & __GL_POLYGON_OFFSET_FILL_ENABLE )


     /* Set parameters for the shader */ 
    phong->nCur.x = an->x + dx*phong->dndx.x + dy*phong->dndy.x;
    phong->nCur.y = an->y + dx*phong->dndx.y + dy*phong->dndy.y;
    phong->nCur.z = an->z + dx*phong->dndx.z + dy*phong->dndy.z;

    phong->nLittle.x = phong->dndy.x + little * phong->dndx.x;
    phong->nLittle.y = phong->dndy.y + little * phong->dndx.y;
    phong->nLittle.z = phong->dndy.z + little * phong->dndx.z;

    if (big > little) 
    {
        phong->nBig.x = phong->nLittle.x + phong->dndx.x;
        phong->nBig.y = phong->nLittle.y + phong->dndx.y;
        phong->nBig.z = phong->nLittle.z + phong->dndx.z;
    }
    else
    {
        phong->nBig.x = phong->nLittle.x - phong->dndx.x;
        phong->nBig.y = phong->nLittle.y - phong->dndx.y;
        phong->nBig.z = phong->nLittle.z - phong->dndx.z;
    }

    if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        phong->eCur.x = a->eyeX + dx*phong->dedx.x + dy*phong->dedy.x;
        phong->eCur.y = a->eyeY + dx*phong->dedx.y + dy*phong->dedy.y;
        phong->eCur.z = a->eyeZ + dx*phong->dedx.z + dy*phong->dedy.z;
        phong->eCur.w = a->eyeW + dx*phong->dedx.w + dy*phong->dedy.w;

        phong->eLittle.x = phong->dedy.x + little * phong->dedx.x;
        phong->eLittle.y = phong->dedy.y + little * phong->dedx.y;
        phong->eLittle.z = phong->dedy.z + little * phong->dedx.z;
        phong->eLittle.w = phong->dedy.w + little * phong->dedx.w;

        if (big > little) 
        {
            phong->eBig.x = phong->eLittle.x + phong->dedx.x;
            phong->eBig.y = phong->eLittle.y + phong->dedx.y;
            phong->eBig.z = phong->eLittle.z + phong->dedx.z;
            phong->eBig.w = phong->eLittle.w + phong->dedx.w;
        }
        else
        {
            phong->eBig.x = phong->eLittle.x - phong->dedx.x;
            phong->eBig.y = phong->eLittle.y - phong->dedx.y;
            phong->eBig.z = phong->eLittle.z - phong->dedx.z;
            phong->eBig.w = phong->eLittle.w - phong->dedx.w;
        }
    }
        
    if (big > little) 
    {
        if (modeFlags & __GL_SHADE_RGB) 
        {
            if (needColor)
            {
                
                sh->frag.color.r = ac->r + dx*sh->drdx + dy*sh->drdy;

                sh->rLittle = sh->drdy + little * sh->drdx;
                sh->rBig = sh->rLittle + sh->drdx;
            
                sh->frag.color.g = ac->g + dx*sh->dgdx + dy*sh->dgdy;
                sh->gLittle = sh->dgdy + little * sh->dgdx;
                sh->gBig = sh->gLittle + sh->dgdx;
            
                sh->frag.color.b = ac->b + dx*sh->dbdx + dy*sh->dbdy;
                sh->bLittle = sh->dbdy + little * sh->dbdx;
                sh->bBig = sh->bLittle + sh->dbdx;
                
                sh->frag.color.a = ac->a + dx*sh->dadx + dy*sh->dady;
                sh->aLittle = sh->dady + little * sh->dadx;
                sh->aBig =sh->aLittle + sh->dadx;
            }
            if (modeFlags & __GL_SHADE_TEXTURE) 
            {
                __GLfloat oneOverW = a->window.w;
                sh->frag.s = a->texture.x * oneOverW + dx*sh->dsdx
                  + dy*sh->dsdy;
                sh->sLittle = sh->dsdy + little * sh->dsdx;
                sh->sBig = sh->sLittle + sh->dsdx;
                
                sh->frag.t = a->texture.y * oneOverW + dx*sh->dtdx
                  + dy*sh->dtdy;
                sh->tLittle = sh->dtdy + little * sh->dtdx;
                sh->tBig = sh->tLittle + sh->dtdx;
                
                sh->frag.qw = a->texture.w * oneOverW + dx*sh->dqwdx
                  + dy*sh->dqwdy;
                sh->qwLittle = sh->dqwdy + little * sh->dqwdx;
                sh->qwBig = sh->qwLittle + sh->dqwdx;
            }
        } 

        if (modeFlags & __GL_SHADE_DEPTH_ITER) 
        {
            __GLfloat zLittle, zOffset;

            zOffset = bPolygonOffset ? __glPolygonOffsetZ(gc) : 0.0f;
            if (gc->modes.depthBits == 16) 
            {
                sh->frag.z = (__GLzValue)
                FLT_TO_Z16_SCALE(a->window.z + dx*sh->dzdxf + dy*sh->dzdyf
                                 + zOffset );
                zLittle = sh->dzdyf + little * sh->dzdxf;
                sh->zLittle = FLT_TO_Z16_SCALE(zLittle);
                sh->zBig = FLT_TO_Z16_SCALE(zLittle + sh->dzdxf);
            }
            else 
            {
                sh->frag.z = (__GLzValue)
                  FTOL(a->window.z + dx*sh->dzdxf + dy*sh->dzdyf +
                       zOffset );
                zLittle = sh->dzdyf + little * sh->dzdxf;
                sh->zLittle = FTOL(zLittle);
                sh->zBig = FTOL(zLittle + sh->dzdxf);
            }
        }

        if (modeFlags & (__GL_SHADE_COMPUTE_FOG | __GL_SHADE_INTERP_FOG))
        {
            sh->frag.f = aFog + dx*sh->dfdx + dy*sh->dfdy;
            sh->fLittle = sh->dfdy + little * sh->dfdx;
            sh->fBig = sh->fLittle + sh->dfdx;
        }
    } 
    else 
    {    
        if (modeFlags & __GL_SHADE_RGB) 
        {
            if (needColor)
            {
                sh->frag.color.r = ac->r + dx*sh->drdx + dy*sh->drdy;
                sh->rLittle = sh->drdy + little * sh->drdx;
                sh->rBig = sh->rLittle - sh->drdx;

                sh->frag.color.g = ac->g + dx*sh->dgdx + dy*sh->dgdy;
                sh->gLittle = sh->dgdy + little * sh->dgdx;
                sh->gBig = sh->gLittle - sh->dgdx;
                
                sh->frag.color.b = ac->b + dx*sh->dbdx + dy*sh->dbdy;
                sh->bLittle = sh->dbdy + little * sh->dbdx;
                sh->bBig = sh->bLittle - sh->dbdx;
                
                sh->frag.color.a = ac->a + dx*sh->dadx + dy*sh->dady;
                sh->aLittle = sh->dady + little * sh->dadx;
                sh->aBig =sh->aLittle - sh->dadx;
            }
            if (modeFlags & __GL_SHADE_TEXTURE) 
            {
                __GLfloat oneOverW = a->window.w;
                sh->frag.s = a->texture.x * oneOverW + dx*sh->dsdx
                  + dy*sh->dsdy;
                sh->sLittle = sh->dsdy + little * sh->dsdx;
                sh->sBig = sh->sLittle - sh->dsdx;
                
                sh->frag.t = a->texture.y * oneOverW + dx*sh->dtdx
                  + dy*sh->dtdy;
                sh->tLittle = sh->dtdy + little * sh->dtdx;
                sh->tBig = sh->tLittle - sh->dtdx;
                
                sh->frag.qw = a->texture.w * oneOverW + dx*sh->dqwdx
                  + dy*sh->dqwdy;
                sh->qwLittle = sh->dqwdy + little * sh->dqwdx;
                sh->qwBig = sh->qwLittle - sh->dqwdx;
            }
        } 

        if (modeFlags & __GL_SHADE_DEPTH_ITER) 
        {
            __GLfloat zLittle, zOffset;

            zOffset = bPolygonOffset ? __glPolygonOffsetZ(gc) : 0.0f;
            if(( gc->modes.depthBits == 16 ) &&
               ( gc->depthBuffer.scale <= (GLuint)0xffff )) 
            {
                sh->frag.z = (__GLzValue)
                  FLT_TO_Z16_SCALE(a->window.z + dx*sh->dzdxf + dy*sh->dzdyf
                                     + zOffset );
                zLittle = sh->dzdyf + little * sh->dzdxf;
                sh->zLittle = FLT_TO_Z16_SCALE(zLittle);
                sh->zBig = FLT_TO_Z16_SCALE(zLittle - sh->dzdxf);
            }
            else 
            {
                sh->frag.z = (__GLzValue)
                  FTOL( a->window.z + dx*sh->dzdxf + dy*sh->dzdyf+ zOffset );
                zLittle = sh->dzdyf + little * sh->dzdxf;
                sh->zLittle = FTOL(zLittle);
                sh->zBig = FTOL(zLittle - sh->dzdxf);
            }
        }
        if (modeFlags & (__GL_SHADE_COMPUTE_FOG | __GL_SHADE_INTERP_FOG))
        {
            sh->frag.f = aFog + dx*sh->dfdx + dy*sh->dfdy;
            sh->fLittle = sh->dfdy + little * sh->dfdx;
            sh->fBig = sh->fLittle - sh->dfdx;
        }
    }
}


/* This routine sets gc->polygon.shader.cfb to gc->drawBuffer */

static void FASTCALL FillPhongSubTriangle(__GLcontext *gc, GLint iyBottom, GLint iyTop)
{
    GLint ixLeft, ixRight;
    GLint ixLeftFrac, ixRightFrac;
    GLint dxLeftFrac, dxRightFrac;
    GLint dxLeftLittle, dxRightLittle;
    GLint dxLeftBig, dxRightBig;
    GLint spanWidth, clipY0, clipY1;
    GLuint modeFlags;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLboolean needColor = (phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE);
    __GLstippleWord stackWords[__GL_MAX_STACK_STIPPLE_WORDS];
    __GLstippleWord *words;
    __GLcolor colors[__GL_MAX_STACKED_COLORS>>1];
    __GLcolor fbcolors[__GL_MAX_STACKED_COLORS>>1];
    __GLcolor *vColors, *vFbcolors;
    int iMaxWidth, iDy, dxLeft, dxRight;

    ixLeft = gc->polygon.shader.ixLeft;
    dxLeft = (gc->polygon.shader.dxLeftBig < gc->polygon.shader.dxLeftLittle) ?
             gc->polygon.shader.dxLeftBig : gc->polygon.shader.dxLeftLittle;
    ixRight = gc->polygon.shader.ixRight;
    dxRight = (gc->polygon.shader.dxRightBig > gc->polygon.shader.dxRightLittle) ?
              gc->polygon.shader.dxRightBig : gc->polygon.shader.dxRightLittle;
    iMaxWidth = ixRight - ixLeft;
    iDy = iyTop - iyBottom - 1;
    ixRight += dxRight * iDy;
    ixLeft += dxLeft * iDy;
    iMaxWidth = (iMaxWidth < (ixRight - ixLeft)) ? ixRight - ixLeft :
        iMaxWidth;
    
    if (iMaxWidth > __GL_MAX_STACK_STIPPLE_BITS)
    {
        words = gcTempAlloc(gc, (iMaxWidth+__GL_STIPPLE_BITS-1)/8);
        if (words == NULL)
        {
            return;
        }
    }
    else
    {
        words = stackWords;
    }
    
    if (iMaxWidth > (__GL_MAX_STACKED_COLORS>>1))
    {
        vColors = (__GLcolor *) gcTempAlloc(gc, 
                                               iMaxWidth * sizeof(__GLcolor));
        if (NULL == vColors)
        {
            if (iMaxWidth > __GL_MAX_STACK_STIPPLE_BITS)
            {
                gcTempFree(gc, words);
            }
            return;
        }

        vFbcolors = (__GLcolor *) gcTempAlloc(gc, 
                                                 iMaxWidth * sizeof(__GLcolor));
        if (NULL == vFbcolors) {
            if (iMaxWidth > __GL_MAX_STACK_STIPPLE_BITS)
            {
                gcTempFree(gc, words);
            }
            gcTempFree(gc, vColors);
            return;
        }
    }
    else
    {
        vColors = colors;
        vFbcolors = fbcolors;
    }

    ixLeft = gc->polygon.shader.ixLeft;
    ixLeftFrac = gc->polygon.shader.ixLeftFrac;
    ixRight = gc->polygon.shader.ixRight;
    ixRightFrac = gc->polygon.shader.ixRightFrac;
    clipY0 = gc->transform.clipY0;
    clipY1 = gc->transform.clipY1;
    dxLeftFrac = gc->polygon.shader.dxLeftFrac;
    dxLeftBig = gc->polygon.shader.dxLeftBig;
    dxLeftLittle = gc->polygon.shader.dxLeftLittle;
    dxRightFrac = gc->polygon.shader.dxRightFrac;
    dxRightBig = gc->polygon.shader.dxRightBig;
    dxRightLittle = gc->polygon.shader.dxRightLittle;
    modeFlags = gc->polygon.shader.modeFlags;

    gc->polygon.shader.colors = vColors;
    gc->polygon.shader.fbcolors = vFbcolors;
    gc->polygon.shader.stipplePat = words;
    if (modeFlags & __GL_SHADE_STENCIL_TEST) {
        gc->polygon.shader.sbuf =
          __GL_STENCIL_ADDR(&gc->stencilBuffer, (__GLstencilCell*),
                            ixLeft, iyBottom);
    }
    if (modeFlags & __GL_SHADE_DEPTH_TEST) {
    if( gc->modes.depthBits == 32 )
        gc->polygon.shader.zbuf = (__GLzValue *)
             __GL_DEPTH_ADDR(&gc->depthBuffer, (__GLzValue*),
                ixLeft, iyBottom);
    else
        gc->polygon.shader.zbuf = (__GLzValue *)
            __GL_DEPTH_ADDR(&gc->depthBuffer, (__GLz16Value*),
                ixLeft, iyBottom);
    }
    gc->polygon.shader.cfb = gc->drawBuffer;
    while (iyBottom < iyTop) 
    {
        spanWidth = ixRight - ixLeft;
        /*
        ** Only render spans that have non-zero width and which are
        ** not scissored out vertically.
        */
        if ((spanWidth > 0) && (iyBottom >= clipY0) && (iyBottom < clipY1)) 
        {
            gc->polygon.shader.frag.x = ixLeft;
            gc->polygon.shader.frag.y = iyBottom;
            gc->polygon.shader.length = spanWidth;
            /* Initialize Parameters to interpolate */
            (*gc->procs.phong.InitSpanInterpolation) (gc);
            (*gc->procs.span.processSpan)(gc);
        }

