Source code of Windows XP (NT5)
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/*
** Copyright 1991, Silicon Graphics, Inc.
** All Rights Reserved.
**
** This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics, Inc.;
** the contents of this file may not be disclosed to third parties, copied or
** duplicated in any form, in whole or in part, without the prior written
** permission of Silicon Graphics, Inc.
**
** RESTRICTED RIGHTS LEGEND:
** Use, duplication or disclosure by the Government is subject to restrictions
** as set forth in subdivision (c)(1)(ii) of the Rights in Technical Data
** and Computer Software clause at DFARS 252.227-7013, and/or in similar or
** successor clauses in the FAR, DOD or NASA FAR Supplement. Unpublished -
** rights reserved under the Copyright Laws of the United States.
**
** $Revision: 1.4 $
** $Date: 1993/07/27 17:42:12 $
*/
#include "precomp.h"
#pragma hdrstop
/*
** A simple few routines which saves a cache for specular and spotlight
** computation (rather than recomputing the tables every time the user
** changes the specular or spotlight exponents).
*/
/*
** Any more than TOO_MANY_LUT_ENTRIES entries, and we free any that
** become unreferenced.
*/
#define TOO_MANY_LUT_ENTRIES 32
typedef struct {
__GLfloat exp;
__GLspecLUTEntry *table;
} __GLspecLUTEntryPtr;
typedef struct __GLspecLUTCache_Rec {
GLint nentries;
GLint allocatedSize;
__GLspecLUTEntryPtr entries[1];
} __GLspecLUTCache;
void FASTCALL __glInitLUTCache(__GLcontext *gc)
{
__GLspecLUTCache *lutCache;
lutCache = gc->light.lutCache = (__GLspecLUTCache *)
GCALLOC(gc, sizeof(__GLspecLUTCache));
#ifdef NT
if (!lutCache)
return;
#endif // NT
lutCache->nentries = 0;
lutCache->allocatedSize = 1;
}
void FASTCALL __glFreeLUTCache(__GLcontext *gc)
{
int i;
GLint nentries;
__GLspecLUTEntryPtr *entry;
__GLspecLUTCache *lutCache;
lutCache = gc->light.lutCache;
#ifdef NT
if (!lutCache)
return;
#endif // NT
nentries = lutCache->nentries;
for (i = 0; i < nentries; i++) {
entry = &(lutCache->entries[i]);
GCFREE(gc, entry->table);
}
GCFREE(gc, lutCache);
}
static __GLspecLUTEntry *findEntry(__GLspecLUTCache *lutCache, __GLfloat exp,
GLint *location)
{
GLint nentries;
GLint bottom, half, top;
__GLspecLUTEntry *table;
__GLspecLUTEntryPtr *entry;
#ifdef NT
ASSERTOPENGL(lutCache != NULL, "No LUT cache\n");
#endif // NT
nentries = lutCache->nentries;
/* First attempt to find this entry in our cache */
bottom = 0;
top = nentries;
while (top > bottom) {
/* Entry might exist in the range [bottom, top-1] */
half = (bottom+top)/2;
entry = &(lutCache->entries[half]);
if (entry->exp == exp) {
/* Found the table already cached! */
table = entry->table;
*location = half;
return table;
}
if (exp < entry->exp) {
/* exp might exist somewhere earlier in the table */
top = half;
} else /* exp > entry->exp */ {
/* exp might exist somewhere later in the table */
bottom = half+1;
}
}
*location = bottom;
return NULL;
}
__GLspecLUTEntry *__glCreateSpecLUT(__GLcontext *gc, __GLfloat exp)
{
GLint nentries, allocatedSize;
GLint location;
__GLspecLUTCache *lutCache;
__GLspecLUTEntryPtr *entry;
__GLspecLUTEntry *table;
__GLfloat *tableEntry;
GLdouble threshold, scale, x, dx;
GLint i;
/* This code uses double-precision math, so make sure that the FPU */
/* is set properly: */
FPU_SAVE_MODE();
FPU_CHOP_OFF_PREC_HI();
lutCache = gc->light.lutCache;
#ifdef NT
if (!lutCache)
return (__GLspecLUTEntry *)NULL;
#endif // NT
if (table = findEntry(lutCache, exp, &location)) {
table->refcount++;
return table;
}
/*
** We failed to find our entry in our cache anywhere, and have to compute
** it.
*/
lutCache->nentries = nentries = 1 + lutCache->nentries;
allocatedSize = lutCache->allocatedSize;
if (nentries > allocatedSize) {
/* Allocate space for another six entries (arbitrarily) */
lutCache->allocatedSize = allocatedSize = allocatedSize + 6;
if (!(lutCache = (__GLspecLUTCache *)
GCREALLOC(gc, lutCache, sizeof(__GLspecLUTCache) +
allocatedSize * sizeof(__GLspecLUTEntryPtr))))
{
gc->light.lutCache->allocatedSize -= 6;
gc->light.lutCache->nentries -= 1;
return (__GLspecLUTEntry *)NULL;
}
gc->light.lutCache = lutCache;
}
/*
** We have enough space now. So we stick the new entry in the array
** at entry 'location'. The rest of the entries need to be moved up
** (move [location, nentries-2] up to [location+1, nentries-1]).
*/
if (nentries-location-1) {
#ifdef NT
__GL_MEMMOVE(&(lutCache->entries[location+1]),
&(lutCache->entries[location]),
(nentries-location-1) * sizeof(__GLspecLUTEntryPtr));
#else
__GL_MEMCOPY(&(lutCache->entries[location+1]),
&(lutCache->entries[location]),
(nentries-location-1) * sizeof(__GLspecLUTEntryPtr));
#endif
}
entry = &(lutCache->entries[location]);
entry->exp = exp;
table = entry->table = (__GLspecLUTEntry *)
GCALLOC(gc, sizeof(__GLspecLUTEntry));
#ifdef NT
if (!table)
return (__GLspecLUTEntry *)NULL;
#endif // NT
/* Compute threshold */
if (exp == (__GLfloat) 0.0) {
threshold = (GLdouble) 0.0;
} else {
#ifdef NT
// Changing this enabled conformance to pass for color index visuals
// with 4096 colors, and did not seem to affect anything else.
// What this does is sort of reduce the granularity at the beginning
// of the table, because without it we were getting too big a jump
// between 0 and the first entry in the table, causing l_sen.c to fail.
threshold = (GLdouble) __GL_POWF((__GLfloat) 0.0005, (__GLfloat) 1.0 / exp);
#else
threshold = __GL_POWF(0.002, 1.0 / exp);
#endif
}
scale = (GLdouble) (__GL_SPEC_LOOKUP_TABLE_SIZE - 1) / ((GLdouble) 1.0 - threshold);
dx = (GLdouble) 1.0 / scale;
x = threshold;
tableEntry = table->table;
for (i = __GL_SPEC_LOOKUP_TABLE_SIZE; --i >= 0; ) {
*tableEntry++ = __GL_POWF(x, exp);
x += dx;
}
table->threshold = threshold;
table->scale = scale;
table->refcount = 1;
table->exp = exp;
FPU_RESTORE_MODE();
return table;
}
void FASTCALL __glFreeSpecLUT(__GLcontext *gc, __GLspecLUTEntry *lut)
{
__GLspecLUTCache *lutCache;
GLint location, nentries;