        /* Advance right edge fixed point, adjusting for carry */
        ixRightFrac += dxRightFrac;
        if (ixRightFrac < 0) 
        {
            /* Carry/Borrow'd. Use large step */
            ixRight += dxRightBig;
            ixRightFrac &= ~0x80000000;
        } 
        else 
        {
            ixRight += dxRightLittle;
        }

        iyBottom++;
        ixLeftFrac += dxLeftFrac;

        if (ixLeftFrac < 0) 
        {
            /* Carry/Borrow'd.  Use large step */
            ixLeft += dxLeftBig;
            ixLeftFrac &= ~0x80000000;
            
            phong->nCur.x += phong->nBig.x;
            phong->nCur.y += phong->nBig.y;
            phong->nCur.z += phong->nBig.z;
            
            if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
            {
                phong->eCur.x += phong->eBig.x;
                phong->eCur.y += phong->eBig.y;
                phong->eCur.z += phong->eBig.z;
                phong->eCur.w += phong->eBig.w;
            }

            if (modeFlags & __GL_SHADE_RGB) 
            {
                if (needColor) 
                {
                    gc->polygon.shader.frag.color.r +=gc->polygon.shader.rBig;
                    gc->polygon.shader.frag.color.g +=gc->polygon.shader.gBig;
                    gc->polygon.shader.frag.color.b +=gc->polygon.shader.bBig;
                    gc->polygon.shader.frag.color.a +=gc->polygon.shader.aBig;
                }
                if (modeFlags & __GL_SHADE_TEXTURE) 
                {
                    gc->polygon.shader.frag.s += gc->polygon.shader.sBig;
                    gc->polygon.shader.frag.t += gc->polygon.shader.tBig;
                    gc->polygon.shader.frag.qw += gc->polygon.shader.qwBig;
                }
            } 

            if (modeFlags & __GL_SHADE_STENCIL_TEST) {
                /* The implicit multiply is taken out of the loop */
                gc->polygon.shader.sbuf = (__GLstencilCell*)
                  ((GLubyte*) gc->polygon.shader.sbuf
                   + gc->polygon.shader.sbufBig);
            }
            if (modeFlags & __GL_SHADE_DEPTH_ITER) {
                gc->polygon.shader.frag.z += gc->polygon.shader.zBig;
            }

            if (modeFlags & __GL_SHADE_DEPTH_TEST) {
                /* The implicit multiply is taken out of the loop */
                gc->polygon.shader.zbuf = (__GLzValue*)
                  ((GLubyte*) gc->polygon.shader.zbuf
                   + gc->polygon.shader.zbufBig);
            }

            if (modeFlags & (__GL_SHADE_COMPUTE_FOG | __GL_SHADE_INTERP_FOG))
            {
                gc->polygon.shader.frag.f += gc->polygon.shader.fBig;
            }
        } 
        else 
        {
            /* Use small step */
            ixLeft += dxLeftLittle;

            phong->nCur.x += phong->nLittle.x;
            phong->nCur.y += phong->nLittle.y;
            phong->nCur.z += phong->nLittle.z;
            
            if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
            {
                phong->eCur.x += phong->eLittle.x;
                phong->eCur.y += phong->eLittle.y;
                phong->eCur.z += phong->eLittle.z;
                phong->eCur.w += phong->eLittle.w;
            }

            if (modeFlags & __GL_SHADE_RGB) 
            {
                if (needColor) 
                {
                    gc->polygon.shader.frag.color.r += 
                                               gc->polygon.shader.rLittle;
                    gc->polygon.shader.frag.color.g += 
                                               gc->polygon.shader.gLittle;
                    gc->polygon.shader.frag.color.b += 
                                               gc->polygon.shader.bLittle;
                    gc->polygon.shader.frag.color.a += 
                                               gc->polygon.shader.aLittle;
                }
                
                if (modeFlags & __GL_SHADE_TEXTURE) {
                    gc->polygon.shader.frag.s += gc->polygon.shader.sLittle;
                    gc->polygon.shader.frag.t += gc->polygon.shader.tLittle;
                    gc->polygon.shader.frag.qw += gc->polygon.shader.qwLittle;
                }
            } 

            if (modeFlags & __GL_SHADE_STENCIL_TEST) {
                /* The implicit multiply is taken out of the loop */
                gc->polygon.shader.sbuf = (__GLstencilCell*)
                  ((GLubyte*) gc->polygon.shader.sbuf
                   + gc->polygon.shader.sbufLittle);
            }
            if (modeFlags & __GL_SHADE_DEPTH_ITER) {
                gc->polygon.shader.frag.z += gc->polygon.shader.zLittle;
            }
            if (modeFlags & __GL_SHADE_DEPTH_TEST) {
                /* The implicit multiply is taken out of the loop */
                gc->polygon.shader.zbuf = (__GLzValue*)
                  ((GLubyte*) gc->polygon.shader.zbuf
                   + gc->polygon.shader.zbufLittle);
            }
            if (modeFlags & (__GL_SHADE_COMPUTE_FOG | __GL_SHADE_INTERP_FOG))
            {
                gc->polygon.shader.frag.f += gc->polygon.shader.fLittle;
            }
        }
    }
    gc->polygon.shader.ixLeft = ixLeft;
    gc->polygon.shader.ixLeftFrac = ixLeftFrac;
    gc->polygon.shader.ixRight = ixRight;
    gc->polygon.shader.ixRightFrac = ixRightFrac;
#ifdef NT
    if (iMaxWidth > __GL_MAX_STACK_STIPPLE_BITS)
    {
        gcTempFree(gc, words);
    }
    if (iMaxWidth > (__GL_MAX_STACKED_COLORS>>1))
    {
        gcTempFree(gc, vColors);
        gcTempFree(gc, vFbcolors);
    }
#endif
}

static void SnapXLeft(__GLcontext *gc, __GLfloat xLeft, __GLfloat dxdyLeft)
{
    GLint ixLeft, ixLeftFrac, lineBytes, elementSize, iLittle, iBig;

    ASSERT_CHOP_ROUND();
    
    ixLeft = __GL_VERTEX_FLOAT_TO_INT(xLeft);
    /* Pre-add .5 to allow truncation in spanWidth calculation */
    ixLeftFrac = __GL_VERTEX_PROMOTED_FRACTION(xLeft) + 0x40000000;

#ifdef __DBG_PRINT
    DbgPrint ("dxdyLeft = %f\n", dxdyLeft);
#endif
    
    gc->polygon.shader.ixLeft = ixLeft + (((GLuint) ixLeftFrac) >> 31);
    gc->polygon.shader.ixLeftFrac = ixLeftFrac & ~0x80000000;

    /* Compute big and little steps */
    iLittle = FTOL(dxdyLeft);
    gc->polygon.shader.dxLeftFrac = FLT_FRACTION(dxdyLeft - iLittle);
    if (dxdyLeft < 0) {
        iBig = iLittle - 1;
    } else {
        iBig = iLittle + 1;
    }
    if (gc->polygon.shader.modeFlags & __GL_SHADE_STENCIL_TEST) {
        /*
        ** Compute the big and little stencil buffer steps.  We walk the
        ** memory pointers for the stencil buffer along the edge of the
        ** triangle as we walk the edge.  This way we don't have to
        ** recompute the buffer address as we go.
        */
        elementSize = gc->stencilBuffer.buf.elementSize;
        lineBytes = elementSize * gc->stencilBuffer.buf.outerWidth;
        gc->polygon.shader.sbufLittle = lineBytes + iLittle * elementSize;
        gc->polygon.shader.sbufBig = lineBytes + iBig * elementSize;
    }
    if (gc->polygon.shader.modeFlags & __GL_SHADE_DEPTH_TEST) {
        /*
        ** Compute the big and little depth buffer steps.  We walk the
        ** memory pointers for the depth buffer along the edge of the
        ** triangle as we walk the edge.  This way we don't have to
        ** recompute the buffer address as we go.
        */
        elementSize = gc->depthBuffer.buf.elementSize;
        lineBytes = elementSize * gc->depthBuffer.buf.outerWidth;
        gc->polygon.shader.zbufLittle = lineBytes + iLittle * elementSize;
        gc->polygon.shader.zbufBig = lineBytes + iBig * elementSize;
    }
    gc->polygon.shader.dxLeftLittle = iLittle;
    gc->polygon.shader.dxLeftBig = iBig;
}

static void SnapXRight(__GLshade *sh, __GLfloat xRight, __GLfloat dxdyRight)
{
    GLint ixRight, ixRightFrac, iLittle, iBig;

    ASSERT_CHOP_ROUND();
    
    ixRight = __GL_VERTEX_FLOAT_TO_INT(xRight);
    /* Pre-add .5 to allow truncation in spanWidth calculation */
    ixRightFrac = __GL_VERTEX_PROMOTED_FRACTION(xRight) + 0x40000000;
    
    sh->ixRight = ixRight + (((GLuint) ixRightFrac) >> 31);
    sh->ixRightFrac = ixRightFrac & ~0x80000000;
    
    /* Compute big and little steps */
    iLittle = FTOL(dxdyRight);
    sh->dxRightFrac = FLT_FRACTION(dxdyRight - iLittle);
    if (dxdyRight < 0) {
        iBig = iLittle - 1;
    } else {
        iBig = iLittle + 1;
    }
    sh->dxRightLittle = iLittle;
    sh->dxRightBig = iBig;
}


void InitLineParamsVan (__GLcontext *gc, __GLvertex *v0, __GLvertex *v1,
                        __GLfloat invDelta)
{
    __GLcoord *n0 = &(v0->normal);
    __GLcoord *n1 = &(v1->normal);
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLuint msm_colorMaterialChange, flags=0;
    GLuint modeFlags = gc->polygon.shader.modeFlags;

    msm_colorMaterialChange = gc->light.front.colorMaterialChange;
    phong->face = __GL_FRONTFACE;

    if ((gc->state.enables.general & __GL_COLOR_MATERIAL_ENABLE) &&
        msm_colorMaterialChange && (modeFlags & __GL_SHADE_RGB))
        flags |= __GL_PHONG_NEED_COLOR_XPOLATE;

    //Compute Invariant color if possible
    if (((!(flags & __GL_PHONG_NEED_COLOR_XPOLATE) || 
        !(msm_colorMaterialChange & (__GL_MATERIAL_AMBIENT | 
                                     __GL_MATERIAL_EMISSIVE))) &&
        (modeFlags & __GL_SHADE_RGB)) &&
        !(flags & __GL_PHONG_NEED_EYE_XPOLATE))
    {
        ComputePhongInvarientRGBColor (gc);
        flags |= __GL_PHONG_INV_COLOR_VALID;
    }
    
    //Store the flags
    gc->polygon.shader.phong.flags |= flags;

    phong->dndx.x = (n1->x - n0->x) * invDelta;
    phong->dndx.y = (n1->y - n0->y) * invDelta;
    phong->dndx.z = (n1->z - n0->z) * invDelta;

    phong->nTmp.x = n0->x;
    phong->nTmp.y = n0->y;
    phong->nTmp.z = n0->z;

    if (gc->polygon.shader.phong.flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        phong->dedx.x = (v1->eyeX - v0->eyeX) * invDelta;
        phong->dedx.y = (v1->eyeY - v0->eyeY) * invDelta;
        phong->dedx.z = (v1->eyeZ - v0->eyeZ) * invDelta;

        phong->eTmp.x = v0->eyeX;
        phong->eTmp.y = v0->eyeY;
        phong->eTmp.z = v0->eyeZ;
    }
}


void InitLineParamsAccel (__GLcontext *gc, __GLvertex *v0, __GLvertex *v1,
                        __GLfloat invDelta)
{
    __GLcoord normal;
    __GLcoord *n0 = &(v0->normal);
    __GLcoord *n1 = &normal;
    __GLcoord *n2 = &(v1->normal);
    __GLlightSourceMachine *lsm;
    GLuint msm_colorMaterialChange, flags = 0;
    GLuint modeFlags = gc->polygon.shader.modeFlags;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    GLint face = phong->face, curL, w;
    
    msm_colorMaterialChange = gc->light.front.colorMaterialChange;
    phong->face = __GL_FRONTFACE;
    w = gc->line.options.numPixels;
    
    if ((gc->state.enables.general & __GL_COLOR_MATERIAL_ENABLE) &&
        msm_colorMaterialChange && (modeFlags & __GL_SHADE_RGB))
        flags |= __GL_PHONG_NEED_COLOR_XPOLATE;

    //Compute Invariant color if possible
    if (((!(flags & __GL_PHONG_NEED_COLOR_XPOLATE) || 
        !(msm_colorMaterialChange & (__GL_MATERIAL_AMBIENT | 
                                     __GL_MATERIAL_EMISSIVE))) &&
        (modeFlags & __GL_SHADE_RGB)) &&
        !(flags & __GL_PHONG_NEED_EYE_XPOLATE))
    {
        ComputePhongInvarientRGBColor (gc);
        flags |= __GL_PHONG_INV_COLOR_VALID;
    }
    
    //Store the flags
    gc->polygon.shader.phong.flags |= flags;

    phong->dndx.x = (n2->x - n0->x) * invDelta;
    phong->dndx.y = (n2->y - n0->y) * invDelta;
    phong->dndx.x = (n2->z - n0->z) * invDelta;


    normal.x = (n0->x + n2->x)/2.0f;
    normal.y = (n0->y + n2->y)/2.0f;
    normal.z = (n0->z + n2->z)/2.0f;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&normal.x, &normal.x);
    
    for (lsm = gc->light.sources, curL = 0; lsm; 
         lsm = lsm->next, curL++)
    {
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        __GLcoord *L = &(lsm->unitVPpli); // L is already normalized here
        __GLcoord *H = &(lsm->hHat);      // H is already normalized here
        GLfloat d0, d1, d2;

        /***** Diffuse *****/
        DOT (d0,n0,L);
        DOT (d1,n1,L);
        DOT (d2,n2,L);
            
        __glCalcForwardDifferences(w, d0, d1, d2, &pld->Ddel, &pld->Ddel2);
        pld->Dcurr = d0;

        /***** Specular ******/
        DOT (d0,n0,H);
        DOT (d1,n1,H);
        DOT (d2,n2,H);
            
        __glCalcForwardDifferences(w, d0, d1, d2, &pld->Sdel, &pld->Sdel2);
        pld->Scurr = d0;
    }

    phong->numLights = curL;
}


void InitSpanNEInterpolationVan (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    phong->nTmp = phong->nCur;
    phong->eTmp = phong->eCur;
}


void InitSpanNInterpolationVan (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    phong->nTmp = phong->nCur;
}

void InitSpanInterpolationAccel (__GLcontext *gc)
{
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLint face = phong->face;
    __GLlightSourceMachine *lsm;
    __GLcoord n0, n1, n2, dndx;
    __GLcoord *N0 = &n0;
    __GLcoord *N1 = &n1;
    __GLcoord *N2 = &n2;
    
    GLint curL, w, w2;
    
    w = gc->polygon.shader.length;
    w2 = w / 2;
    
    if (face == __GL_FRONTFACE)
    {
        //msm = &gc->light.front;
        n0.x = phong->nCur.x;
        n0.y = phong->nCur.y;
        n0.z = phong->nCur.z;

        dndx.x = phong->dndx.x;
        dndx.y = phong->dndx.y;
        dndx.z = phong->dndx.z;
    }
    else
    {
        //msm = &gc->light.back;
        n0.x = -phong->nCur.x;
        n0.y = -phong->nCur.y;
        n0.z = -phong->nCur.z;

        dndx.x = -phong->dndx.x;
        dndx.y = -phong->dndx.y;
        dndx.z = -phong->dndx.z;
    }
    
    if (w > 2)
    {
        n2.x = n0.x + w*dndx.x;
        n2.y = n0.y + w*dndx.y;
        n2.z = n0.z + w*dndx.z;
        
        n1.x = n0.x + w2*dndx.x;
        n1.y = n0.y + w2*dndx.y;
        n1.z = n0.z + w2*dndx.z;
    }
    
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
    {
        __glNormalize(&n0.x, &n0.x);
        if (w > 2)
        {
            __glNormalize(&n1.x, &n1.x);
            __glNormalize(&n2.x, &n2.x);
        }
    }
    
    for (lsm = gc->light.sources, curL=0; lsm; lsm = lsm->next, curL++)
    {
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        __GLcoord *L = &(lsm->unitVPpli); // L is already normalized here
        __GLcoord *H = &(lsm->hHat);      // H is already normalized here
        GLfloat d0, d1, d2;
        
        if (w > 2)
        {
            /***** Diffuse *****/
            DOT (d0,N0,L);
            DOT (d1,N1,L);
            DOT (d2,N2,L);
            
            __glCalcForwardDifferences(w, d0, d1, d2, &pld->Ddel, 
                                    &pld->Ddel2);
            pld->Dcurr = d0;
            
            /***** Specular ******/
            DOT (d0, N0, H);
            DOT (d1, N1, H);
            DOT (d2, N2, H);
            
            __glCalcForwardDifferences(w, d0, d1, d2, &pld->Sdel, 
                                    &pld->Sdel2);
            pld->Scurr = d0;
        }
        else
        {
            /***** Diffuse *****/
            DOT (d0,(&n0),L);
            pld->Dcurr = d0;
            pld->Ddel = 0.0;
            pld->Ddel2 = 0.0;

            /***** Specular ******/
            DOT (d0,(&n0),H);
            pld->Scurr = d0;
            pld->Sdel = 0.0;
            pld->Sdel2 = 0.0;
        }
    }
    phong->numLights = curL;
}


void UpdateParamsAlongSpanAccel (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
  
    for (i=0; i<phong->numLights; i++)
    {
        __GLphongPerLightData *pld = &(phong->perLight[i]);
        
        /* Diffuse */
        pld->Dcurr += pld->Ddel; 
        pld->Ddel += pld->Ddel2;

        /* Specular */
        pld->Scurr += pld->Sdel; 
        pld->Sdel += pld->Sdel2;
    }
}


void UpdateNAlongSpanVan (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    phong->nTmp.x += phong->dndx.x;
    phong->nTmp.y += phong->dndx.y;
    phong->nTmp.z += phong->dndx.z;
}

void UpdateNEAlongSpanVan (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    phong->nTmp.x += phong->dndx.x;
    phong->nTmp.y += phong->dndx.y;
    phong->nTmp.z += phong->dndx.z;

    phong->eTmp.x += phong->dedx.x;
    phong->eTmp.y += phong->dedx.y;
    phong->eTmp.z += phong->dedx.z;
    phong->eTmp.w += phong->dedx.w;
}


GLboolean FASTCALL __glPhongCISpan(__GLcontext *gc)
{
    __GLcolor *cp, outColor;
    __GLfloat r, drdx;
    __GLcoord dndx;
    GLint w;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLboolean needColor = (gc->polygon.shader.phong.flags &
                           __GL_PHONG_NEED_COLOR_XPOLATE);

    w = gc->polygon.shader.length;
    cp = gc->polygon.shader.colors;
  
    if (needColor)
    {
        phong->tmpColor.r = gc->polygon.shader.frag.color.r;
        drdx = gc->polygon.shader.drdx;
    }
    
    while (--w >= 0) 
    {
        /* Compute color using appropriate parameters */
        (*gc->procs.phong.ComputeCIColor) (gc, &outColor);

        cp->r = outColor.r;

        /* Update parameters */
        (*gc->procs.phong.UpdateAlongSpan) (gc);
        
        if (needColor)
            phong->tmpColor.r += drdx;

        cp++;
    }

    return GL_FALSE;
}

GLboolean FASTCALL __glPhongRGBASpan (__GLcontext *gc)
{
    __GLcolor *cp, dcdx, outColor;
    __GLcoord dndx;
    GLint w;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLboolean needColor = (gc->polygon.shader.phong.flags &
                           __GL_PHONG_NEED_COLOR_XPOLATE);

    w = gc->polygon.shader.length;
    cp = gc->polygon.shader.colors;

    if (needColor)
    {
        phong->tmpColor = gc->polygon.shader.frag.color;
        dcdx.r = gc->polygon.shader.drdx;
        dcdx.g = gc->polygon.shader.dgdx;
        dcdx.b = gc->polygon.shader.dbdx;
        dcdx.a = gc->polygon.shader.dadx;
    }
    
    while (--w >= 0) 
    {
        /* Compute color using appropriate parameters */
        (*gc->procs.phong.ComputeRGBColor) (gc, &outColor);
        
        cp->r = outColor.r;
        cp->g = outColor.g;
        cp->b = outColor.b;
        cp->a = outColor.a;
        
        /* Update parameters */
        (*gc->procs.phong.UpdateAlongSpan) (gc);
        
        if (needColor)
        {
            phong->tmpColor.r += dcdx.r;
            phong->tmpColor.g += dcdx.g;
            phong->tmpColor.b += dcdx.b;
            phong->tmpColor.a += dcdx.a;
        }
        cp++;
    }
    return GL_FALSE;
}


/*******************************************************************
 * RGB, Use Normal,                   Fast-lights, no ColorMaterial*
 *******************************************************************/
void ComputeRGBColorVanZippy (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLcoord n;
    __GLfloat nxi, nyi, nzi;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLfloat msm_alpha, msm_threshold, msm_scale, *msm_specTable;
    GLuint numLights;
    __GLfloat rsi=0.0, gsi=0.0, bsi=0.0;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    ASSERTOPENGL (phong->flags & __GL_PHONG_INV_COLOR_VALID, 
                  "Zippy, invarient color should have been computed\n");
    ASSERTOPENGL (!(phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE), 
                  "Zippy, no need for color interpolation\n");

    n = phong->nTmp;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    if (face == __GL_FRONTFACE)
    {
        msm = &gc->light.front;
        nxi = n.x;
        nyi = n.y;
        nzi = n.z;
    }
    else
    {
        msm = &gc->light.back;
        nxi = -n.x;
        nyi = -n.y;
        nzi = -n.z;
    }

    rsi = phong->invColor.r;
    gsi = phong->invColor.g;
    bsi = phong->invColor.b;

    msm_alpha = msm->alpha;
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    
    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        __GLfloat n1, n2;
        
        lspmm = &lsm->front + face;
        
        /* Add in specular and diffuse effect of light, if any */
        n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
          nzi * lsm->unitVPpli.z;

        if (__GL_FLOAT_GTZ(n1))
        {
            n2 = (nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * 
                  lsm->hHat.z) - msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                rsi += n2 * lspmm->specular.r;
                gsi += n2 * lspmm->specular.g;
                bsi += n2 * lspmm->specular.b;
            }
            rsi += n1 * lspmm->diffuse.r;
            gsi += n1 * lspmm->diffuse.g;
            bsi += n1 * lspmm->diffuse.b;
        }
    }
    __GL_CLAMP_R(outColor->r, gc, rsi);
    __GL_CLAMP_G(outColor->g, gc, gsi);
    __GL_CLAMP_B(outColor->b, gc, bsi);
    outColor->a = msm_alpha;
}


/*******************************************************************
 * RGB, Use Normal,                   Fast-lights, ColorMaterial   *
 *******************************************************************/
void ComputeRGBColorVanFast  (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLfloat nxi, nyi, nzi;
    __GLfloat zero;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLfloat ri, gi, bi;
    __GLfloat alpha;
    __GLcolor emissiveAmbientI;
    __GLcolor inColor;
    __GLcolor diffuseSpecularI;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLcolor lm_ambient;
    __GLfloat msm_alpha, msm_threshold, msm_scale, *msm_specTable;
    GLuint    msm_colorMaterialChange;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    __GLcoord n;
    
    zero = __glZero;


    // Optimization: If no colors have been interpolated
    // Use the Zippy function
    if (!(phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE))
        ComputeRGBColorVanZippy  (gc, outColor);
    
    inColor = phong->tmpColor;

    n = phong->nTmp;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    if (face == __GL_FRONTFACE)
    {
        msm = &gc->light.front;
        nxi = n.x;
        nyi = n.y;
        nzi = n.z;
    }
    else
    {
        msm = &gc->light.back;
        nxi = -n.x;
        nyi = -n.y;
        nzi = -n.z;
    }

    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    msm_alpha     = msm->alpha;
    msm_colorMaterialChange = msm->colorMaterialChange;

    // Save latest colors normalized to 0..1
    ri = inColor.r * gc->oneOverRedVertexScale;
    gi = inColor.g * gc->oneOverGreenVertexScale;
    bi = inColor.b * gc->oneOverBlueVertexScale;
    alpha = inColor.a;

    // Compute invarient emissive and ambient components for this vertex.
    if (phong->flags & __GL_PHONG_INV_COLOR_VALID)
    {
        emissiveAmbientI.r = phong->invColor.r;
        emissiveAmbientI.g = phong->invColor.g;
        emissiveAmbientI.b = phong->invColor.b;
    }
    else
    {
        lm_ambient.r = gc->state.light.model.ambient.r;
        lm_ambient.g = gc->state.light.model.ambient.g;
        lm_ambient.b = gc->state.light.model.ambient.b;

        baseEmissiveAmbient.r = msm->paSceneColor.r;
        baseEmissiveAmbient.g = msm->paSceneColor.g;
        baseEmissiveAmbient.b = msm->paSceneColor.b;
        
        if (msm_colorMaterialChange & __GL_MATERIAL_AMBIENT)
        {
            emissiveAmbientI.r = baseEmissiveAmbient.r
              + ri * lm_ambient.r;
            emissiveAmbientI.g = baseEmissiveAmbient.g
              + gi * lm_ambient.g;
            emissiveAmbientI.b = baseEmissiveAmbient.b
              + bi * lm_ambient.b;

            // Add per-light per-material ambient
            for (lsm = gc->light.sources; lsm; lsm = lsm->next)
            {
                lss = lsm->state;
                emissiveAmbientI.r += ri * lss->ambient.r;
                emissiveAmbientI.g += gi * lss->ambient.g;
                emissiveAmbientI.b += bi * lss->ambient.b;
            }
        }
        else
        {
            for (lsm = gc->light.sources; lsm; lsm = lsm->next)
            {
                lspmm = &lsm->front + face;
                baseEmissiveAmbient.r += lspmm->ambient.r;
                baseEmissiveAmbient.g += lspmm->ambient.g;
                baseEmissiveAmbient.b += lspmm->ambient.b;
            }
            emissiveAmbientI.r = baseEmissiveAmbient.r + inColor.r;
            emissiveAmbientI.g = baseEmissiveAmbient.g + inColor.g;
            emissiveAmbientI.b = baseEmissiveAmbient.b + inColor.b;
        }
    }

    // Compute the diffuse and specular components for this vertex.

    diffuseSpecularI.r = zero;
    diffuseSpecularI.g = zero;
    diffuseSpecularI.b = zero;

    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        __GLfloat n1, n2;

        lss = lsm->state;
        lspmm = &lsm->front + face;

        /* Add in specular and diffuse effect of light, if any */
        n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
          nzi * lsm->unitVPpli.z;

        if (__GL_FLOAT_GTZ(n1))
        {
            n2 = nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * lsm->hHat.z;
            n2 -= msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                if (msm_colorMaterialChange & __GL_MATERIAL_SPECULAR)
                {
                    /* Recompute per-light per-material cached specular */
                    diffuseSpecularI.r += n2 * ri * lss->specular.r;
                    diffuseSpecularI.g += n2 * gi * lss->specular.g;
                    diffuseSpecularI.b += n2 * bi * lss->specular.b;
                }
                else
                {
                    diffuseSpecularI.r += n2 * lspmm->specular.r;
                    diffuseSpecularI.g += n2 * lspmm->specular.g;
                    diffuseSpecularI.b += n2 * lspmm->specular.b;
                }
            }

            if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
            {
                /* Recompute per-light per-material cached diffuse */
                diffuseSpecularI.r += n1 * ri * lss->diffuse.r;
                diffuseSpecularI.g += n1 * gi * lss->diffuse.g;
                diffuseSpecularI.b += n1 * bi * lss->diffuse.b;
            }
            else
            {
                diffuseSpecularI.r += n1 * lspmm->diffuse.r;
                diffuseSpecularI.g += n1 * lspmm->diffuse.g;
                diffuseSpecularI.b += n1 * lspmm->diffuse.b;
            }
        }
    }

    __GL_CLAMP_R(outColor->r, gc, emissiveAmbientI.r + diffuseSpecularI.r);
    __GL_CLAMP_G(outColor->g, gc, emissiveAmbientI.g + diffuseSpecularI.g);
    __GL_CLAMP_B(outColor->b, gc, emissiveAmbientI.b + diffuseSpecularI.b);

    if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
    {
        __GL_CLAMP_A(outColor->a, gc, alpha);
    }
    else
        outColor->a = msm_alpha;
}


/*******************************************************************
 * RGB, Use Normal,                   Slow-lights, ColorMaterial   *
 *******************************************************************/
void ComputeRGBColorVanSlow  (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLfloat nxi, nyi, nzi;
    __GLfloat zero;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLfloat ri, gi, bi;
    __GLfloat alpha;
    __GLfloat rsi, gsi, bsi;
    __GLcolor sceneColorI;
    __GLmaterialMachine *msm;
    __GLcolor inColor;
     __GLcolor lm_ambient;
    __GLfloat msm_alpha, msm_threshold, msm_scale, *msm_specTable;
    __GLcolor msm_paSceneColor;
    GLuint    msm_colorMaterialChange;
    GLboolean eyeWIsZero, localViewer;
    static __GLcoord Pe = { 0, 0, 0, 1 };
    __GLcoord n;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
 
    zero = __glZero;

    inColor = phong->tmpColor;

    n = phong->nTmp;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    if (face == __GL_FRONTFACE)
    {
        msm = &gc->light.front;
        nxi = n.x;
        nyi = n.y;
        nzi = n.z;
    }
    else
    {
        msm = &gc->light.back;
        nxi = -n.x;
        nyi = -n.y;
        nzi = -n.z;
    }
 
    lm_ambient.r = gc->state.light.model.ambient.r;
    lm_ambient.g = gc->state.light.model.ambient.g;
    lm_ambient.b = gc->state.light.model.ambient.b;

    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    msm_alpha     = msm->alpha;
    msm_colorMaterialChange = msm->colorMaterialChange;
    msm_paSceneColor = msm->paSceneColor;

    localViewer = gc->state.light.model.localViewer;

    // Get invarient scene color if there is no ambient or emissive color 
    // material.

    sceneColorI.r = msm_paSceneColor.r;
    sceneColorI.g = msm_paSceneColor.g;
    sceneColorI.b = msm_paSceneColor.b;

    if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        // Save latest colors normalized to 0..1
            
        ri = inColor.r * gc->oneOverRedVertexScale;
        gi = inColor.g * gc->oneOverGreenVertexScale;
        bi = inColor.b * gc->oneOverBlueVertexScale;
        alpha = inColor.a;

        // Compute scene color.
        // If color has not changed, the previous sceneColorI values are 
        // used!

        if (msm_colorMaterialChange & (__GL_MATERIAL_AMBIENT | 
                                       __GL_MATERIAL_EMISSIVE))
        {
            if (msm_colorMaterialChange & __GL_MATERIAL_AMBIENT)
            {
                sceneColorI.r = msm_paSceneColor.r + ri * lm_ambient.r;
                sceneColorI.g = msm_paSceneColor.g + gi * lm_ambient.g;
                sceneColorI.b = msm_paSceneColor.b + bi * lm_ambient.b;
            }
            else
            {
                sceneColorI.r = msm_paSceneColor.r + inColor.r;
                sceneColorI.g = msm_paSceneColor.g + inColor.g;
                sceneColorI.b = msm_paSceneColor.b + inColor.b;
            }
        }
    }
        
    // Compute the diffuse and specular components for this vertex.
    rsi = sceneColorI.r;
    gsi = sceneColorI.g;
    bsi = sceneColorI.b;

    eyeWIsZero = __GL_FLOAT_EQZ(phong->eTmp.w);
    
    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        __GLfloat n1, n2;
            
        lss = lsm->state;
        lspmm = &lsm->front + face;
            
        if (lsm->slowPath || eyeWIsZero)
        {
            __GLcoord hHat, vPli, vPliHat, vPeHat;
            __GLfloat att, attSpot;
            __GLfloat hv[3];
                
            /* Compute unit h[i] */
            __glVecSub4(&vPli, &phong->eTmp, &lsm->position);
            __glNormalize(&vPliHat.x, &vPli.x);
            if (localViewer)
            {
                __glVecSub4(&vPeHat, &phong->eTmp, &Pe);
                __glNormalize(&vPeHat.x, &vPeHat.x);
                hv[0] = vPliHat.x + vPeHat.x;
                hv[1] = vPliHat.y + vPeHat.y;
                hv[2] = vPliHat.z + vPeHat.z;
            }
            else
            {
                hv[0] = vPliHat.x;
                hv[1] = vPliHat.y;
                hv[2] = vPliHat.z + __glOne;
            }
            __glNormalize(&hHat.x, hv);
                
            /* Compute attenuation */
            if (__GL_FLOAT_NEZ(lsm->position.w))
            {
                __GLfloat k0, k1, k2, dist;
                    
                k0 = lsm->constantAttenuation;
                k1 = lsm->linearAttenuation;
                k2 = lsm->quadraticAttenuation;
                if (__GL_FLOAT_EQZ(k1) && __GL_FLOAT_EQZ(k2))
                {
                    /* Use pre-computed 1/k0 */
                    att = lsm->attenuation;
                }
                else
                {
                    __GLfloat den;

                    dist = __GL_SQRTF(vPli.x*vPli.x + vPli.y*vPli.y
                                      + vPli.z*vPli.z);
                    den = k0 + k1 * dist + k2 * dist * dist;
                    att = __GL_FLOAT_EQZ(den) ? __glOne : __glOne / den;
                }
            }
            else
            {
                att = __glOne;
            }
                
            /* Compute spot effect if light is a spot light */
            attSpot = att;
            if (lsm->isSpot)
            {
                __GLfloat dot, px, py, pz;
                    
                px = -vPliHat.x;
                py = -vPliHat.y;
                pz = -vPliHat.z;
                dot = px * lsm->direction.x + py * lsm->direction.y
                      + pz * lsm->direction.z;
                if ((dot >= lsm->threshold) && (dot >= lsm->cosCutOffAngle))
                {
                    GLint ix = (GLint)((dot - lsm->threshold) * lsm->scale 
                                       + __glHalf);
                    if (ix < __GL_SPOT_LOOKUP_TABLE_SIZE)
                        attSpot = att * lsm->spotTable[ix];
                }
                else
                {
                    attSpot = zero;
                }
            }
                
            /* Add in remaining effect of light, if any */
            if (attSpot)
            {
                __GLfloat n1, n2;
                __GLcolor sum;
                    
                if (msm_colorMaterialChange & __GL_MATERIAL_AMBIENT)
                {
                    sum.r = ri * lss->ambient.r;
                    sum.g = gi * lss->ambient.g;
                    sum.b = bi * lss->ambient.b;
                }
                else
                {
                    sum.r = lspmm->ambient.r;
                    sum.g = lspmm->ambient.g;
                    sum.b = lspmm->ambient.b;
                }
                    
                n1 = nxi * vPliHat.x + nyi * vPliHat.y + nzi * vPliHat.z;
                if (__GL_FLOAT_GTZ(n1))
                {
                    n2 = nxi * hHat.x + nyi * hHat.y + nzi * hHat.z;
                    n2 -= msm_threshold;
                    if (__GL_FLOAT_GEZ(n2))
                    {
                        __GLfloat fx = n2 * msm_scale + __glHalf;
                        if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                            n2 = msm_specTable[(GLint)fx];
                        else
                            n2 = __glOne;
                        if (msm_colorMaterialChange & __GL_MATERIAL_SPECULAR)
                        {
                            /* Recompute per-light per-material cached specular */
                            sum.r += n2 * ri * lss->specular.r;
                            sum.g += n2 * gi * lss->specular.g;
                            sum.b += n2 * bi * lss->specular.b;
                        }
                        else
                        {
                            sum.r += n2 * lspmm->specular.r;
                            sum.g += n2 * lspmm->specular.g;
                            sum.b += n2 * lspmm->specular.b;
                        }
                    }
                    if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
                    {
                        /* Recompute per-light per-material cached diffuse */
                        sum.r += n1 * ri * lss->diffuse.r;
                        sum.g += n1 * gi * lss->diffuse.g;
                        sum.b += n1 * bi * lss->diffuse.b;
                    }
                    else
                    {
                        sum.r += n1 * lspmm->diffuse.r;
                        sum.g += n1 * lspmm->diffuse.g;
                        sum.b += n1 * lspmm->diffuse.b;
                    }
                }
                    
                rsi += attSpot * sum.r;
                gsi += attSpot * sum.g;
                bsi += attSpot * sum.b;
            }
        }
        else
        {
            __GLfloat n1, n2;
                
            if (msm_colorMaterialChange & __GL_MATERIAL_AMBIENT)
            {
                rsi += ri * lss->ambient.r;
                gsi += gi * lss->ambient.g;
                bsi += bi * lss->ambient.b;
            }
            else
            {
                rsi += lspmm->ambient.r;
                gsi += lspmm->ambient.g;
                bsi += lspmm->ambient.b;
            }
                
            /* Add in specular and diffuse effect of light, if any */
            n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
                 nzi * lsm->unitVPpli.z;
            if (__GL_FLOAT_GTZ(n1))
            {
                n2= nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * lsm->hHat.z;
                n2 -= msm_threshold;
                if (__GL_FLOAT_GEZ(n2)) 
                {
                    __GLfloat fx = n2 * msm_scale + __glHalf;
                    if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                        n2 = msm_specTable[(GLint)fx];
                    else
                        n2 = __glOne;
                    if (msm_colorMaterialChange & __GL_MATERIAL_SPECULAR)
                    {
                        /* Recompute per-light per-material cached specular */
                        rsi += n2 * ri * lss->specular.r;
                        gsi += n2 * gi * lss->specular.g;
                        bsi += n2 * bi * lss->specular.b;
                    }
                    else
                    {
                        rsi += n2 * lspmm->specular.r;
                        gsi += n2 * lspmm->specular.g;
                        bsi += n2 * lspmm->specular.b;
                    }
                }
                if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
                {
                    /* Recompute per-light per-material cached diffuse */
                    rsi += n1 * ri * lss->diffuse.r;
                    gsi += n1 * gi * lss->diffuse.g;
                    bsi += n1 * bi * lss->diffuse.b;
                }
                else
                {
                    rsi += n1 * lspmm->diffuse.r;
                    gsi += n1 * lspmm->diffuse.g;
                    bsi += n1 * lspmm->diffuse.b;
                }
            }
        }
    }
        
    __GL_CLAMP_R(outColor->r, gc, rsi);
    __GL_CLAMP_G(outColor->g, gc, gsi);
    __GL_CLAMP_B(outColor->b, gc, bsi);
          
    if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
    {
        __GL_CLAMP_A(outColor->a, gc, alpha);
    }
    else
        outColor->a = msm_alpha;
}

/*******************************************************************
 * RGB, Use Dot,                Fast-lights, no ColorMaterial      *
 *******************************************************************/
void ComputeRGBColorAccelZippy (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLfloat msm_alpha, msm_threshold, msm_scale, *msm_specTable;
    GLuint numLights;
    __GLfloat rsi=0.0, gsi=0.0, bsi=0.0;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLint curL;

    if (face == __GL_FRONTFACE)
        msm = &gc->light.front;
    else
        msm = &gc->light.back;

    ASSERTOPENGL (phong->flags & __GL_PHONG_INV_COLOR_VALID, 
                  "Zippy, invarient color should have been computed\n");
    ASSERTOPENGL (!(phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE), 
                  "Zippy, no need for color interpolation\n");

    rsi = phong->invColor.r;
    gsi = phong->invColor.g;
    bsi = phong->invColor.b;
    msm_alpha = msm->alpha;
   
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    
    for (lsm = gc->light.sources, curL = 0; lsm; lsm = lsm->next, curL++)
    {
        __GLfloat n1, n2, x, y, x2, y2;
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        __GLfloat a, b, c, d, e, f, g, h, i;   
        
        /* Add in specular and diffuse effect of light, if any */
        n1 = pld->Dcurr;
        lspmm = &lsm->front + face;
        if (__GL_FLOAT_GTZ(n1))
        {
#ifdef __FASTEST
            n2 = pld->Scurr - msm_threshold;
#endif //__FASTEST
#ifdef __SLOW
            x = phong->tmp_pos.x; x2 = x*x;
            y = phong->tmp_pos.y; y2 = y*y;

            a = pld->A[0]; b = pld->A[1];
            c = pld->A[2]; d = pld->A[3];
            e = pld->A[4]; f = pld->A[5];
            g = pld->A[6]; h = pld->A[7];
            i = pld->A[8];
        
            n2 = (a*x+b*y+c)/__GL_SQRTF(d*x2+e*x*y+f*y2+g*x+h*y+i);
#endif //__SLOW
#ifdef __FASTER
            x = phong->tmp_pos.x; x2 = x*x;
            y = phong->tmp_pos.y; y2 = y*y;

            n2 = pld->S[5]*x2 + pld->S[4]*x*y + pld->S[3]*y2 + pld->S[2]*x + 
              pld->S[1]*y + pld->S[0];
#endif //__FASTER
        
            //n2 -= msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                rsi += n2 * lspmm->specular.r;
                gsi += n2 * lspmm->specular.g;
                bsi += n2 * lspmm->specular.b;
                
            }
            rsi += n1 * lspmm->diffuse.r;
            gsi += n1 * lspmm->diffuse.g;
            bsi += n1 * lspmm->diffuse.b;
        }
    }
    __GL_CLAMP_R(outColor->r, gc, rsi);
    __GL_CLAMP_G(outColor->g, gc, gsi);
    __GL_CLAMP_B(outColor->b, gc, bsi);
    outColor->a = msm_alpha;
}


/*******************************************************************
 * RGB, Use Dot,                Fast-lights, ColorMaterial         *
 *******************************************************************/
void ComputeRGBColorAccelFast  (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLfloat zero;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLfloat ri, gi, bi;
    __GLfloat alpha;
    __GLcolor emissiveAmbientI;
    __GLcolor inColor;
    __GLcolor diffuseSpecularI;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLcolor lm_ambient;
    __GLfloat msm_alpha, msm_threshold, msm_scale, *msm_specTable;
    GLuint    msm_colorMaterialChange;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLint curL;
    
    zero = __glZero;

    if (face == __GL_FRONTFACE)
        msm = &gc->light.front;
    else
        msm = &gc->light.back;

    msm_colorMaterialChange = msm->colorMaterialChange;

    ASSERTOPENGL (phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE, 
                  "Fast, need  color interpolation\n");
#if 0
    ASSERTOPENGL (!(gc->state.enables.general & __GL_NORMALIZE_ENABLE), 
                  "Normalization should have been disabled\n");
#endif

    inColor = phong->tmpColor;
    
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    msm_alpha     = msm->alpha;

    // Save latest colors normalized to 0..1
    ri = inColor.r * gc->oneOverRedVertexScale;
    gi = inColor.g * gc->oneOverGreenVertexScale;
    bi = inColor.b * gc->oneOverBlueVertexScale;
    alpha = inColor.a;

    // Compute invarient emissive and ambient components for this vertex.
    if (phong->flags & __GL_PHONG_INV_COLOR_VALID)
    {
        emissiveAmbientI.r = phong->invColor.r;
        emissiveAmbientI.g = phong->invColor.g;
        emissiveAmbientI.b = phong->invColor.b;
    }
    else
    {
        lm_ambient.r = gc->state.light.model.ambient.r;
        lm_ambient.g = gc->state.light.model.ambient.g;
        lm_ambient.b = gc->state.light.model.ambient.b;

        baseEmissiveAmbient.r = msm->paSceneColor.r;
        baseEmissiveAmbient.g = msm->paSceneColor.g;
        baseEmissiveAmbient.b = msm->paSceneColor.b;
        
        if (msm_colorMaterialChange & __GL_MATERIAL_AMBIENT)
        {
            emissiveAmbientI.r = baseEmissiveAmbient.r
              + ri * lm_ambient.r;
            emissiveAmbientI.g = baseEmissiveAmbient.g
              + gi * lm_ambient.g;
            emissiveAmbientI.b = baseEmissiveAmbient.b
              + bi * lm_ambient.b;

            // Add per-light per-material ambient
            for (lsm = gc->light.sources; lsm; lsm = lsm->next)
            {
                lss = lsm->state;
                emissiveAmbientI.r += ri * lss->ambient.r;
                emissiveAmbientI.g += gi * lss->ambient.g;
                emissiveAmbientI.b += bi * lss->ambient.b;
            }
        }
        else
        {
            for (lsm = gc->light.sources; lsm; lsm = lsm->next)
            {
                lspmm = &lsm->front + face;
                baseEmissiveAmbient.r += lspmm->ambient.r;
                baseEmissiveAmbient.g += lspmm->ambient.g;
                baseEmissiveAmbient.b += lspmm->ambient.b;
            }
            emissiveAmbientI.r = baseEmissiveAmbient.r + inColor.r;
            emissiveAmbientI.g = baseEmissiveAmbient.g + inColor.g;
            emissiveAmbientI.b = baseEmissiveAmbient.b + inColor.b;
        }
    }

    // Compute the diffuse and specular components for this vertex.
    diffuseSpecularI.r = zero;
    diffuseSpecularI.g = zero;
    diffuseSpecularI.b = zero;

    for (lsm = gc->light.sources, curL=0; lsm; lsm = lsm->next, curL++)
    {
        __GLfloat n1, n2;
        __GLphongPerLightData *pld = &(phong->perLight[curL]);

        lss = lsm->state;
        lspmm = &lsm->front + face;

        /* Add in specular and diffuse effect of light, if any */
        n1 = pld->Dcurr;

        if (__GL_FLOAT_GTZ(n1))
        {
            n2 = pld->Scurr - msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                if (msm_colorMaterialChange & __GL_MATERIAL_SPECULAR)
                {
                    /* Recompute per-light per-material cached specular */
                    diffuseSpecularI.r += n2 * ri * lss->specular.r;
                    diffuseSpecularI.g += n2 * gi * lss->specular.g;
                    diffuseSpecularI.b += n2 * bi * lss->specular.b;
                }
                else
                {
                    diffuseSpecularI.r += n2 * lspmm->specular.r;
                    diffuseSpecularI.g += n2 * lspmm->specular.g;
                    diffuseSpecularI.b += n2 * lspmm->specular.b;
                }
            }

            if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
            {
                /* Recompute per-light per-material cached diffuse */
                diffuseSpecularI.r += n1 * ri * lss->diffuse.r;
                diffuseSpecularI.g += n1 * gi * lss->diffuse.g;
                diffuseSpecularI.b += n1 * bi * lss->diffuse.b;
            }
            else
            {
                diffuseSpecularI.r += n1 * lspmm->diffuse.r;
                diffuseSpecularI.g += n1 * lspmm->diffuse.g;
                diffuseSpecularI.b += n1 * lspmm->diffuse.b;
            }
        }
    }

    __GL_CLAMP_R(outColor->r, gc, emissiveAmbientI.r + diffuseSpecularI.r);
    __GL_CLAMP_G(outColor->g, gc, emissiveAmbientI.g + diffuseSpecularI.g);
    __GL_CLAMP_B(outColor->b, gc, emissiveAmbientI.b + diffuseSpecularI.b);

    if (msm_colorMaterialChange & __GL_MATERIAL_DIFFUSE)
    {
        __GL_CLAMP_A(outColor->a, gc, alpha);
    }
    else
        outColor->a = msm_alpha;
}


/*******************************************************************
 * CI, Vanilla,                      Fast-lights                   *
 *******************************************************************/
void ComputeCIColorVanFast (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLfloat zero;
    __GLcoord n;
    __GLfloat nxi, nyi, nzi;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLmaterialState *ms;
    __GLfloat msm_threshold, msm_scale, *msm_specTable;
    GLuint numLights;
    __GLfloat ms_cmapa, ms_cmapd, ms_cmaps;
    __GLfloat ci, si, di;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLfloat   redMaxF;
    GLint     redMaxI;

    zero = __glZero;

    n = phong->nTmp;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    if (face == __GL_FRONTFACE)
    {
        ms  = &gc->state.light.front;
        msm = &gc->light.front;
        nxi = n.x;
        nyi = n.y;
        nzi = n.z;
    }
    else
    {
        ms  = &gc->state.light.back;
        msm = &gc->light.back;
        nxi = -n.x;
        nyi = -n.y;
        nzi = -n.z;
    }
    
    ASSERTOPENGL (!(phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE), 
                  "Zippy, no need for color interpolation\n");
   
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    ms_cmapa = ms->cmapa;
    ms_cmapd = ms->cmapd;
    ms_cmaps = ms->cmaps;
    redMaxF = (GLfloat) gc->frontBuffer.redMax;
    redMaxI = (GLint) gc->frontBuffer.redMax;
    
    si = zero;
    di = zero;

    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        __GLfloat n1, n2;
        
        lspmm = &lsm->front + face;
        
        /* Add in specular and diffuse effect of light, if any */
        n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
          nzi * lsm->unitVPpli.z;

        if (__GL_FLOAT_GTZ(n1))
        {
            n2 = (nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * 
                  lsm->hHat.z) - msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                si += n2 * lsm->sli;
            }
            di += n1 * lsm->dli;
        }
    }

	/* Compute final color */
	if (si > __glOne)
	    si = __glOne;

	ci = ms_cmapa + (__glOne - si) * di * (ms_cmapd - ms_cmapa)
	    + si * (ms_cmaps - ms_cmapa);

    // need to mask color index before color clipping
	if (ci > redMaxF) 
    {
	    GLfloat fraction;
	    GLint integer;

	    integer = (GLint) ci;
	    fraction = ci - (GLfloat) integer;
	    integer = integer & redMaxI;
	    ci = (GLfloat) integer + fraction;
	} 
    else if (ci < 0) 
    {
	    GLfloat fraction;
	    GLint integer;

	    integer = (GLint) __GL_FLOORF(ci);
	    fraction = ci - (GLfloat) integer;
	    integer = integer & redMaxI;
	    ci = (GLfloat) integer + fraction;
	}

    outColor->r = ci;
}


/*******************************************************************
 * CI, Vanilla,                      Slow-lights                   *
 *******************************************************************/
void ComputeCIColorVanSlow  (__GLcontext *gc, __GLcolor *outColor)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLfloat nxi, nyi, nzi;
    __GLfloat zero;
    __GLlightSourceMachine *lsm;
    __GLmaterialState *ms;
    __GLmaterialMachine *msm;
    __GLfloat msm_threshold, msm_scale, *msm_specTable;
    __GLfloat ms_cmapa, ms_cmapd, ms_cmaps;
    __GLfloat ci, si, di;
    GLfloat   redMaxF;
    GLint     redMaxI;
    GLboolean eyeWIsZero, localViewer;
    static __GLcoord Pe = { 0, 0, 0, 1 };
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    __GLcoord n;


    zero = __glZero;

    n = phong->nTmp;
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);

    if (face == __GL_FRONTFACE)
    {
        ms  = &gc->state.light.front;
        msm = &gc->light.front;
        nxi = n.x;
        nyi = n.y;
        nzi = n.z;
    }
    else
    {
        ms  = &gc->state.light.back;
        msm = &gc->light.back;
        nxi = -n.x;
        nyi = -n.y;
        nzi = -n.z;
    }
    
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    ms_cmapa = ms->cmapa;
    ms_cmapd = ms->cmapd;
    ms_cmaps = ms->cmaps;
    localViewer = gc->state.light.model.localViewer;
    redMaxF = (GLfloat) gc->frontBuffer.redMax;
    redMaxI = (GLint) gc->frontBuffer.redMax;


    si = zero;
    di = zero;

    eyeWIsZero = __GL_FLOAT_EQZ(phong->eTmp.w);

    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        if (lsm->slowPath || eyeWIsZero)
        {
            __GLfloat n1, n2, att, attSpot;
            __GLcoord vPliHat, vPli, hHat, vPeHat;
            __GLfloat hv[3];

            /* Compute vPli, hi (normalized) */
            __glVecSub4(&vPli, &phong->eTmp, &lsm->position);
            __glNormalize(&vPliHat.x, &vPli.x);
            if (localViewer)
            {
                __glVecSub4(&vPeHat, &phong->eTmp, &Pe);
                __glNormalize(&vPeHat.x, &vPeHat.x);
                hv[0] = vPliHat.x + vPeHat.x;
                hv[1] = vPliHat.y + vPeHat.y;
                hv[2] = vPliHat.z + vPeHat.z;
            }
            else
            {
                hv[0] = vPliHat.x;
                hv[1] = vPliHat.y;
                hv[2] = vPliHat.z + __glOne;
            }
            __glNormalize(&hHat.x, hv);

            /* Compute attenuation */
            if (__GL_FLOAT_NEZ(lsm->position.w))
            {
                __GLfloat k0, k1, k2, dist;

                k0 = lsm->constantAttenuation;
                k1 = lsm->linearAttenuation;
                k2 = lsm->quadraticAttenuation;
                if (__GL_FLOAT_EQZ(k1) && __GL_FLOAT_EQZ(k2))
                {
                    /* Use pre-computed 1/k0 */
                    att = lsm->attenuation;
                }
                else
                {
                    __GLfloat den;

                    dist = __GL_SQRTF(vPli.x*vPli.x + vPli.y*vPli.y
                                      + vPli.z*vPli.z);
                    den = k0 + k1 * dist + k2 * dist * dist;
                    att = __GL_FLOAT_EQZ(den) ? __glOne : __glOne / den;
                }
            }
            else
            {
                att = __glOne;
            }

            /* Compute spot effect if light is a spot light */
            attSpot = att;
            if (lsm->isSpot)
            {
                __GLfloat dot, px, py, pz;

                px = -vPliHat.x;
                py = -vPliHat.y;
                pz = -vPliHat.z;
                dot = px * lsm->direction.x + py * lsm->direction.y
                      + pz * lsm->direction.z;
                if ((dot >= lsm->threshold) && (dot >= lsm->cosCutOffAngle))
                {
                    GLint ix = (GLint)((dot - lsm->threshold) * lsm->scale 
                                       + __glHalf);
                    if (ix < __GL_SPOT_LOOKUP_TABLE_SIZE)
                        attSpot = att * lsm->spotTable[ix];
                }
                else
                {
                  attSpot = zero;
                }
            }

            /* Add in remaining effect of light, if any */
            if (attSpot)
            {
                n1 = nxi * vPliHat.x + nyi * vPliHat.y + nzi * vPliHat.z;
                if (__GL_FLOAT_GTZ(n1)) 
                {
                    n2 = nxi * hHat.x + nyi * hHat.y + nzi * hHat.z;
                    n2 -= msm_threshold;
                    if (__GL_FLOAT_GEZ(n2))
                    {
                        __GLfloat fx = n2 * msm_scale + __glHalf;
                        if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                            n2 = msm_specTable[(GLint)fx];
                        else
                            n2 = __glOne;
                        si += attSpot * n2 * lsm->sli;
                    }
                    di += attSpot * n1 * lsm->dli;
                }
            }
        }
        else
        {
            __GLfloat n1, n2;

            /* Compute specular contribution */
            n1 = nxi * lsm->unitVPpli.x + nyi * lsm->unitVPpli.y +
                 nzi * lsm->unitVPpli.z;
            if (__GL_FLOAT_GTZ(n1))
            {
                n2= nxi * lsm->hHat.x + nyi * lsm->hHat.y + nzi * lsm->hHat.z;
                n2 -= msm_threshold;
                if (__GL_FLOAT_GEZ(n2))
                {
                    __GLfloat fx = n2 * msm_scale + __glHalf;
                    if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                        n2 = msm_specTable[(GLint)fx];
                    else
                        n2 = __glOne;
                    si += n2 * lsm->sli;
                }
                di += n1 * lsm->dli;
            }
        }
    }

    /* Compute final color */
    if (si > __glOne)
        si = __glOne;

    ci = ms_cmapa + (__glOne - si) * di * (ms_cmapd - ms_cmapa)
        + si * (ms_cmaps - ms_cmapa);
    if (ci > ms_cmaps)
        ci = ms_cmaps;

    // need to mask color index before color clipping

    if (ci > redMaxF) 
    {
        GLfloat fraction;
        GLint integer;

        integer = (GLint) ci;
        fraction = ci - (GLfloat) integer;
        integer = integer & redMaxI;
        ci = (GLfloat) integer + fraction;
    } 
    else if (ci < 0) 
    {
        GLfloat fraction;
        GLint integer;

        integer = (GLint) __GL_FLOORF(ci);
        fraction = ci - (GLfloat) integer;
        integer = integer & redMaxI;
        ci = (GLfloat) integer + fraction;
    }
    outColor->r = ci;
}



/*******************************************************************
 * CI, Fast-lights, Fast-path                                      *
 *******************************************************************/
void ComputeCIColorAccelFast (__GLcontext *gc, __GLcolor *outColor)
{
    __GLfloat zero;
    GLint face = gc->polygon.shader.phong.face;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLcolor baseEmissiveAmbient;
    __GLmaterialMachine *msm;
    __GLmaterialState *ms;
    __GLfloat msm_threshold, msm_scale, *msm_specTable;
    GLuint numLights;
    __GLfloat ms_cmapa, ms_cmapd, ms_cmaps;
    __GLfloat ci, si, di;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLfloat   redMaxF;
    GLint     redMaxI;
    GLint curL;

    zero = __glZero;

    if (face == __GL_FRONTFACE)
    {
        ms  = &gc->state.light.front;
        msm = &gc->light.front;
    }
    else
    {
        ms  = &gc->state.light.back;
        msm = &gc->light.back;
    }
    

    ASSERTOPENGL (!(phong->flags & __GL_PHONG_NEED_COLOR_XPOLATE), 
                  "Zippy, no need for color interpolation\n");
   
    msm_scale     = msm->scale;
    msm_threshold = msm->threshold;
    msm_specTable = msm->specTable;
    ms_cmapa = ms->cmapa;
    ms_cmapd = ms->cmapd;
    ms_cmaps = ms->cmaps;
    redMaxF = (GLfloat) gc->frontBuffer.redMax;
    redMaxI = (GLint) gc->frontBuffer.redMax;
    
    si = zero;
    di = zero;

    for (lsm = gc->light.sources, curL=0; lsm; lsm = lsm->next, curL++)
    {
        __GLfloat n1, n2;
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        
        lspmm = &lsm->front + face;
        
        /* Add in specular and diffuse effect of light, if any */
        n1 = pld->Dcurr;
        if (__GL_FLOAT_GTZ(n1))
        {
            n2 = pld->Scurr - msm_threshold;
            if (__GL_FLOAT_GEZ(n2))
            {
                __GLfloat fx = n2 * msm_scale + __glHalf;
                
                if( fx < (__GLfloat)__GL_SPEC_LOOKUP_TABLE_SIZE )
                    n2 = msm_specTable[(GLint)fx];
                else
                    n2 = __glOne;
                si += n2 * lsm->sli;
            }
            di += n1 * lsm->dli;
        }
    }

	/* Compute final color */
	if (si > __glOne)
	    si = __glOne;

	ci = ms_cmapa + (__glOne - si) * di * (ms_cmapd - ms_cmapa)
	    + si * (ms_cmaps - ms_cmapa);

    // need to mask color index before color clipping
	if (ci > redMaxF) 
    {
	    GLfloat fraction;
	    GLint integer;

	    integer = (GLint) ci;
	    fraction = ci - (GLfloat) integer;
	    integer = integer & redMaxI;
	    ci = (GLfloat) integer + fraction;
	} 
    else if (ci < 0) 
    {
	    GLfloat fraction;
	    GLint integer;

	    integer = (GLint) __GL_FLOORF(ci);
	    fraction = ci - (GLfloat) integer;
	    integer = integer & redMaxI;
	    ci = (GLfloat) integer + fraction;
	}

    outColor->r = ci;
}


void ComputePhongInvarientRGBColor (__GLcontext *gc)
{
    GLint face = gc->polygon.shader.phong.face;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLlightSourceState *lss;
    __GLmaterialMachine *msm;
    __GLfloat msm_alpha;
    __GLfloat rsi, gsi, bsi;
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    if (face == __GL_FRONTFACE)
        msm = &gc->light.front;
    else
        msm = &gc->light.back;

    // Compute invarient emissive and ambient components for this vertex.

    rsi = msm->paSceneColor.r;
    gsi = msm->paSceneColor.g;
    bsi = msm->paSceneColor.b;

    // add invarient per-light per-material cached ambient

    for (lsm = gc->light.sources; lsm; lsm = lsm->next)
    {
        lspmm = &lsm->front + face;
        rsi += lspmm->ambient.r;
        gsi += lspmm->ambient.g;
        bsi += lspmm->ambient.b;
    }
    phong->invColor.r = rsi;
    phong->invColor.g = gsi;
    phong->invColor.b = bsi;
}

void FASTCALL __glGenericPickPhongProcs(__GLcontext *gc)
{
    __GLlightSourceMachine *lsm;
    GLboolean anySlow = GL_FALSE;
    GLboolean colorMaterial = (gc->state.enables.general & 
                               __GL_COLOR_MATERIAL_ENABLE);
    GLboolean rgb_mode = (gc->polygon.shader.modeFlags & __GL_SHADE_RGB);
    GLboolean normalize = (gc->state.enables.general & __GL_NORMALIZE_ENABLE);
    GLboolean doVanilla = GL_FALSE;
    
    gc->polygon.shader.phong.flags = 0;
    for (lsm = gc->light.sources; lsm; lsm = lsm->next) {
        if (lsm->slowPath) {
            anySlow = GL_TRUE;
            // Assuming here that anySlow means need Eye XPolate
            gc->polygon.shader.phong.flags |= __GL_PHONG_NEED_EYE_XPOLATE;
            break;
        }
    }
    
    doVanilla = (!(gc->state.enables.general & __GL_NORMALIZE_ENABLE)
                 || (anySlow)
                 || (gc->state.enables.general & __GL_POLYGON_SMOOTH_ENABLE)
                 || (gc->state.enables.general & __GL_LINE_SMOOTH_ENABLE)
        );
    
    
    if ((gc->state.hints.phong == GL_NICEST) || doVanilla)
    {
        gc->procs.phong.InitLineParams = InitLineParamsVan;
        
        if (anySlow)
        {
            gc->procs.phong.InitSpanInterpolation = InitSpanNEInterpolationVan;
            gc->procs.phong.UpdateAlongSpan = UpdateNEAlongSpanVan;
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorVanSlow;
            gc->procs.phong.ComputeCIColor = ComputeCIColorVanSlow;
        }
        else
        {
            gc->procs.phong.InitSpanInterpolation = InitSpanNInterpolationVan;
            gc->procs.phong.UpdateAlongSpan = UpdateNAlongSpanVan;
            gc->procs.phong.ComputeCIColor = ComputeCIColorVanFast;
            if (colorMaterial)
            {
                gc->procs.phong.ComputeRGBColor = ComputeRGBColorVanFast;
            }
            else
            {
                gc->procs.phong.ComputeRGBColor = ComputeRGBColorVanZippy;
            }
        }
    }
    else
    {
        ASSERTOPENGL (!anySlow, "Slow lights currently turned off\n");
        
        gc->procs.phong.InitSpanInterpolation = InitSpanInterpolationAccel;
        gc->procs.phong.UpdateAlongSpan = UpdateParamsAlongSpanAccel;
        gc->procs.phong.InitLineParams    = InitLineParamsAccel;
        gc->procs.phong.ComputeCIColor = ComputeCIColorAccelFast;
        
        if (colorMaterial)
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelFast;
        else
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelZippy;
        
    }
}

void __glCalcForwardDifferences( GLint w, __GLfloat p0, __GLfloat p1,
        __GLfloat p2, __GLfloat *d1, __GLfloat *d2 )
{
// Compute quadratic forward differences along a span of length w, from
// points p0, p1, p2
    __GLfloat dx;
    __GLfloat a0, a1, a2;

    if( w < 2 ) {
        *d1 = *d2 = 0.0f;
        return;
    }

    dx = 1.0f / w; // normalization factor

    // quadratic polynomial coefficients
    a0 = p0;
    a1 = ( -3.0f*p0 + 4.0f*p1 - p2) * dx;
    a2 = 2.0f * (p0 - 2.0f*p1 + p2) * dx * dx;

#ifdef __DEBUG_PRINT
    DbgPrint ("a2=%f, a1=%f, a0=%f\n", a2, a1, a0);
#endif
    // forward difference parameters
    *d1 = a1 + a2;
    *d2 = 2.0f * a2;
}



#ifdef __JUNKED_CODE
void InitSpanInterpolationFast (__GLcontext *gc)
{
    GLint i;
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    
    phong->tmp_pos.x = phong->cur_pos.x;
    phong->tmp_pos.y = phong->cur_pos.y;
    
    for (i=0; i<phong->numLights; i++)
    {
        __GLphongPerLightData *pld = &(phong->perLight[i]);
        
        /* Diffuse */
        pld->D_tmp = pld->D_curr;
        pld->Ddel_tmp = pld->DdelSpan;

        /* Specular */
        pld->S_tmp = pld->S_curr;
        pld->Sdel_tmp = pld->SdelSpan;
    }
}


#ifdef __TWO
        ASSERTOPENGL (!anySlow, "Slow lights currently turned off\n");

        gc->procs.phong.InitInterpolation = InitializePhongInterpolationVan;
        gc->procs.phong.SetInitParams = SetInitialPhongInterpolationVan;
        gc->procs.phong.UpdateAlongEdge = UpdateParamsAlongEdgeVan;
        
        gc->procs.phong.InitSpanInterpolation = InitSpanInterpolationTWO;
        gc->procs.phong.UpdateAlongSpan = UpdateParamsAlongSpanFast;
        
        //Line related
        gc->procs.phong.InitLineParams    = InitLineParamsFast;

        if (colorMaterial)
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelFast;
        else
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelZippy;
#else
        gc->procs.phong.InitInterpolation = InitializePhongInterpolationFast;
        gc->procs.phong.SetInitParams     = SetInitialPhongInterpolationFast;
        gc->procs.phong.UpdateAlongEdge   = UpdateParamsAlongEdgeFast;
        gc->procs.phong.InitSpanInterpolation = InitSpanInterpolationFast;
        gc->procs.phong.UpdateAlongSpan   = UpdateParamsAlongSpanFast;
        gc->procs.phong.ComputeCIColor    = ComputeCIColorAccelFast;

        //Line related
        gc->procs.phong.InitLineParams    = InitLineParamsFast;

        if (colorMaterial)
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelFast;
        else
            gc->procs.phong.ComputeRGBColor = ComputeRGBColorAccelZippy;
#endif

void InitSpanInterpolationTWO (__GLcontext *gc)
{
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    GLint face = phong->face;
    __GLlightSourceMachine *lsm;
    //__GLmaterialMachine *msm;
    __GLcoord n, dndx;
    __GLcoord *A = &dndx;
    __GLcoord *C = &n;
    __GLfloat a, b, c, d, e, f, g, h, i;   
    GLint curL;
    

    if (face == __GL_FRONTFACE)
    {
        //msm = &gc->light.front;
        n.x = phong->nCur.x;
        n.y = phong->nCur.y;
        n.z = phong->nCur.z;

        dndx.x = phong->dndx.x;
        dndx.y = phong->dndx.y;
        dndx.z = phong->dndx.z;
    }
    else
    {
        //msm = &gc->light.back;
        n.x = -phong->nCur.x;
        n.y = -phong->nCur.y;
        n.z = -phong->nCur.z;

        dndx.x = -phong->dndx.x;
        dndx.y = -phong->dndx.y;
        dndx.z = -phong->dndx.z;
    }
    
    if (gc->state.enables.general & __GL_NORMALIZE_ENABLE)
        __glNormalize(&n.x, &n.x);
    
    MAGN2 (d,A);                  //d = A.A 
    DOT   (g,A,C); g *= 2.0;      //g = 2A.C
    MAGN2 (i,C);                  //i = C.C

    for (lsm = gc->light.sources, curL=0; lsm; lsm = lsm->next, curL++)
    {
        __GLfloat i2, iRt, tmp5, tmp2;
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        __GLcoord *L = &(lsm->unitVPpli); // L is already normalized here
        __GLcoord *H = &(lsm->hHat);      // H is already normalized here
        
        i2 = (i*i);
        iRt = __GL_SQRTF(i);

        /***** Diffuse *****/
        // Remaining Bishop parameters
        DOT (a,L,A);              //a = L.A/|L|
        DOT (c,L,C);              //c = L.C/|L|

        tmp2 = (2.0*a*i - c*g)/(2.0*i*iRt);
        tmp5 = (3.0*c*g*g - 4.0*c*d*i - 4.0*a*g*i)/(8.0*i2*iRt);

        // Constant deltas
        pld->Ddel2Span = 2*tmp5;
        pld->Ddel_tmp = tmp2 + tmp5;
        pld->D_tmp = c/iRt;

        /***** Specular ******/
        // Remaining Bishop parameters
        DOT (a,H,A);              //a = H.A/|H|
        DOT (c,H,C);              //c = H.C/|H|

        // Polynomial coefficients
        tmp2 = (2.0*a*i - c*g)/(2.0*i*iRt);
        tmp5 = (3.0*c*g*g - 4.0*c*d*i - 4.0*a*g*i)/(8.0*i2*iRt);

        // Constant deltas
        pld->Sdel2Span = 2*tmp5;
        pld->Sdel_tmp = tmp2 + tmp5;
        pld->S_tmp = c/iRt;
    }
    phong->numLights = curL;
}

void SetInitialPhongInterpolationVan (__GLcontext *gc, __GLvertex *a, 
                                       __GLcoord *an, __GLfloat dx, 
                                       __GLfloat dy)
{
    __GLshade *sh = &gc->polygon.shader;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    __GLfloat little = sh->dxLeftLittle;
    __GLfloat big = sh->dxLeftBig;

    phong->nCur.x = an->x + dx*phong->dndx.x + dy*phong->dndy.x;
    phong->nCur.y = an->y + dx*phong->dndx.y + dy*phong->dndy.y;
    phong->nCur.z = an->z + dx*phong->dndx.z + dy*phong->dndy.z;

    phong->nLittle.x = phong->dndy.x + little * phong->dndx.x;
    phong->nLittle.y = phong->dndy.y + little * phong->dndx.y;
    phong->nLittle.z = phong->dndy.z + little * phong->dndx.z;

    if (big > little) 
    {
        phong->nBig.x = phong->nLittle.x + phong->dndx.x;
        phong->nBig.y = phong->nLittle.y + phong->dndx.y;
        phong->nBig.z = phong->nLittle.z + phong->dndx.z;
    }
    else
    {
        phong->nBig.x = phong->nLittle.x - phong->dndx.x;
        phong->nBig.y = phong->nLittle.y - phong->dndx.y;
        phong->nBig.z = phong->nLittle.z - phong->dndx.z;
    }

    if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        phong->eCur.x = a->eyeX + dx*phong->dedx.x + dy*phong->dedy.x;
        phong->eCur.y = a->eyeY + dx*phong->dedx.y + dy*phong->dedy.y;
        phong->eCur.z = a->eyeZ + dx*phong->dedx.z + dy*phong->dedy.z;
        phong->eCur.w = a->eyeW + dx*phong->dedx.w + dy*phong->dedy.w;

        phong->eLittle.x = phong->dedy.x + little * phong->dedx.x;
        phong->eLittle.y = phong->dedy.y + little * phong->dedx.y;
        phong->eLittle.z = phong->dedy.z + little * phong->dedx.z;
        phong->eLittle.w = phong->dedy.w + little * phong->dedx.w;

        if (big > little) 
        {
            phong->eBig.x = phong->eLittle.x + phong->dedx.x;
            phong->eBig.y = phong->eLittle.y + phong->dedx.y;
            phong->eBig.z = phong->eLittle.z + phong->dedx.z;
            phong->eBig.w = phong->eLittle.w + phong->dedx.w;
        }
        else
        {
            phong->eBig.x = phong->eLittle.x - phong->dedx.x;
            phong->eBig.y = phong->eLittle.y - phong->dedx.y;
            phong->eBig.z = phong->eLittle.z - phong->dedx.z;
            phong->eBig.w = phong->eLittle.w - phong->dedx.w;
        }
    }
}

/* Equivalent to SetInitialPhongParameters. Does for D and S */
void SetInitialPhongInterpolationFast (__GLcontext *gc, __GLvertex *a, 
                                       __GLcoord *an, __GLfloat dx, 
                                       __GLfloat dy)
{
    __GLshade *sh = &gc->polygon.shader;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    __GLfloat little = sh->dxLeftLittle;
    __GLfloat little2 = little*little;
    __GLfloat big = sh->dxLeftBig;
    __GLfloat big2 = big*big;
    __GLfloat dx2 = dx*dx;
    __GLfloat dy2 = dy*dy;
    __GLcoord pos;
    int i;
    GLfloat x, x2, y, y2;
    GLfloat aa, b, c, d, e, f, g, h, ii;

    phong->cur_pos.x += dx;
    phong->cur_pos.y += dy;
    pos = phong->cur_pos;
    x = phong->cur_pos.x; x2 = x*x;
    y = phong->cur_pos.y; y2 = y*y;
    
    for (i = 0; i<phong->numLights; i++)
    {
        __GLphongPerLightData *pld = &phong->perLight[i];
        __GLfloat tmp1, tmp2, tmp3;

        /**** Diffuse Parameters *****/
        pld->D_curr = pld->D[5]*x2 + pld->D[4]*x*y + pld->D[3]*y2 + 
                      pld->D[2]*x + pld->D[1]*y + pld->D[0];

        tmp1 = 2*pld->D[5]*x + pld->D[4]*y + pld->D[2];
        tmp2 = 2*pld->D[3]*y + pld->D[4]*x + pld->D[1];

        // Compute the along-edge del2 and del terms (Little)
        tmp3 = pld->D[5]*little2 + pld->D[4]*little + pld->D[3];
        pld->Ddel2EdgeLittle =  2*tmp3;
        pld->DdelEdgeLittle =  tmp1*little + tmp2 + tmp3;

        // Compute the along-edge del2 and del terms (Big)
        tmp3 =  pld->D[5]*big2 + pld->D[4]*big + pld->D[3];
        pld->Ddel2EdgeBig =  2*tmp3;
        pld->DdelEdgeBig =  tmp1*big + tmp2 + tmp3;

        // Compute the along-span del terms
        pld->DdelSpan = tmp1 + pld->D[5];
        pld->DdelSpanEdgeBig = pld->D[4] + 2*pld->D[5]*big;
        pld->DdelSpanEdgeLittle = pld->D[4] + 2*pld->D[5]*little;
        
        /**** Specular Parameters ****/
#ifndef __SLOW
        pld->S_curr = pld->S[5]*x2 + pld->S[4]*x*y + pld->S[3]*y2 + 
                      pld->S[2]*x + pld->S[1]*y + pld->S[0];
#else
        aa = pld->A[0]; b = pld->A[1];
        c = pld->A[2]; d = pld->A[3];
        e = pld->A[4]; f = pld->A[5];
        g = pld->A[6]; h = pld->A[7];
        ii = pld->A[8];
        
        pld->S_curr = (aa*x+b*y+c)/__GL_SQRTF(d*x2+e*x*y+f*y2+g*x+h*y+ii);

#endif

        tmp1 = 2*pld->S[5]*x + pld->S[4]*y + pld->S[2];
        tmp2 = 2*pld->S[3]*y + pld->S[4]*x + pld->S[1];

        // Compute the along-edge del2 and del terms (Little)
        tmp3 = pld->S[5]*little2 + pld->S[4]*little + pld->S[3];
        pld->Sdel2EdgeLittle =  2*tmp3;
        pld->SdelEdgeLittle =  tmp1*little + tmp2 + tmp3;

        // Compute the along-edge del2 and del terms (Big)
        tmp3 =  pld->S[5]*big2 + pld->S[4]*big + pld->S[3];
        pld->Sdel2EdgeBig =  2*tmp3;
        pld->SdelEdgeBig =  tmp1*big + tmp2 + tmp3;

        // Compute the along-span del terms
        pld->SdelSpan = tmp1 + pld->S[5];
        pld->SdelSpanEdgeBig = pld->S[4] + 2*pld->S[5]*big;
        pld->SdelSpanEdgeLittle = pld->S[4] + 2*pld->S[5]*little;
        
    }
}


/* Called when: Normalization Enabled, FastLights */
/******************************************************
 ****Set up the Polynomial for diffuse illumination****
 ******************************************************
 *                                                    *
 *                2              2                    *
 * SD (x,y) = D_5x + D_4xy + D_3y + D_2x + D_1y + D_0 *
 *                                                    *
 * D_i are expressed in terms of: a,b,c,d,e,f,g,h,i   *
 *                                                    *
 * D_0 = c/sqrt(i)                                    *
 * D_1 = (2bi - ch)/(2i*sqrt(i))                      *
 * D_2 = (2ai - cg)/(2i*sqrt(i))                      *
 * D_3 = (3ch^2 - 4cfi - 4bhi)/(4i^2*sqrt(i))         *
 * D_4 = (3cgh - 2ci - 2bgi - 2ahi)/(8i^2*sqrt(i))    *
 * D_5 = (3ig^2 - 4cdi - 4agi)/(4i^2*sqrt(i))         *
 ******************************************************/
void InitializePhongInterpolationFast (__GLcontext *gc, __GLvertex *v)
{
    GLboolean colorMaterial = (gc->state.enables.general & 
                               __GL_COLOR_MATERIAL_ENABLE);
    GLint face = gc->polygon.shader.phong.face;
    __GLlightSourcePerMaterialMachine *lspmm;
    __GLlightSourceMachine *lsm;
    __GLmaterialMachine *msm;
    GLuint msm_colorMaterialChange;
    __GLfloat msm_alpha;
    __GLfloat rsi, gsi, bsi;
    __GLcoord normal;
    GLint curL;
    __GLphongShader *phong = &gc->polygon.shader.phong;
    __GLshade *sh = &gc->polygon.shader;
    __GLfloat little = sh->dxLeftLittle;
    __GLfloat big = sh->dxLeftBig;
    __GLcoord *A = &(phong->dndx);
    __GLcoord *B = &(phong->dndy);
    __GLcoord *C;
    //From Bishop's paper
    __GLfloat a, b, c, d, e, f, g, h, i;   

#ifdef __CENTER
    normal.x = v->normal.x + (v->window.x - phong->center.x)*A->x 
                           + (v->window.y - phong->center.y)*B->x;
    normal.y = v->normal.y + (v->window.x - phong->center.x)*A->y
                           + (v->window.y - phong->center.y)*B->y;
    normal.z = v->normal.z + (v->window.x - phong->center.x)*A->z
                           + (v->window.y - phong->center.y)*B->z;
#else
    normal.x = v->normal.x;
    normal.y = v->normal.y;
    normal.z = v->normal.z;
#endif
    if (face == __GL_FRONTFACE)
    {
        msm = &gc->light.front;
    }
    else
    {
        msm = &gc->light.back;
        normal.x = -normal.x;
        normal.y = -normal.y;
        normal.z = -normal.z;
    }
    
    C = &normal;
    //msm_colorMaterialChange = msm->colorMaterialChange;
#ifdef __DBG_PRINT
    DbgPrint ("A = (%f, %f, %f)\n", A->x, A->y, A->z);
    DbgPrint ("B = (%f, %f, %f)\n", B->x, B->y, B->z);
    DbgPrint ("C = (%f, %f, %f)\n", C->x, C->y, C->z);
#endif
    
    //***********Diffuse Bishop Parameters*****************************
    //a, b, c depend upon the light vector, so compute inside the loop
    //d, e, f, g, h, i depend only upon the incoming normal
    
    MAGN2 (d, A);                 //d = A.A 
    DOT   (e,A,B); e *= 2.0;      //e = 2A.B
    MAGN2 (f, B);                 //f = B.B
    DOT   (g,A,C); g *= 2.0;      //g = 2A.C
    DOT   (h,B,C); h *= 2.0;      //h = 2B.C
    MAGN2 (i,C);                  //i = C.C

    // Normalization not needed since 
    // it was done (if needed) during normal propagation.
    // Compute the per-light interpolation parameters 
    
    for (lsm = gc->light.sources, curL = 0; lsm; 
         lsm = lsm->next, curL++)
    {
        __GLphongPerLightData *pld = &(phong->perLight[curL]);
        __GLcoord *L = &(lsm->unitVPpli); // L is already normalized here
        __GLcoord *H = &(lsm->hHat);      // H is already normalized here
        GLfloat i2, iRt;
        
        i2 = i*i;
        iRt = __GL_SQRTF(i);
        
        /***** Diffuse *****/
        // Remaining Bishop parameters
        DOT (a,L,A);              //a = L.A/|L|
        DOT (b,L,B);              //b = L.B/|L|
        DOT (c,L,C);              //c = L.C/|L|


        // Polynomial coefficients
        //DOT (pld->D[0], &normal, L);
        pld->D[0] = c/iRt;
        pld->D[1] = (2.0*b*i - c*h)/(2.0*i*iRt);
        pld->D[2] = (2.0*a*i - c*g)/(2.0*i*iRt);
        pld->D[3] = (3.0*c*h*h - 4.0*c*f*i - 4.0*b*h*i)/(8.0*i2*iRt);
        pld->D[4] = (3.0*c*g*h - 2.0*c*e*i - 2.0*b*g*i - 2.0*a*h*i)/
                    (4.0*i2*iRt);
        pld->D[5] = (3.0*c*g*g - 4.0*c*d*i - 4.0*a*g*i)/(8.0*i2*iRt);

#ifdef __DBG_PRINT
        DbgPrint ("D[0]= %f, D[1]=%f, D[2]=%f, D[3]=%f, D[4]=%f, D[5]=%f\n",
                  pld->D[0], pld->D[1], pld->D[2], pld->D[3], pld->D[4], 
                  pld->D[5]);
#endif
        // Constant deltas
        pld->Ddel2Span = 2*pld->D[5];
        pld->D_curr = pld->D[0];
#ifdef __DBG_PRINT
        DbgPrint ("Ddel2Span= %f, D_curr=%f\n", pld->Ddel2Span, pld->D_curr);
#endif

        /***** Specular ******/
        // Remaining Bishop parameters
        DOT (a,H,A);              //a = H.A/|H|
        DOT (b,H,B);              //b = H.B/|H|
        DOT (c,H,C);              //c = H.C/|H|

        // Polynomial coefficients
        DOT (pld->S[0], &normal, H);
        pld->S[1] = (2.0*b*i - c*h)/(2.0*i*iRt);
        pld->S[2] = (2.0*a*i - c*g)/(2.0*i*iRt);
        pld->S[3] = (3.0*c*h*h - 4.0*c*f*i - 4.0*b*h*i)/(8.0*i2*iRt);
        pld->S[4] = (3.0*c*g*h - 2.0*c*e*i - 2.0*b*g*i - 2.0*a*h*i)/
                    (4.0*i2*iRt);
        pld->S[5] = (3.0*c*g*g - 4.0*c*d*i - 4.0*a*g*i)/(8.0*i2*iRt);

        // Constant deltas
        pld->Sdel2Span = 2*pld->S[5];
        pld->S_curr = pld->S[0];

#ifdef __SLOW
        pld->A[0] = a; pld->A[1] = b;
        pld->A[2] = c; pld->A[3] = d;
        pld->A[4] = e; pld->A[5] = f;
        pld->A[6] = g; pld->A[7] = h;
        pld->A[8] = i; 
#endif        
#ifdef __DBG_PRINT
        DbgPrint ("L = (%f, %f, %f)\n", L->x, L->y, L->z);
        DbgPrint ("H = (%f, %f, %f)\n", H->x, H->y, H->z);
        DbgPrint ("a= %f, b=%f, c=%f, d=%f, e=%f, f=%f, g=%f, h=%f, i=%f\n",
                  a, b, c, d, e, f, g, h, i);
#endif
    }

    phong->numLights = curL;
#ifdef __CENTER
    phong->cur_pos.x = v->window.x - phong->center.x;
    phong->cur_pos.y = v->window.y - phong->center.y;
#else
    phong->cur_pos.x = 0.0;
    phong->cur_pos.y = 0.0;
#endif
}


void InitializePhongInterpolationSlow (__GLcontext *gc, __GLvertex *v)
{
}

/* Do nothing */
void InitializePhongInterpolationVan (__GLcontext *gc, __GLvertex *v)
{
    __GLphongShader *phong = &gc->polygon.shader.phong;

#ifdef __DBG_PRINT
    DbgPrint ("dndx = (%f, %f, %f)\n", phong->dndx.x, phong->dndx.y, 
                                       phong->dndx.z);
    DbgPrint ("dndy = (%f, %f, %f)\n", phong->dndy.x, phong->dndy.y, 
                                       phong->dndy.z);
    DbgPrint ("normal = (%f, %f, %f)\n", v->normal.x, v->normal.y, 
                                         v->normal.z);
#endif
}

void UpdateParamsAlongEdgeFast (__GLcontext *gc, __GLfloat dxLeft, 
                                GLboolean useBigStep)
{
    __GLphongShader *phong = &(gc->polygon.shader.phong);
    __GLphongPerLightData *pld;
    GLint i;

    if (useBigStep)
    {
        for (i=0; i<phong->numLights; i++)
        {
            pld = &(phong->perLight[i]);

            /** Diffuse Parameters **/
            pld->D_curr += pld->DdelEdgeBig;
            pld->DdelEdgeBig += pld->Ddel2EdgeBig;
            pld->DdelEdgeLittle += pld->Ddel2EdgeBig;
            pld->DdelSpan += pld->DdelSpanEdgeBig;

            /** Specular Parameters **/
            pld->S_curr += pld->SdelEdgeBig;
            pld->SdelEdgeBig += pld->Sdel2EdgeBig;
            pld->SdelEdgeLittle += pld->Sdel2EdgeBig;
            pld->SdelSpan += pld->SdelSpanEdgeBig;
        }
    }
    else //Use small step
    {
        for (i=0; i<phong->numLights; i++)
        {
            pld = &(phong->perLight[i]);

            /** Diffuse Parameters **/
            pld->D_curr += pld->DdelEdgeLittle;
            pld->DdelEdgeBig += pld->Ddel2EdgeLittle;
            pld->DdelEdgeLittle += pld->Ddel2EdgeLittle;
            pld->DdelSpan += pld->DdelSpanEdgeLittle;

            /** Specular Parameters **/
            pld->S_curr += pld->SdelEdgeLittle;
            pld->SdelEdgeBig += pld->Sdel2EdgeLittle;
            pld->SdelEdgeLittle += pld->Sdel2EdgeLittle;
            pld->SdelSpan += pld->SdelSpanEdgeLittle;
        }
    }

    phong->cur_pos.x += dxLeft;
    phong->cur_pos.y += 1.0;
}



void UpdateParamsAlongEdgeVan (__GLcontext *gc, __GLfloat dxLeft, 
                                GLboolean useBigStep)
{
    __GLphongShader *phong = &(gc->polygon.shader.phong);

    if (useBigStep)
    {
        phong->nCur.x += phong->nBig.x;
        phong->nCur.y += phong->nBig.y;
        phong->nCur.z += phong->nBig.z;
    }
    else
    {
        phong->nCur.x += phong->nLittle.x;
        phong->nCur.y += phong->nLittle.y;
        phong->nCur.z += phong->nLittle.z;
    }

    if (phong->flags & __GL_PHONG_NEED_EYE_XPOLATE)
    {
        if (useBigStep)
        {
            phong->eCur.x += phong->eBig.x;
            phong->eCur.y += phong->eBig.y;
            phong->eCur.z += phong->eBig.z;
            phong->eCur.w += phong->eBig.w;
        }
        else
        {
            phong->eCur.x += phong->eLittle.x;
            phong->eCur.y += phong->eLittle.y;
            phong->eCur.z += phong->eLittle.z;
            phong->eCur.w += phong->eLittle.w;
        }
    }
}


#endif //__JUNKED_CODE

#endif // GL_WIN_phong_shading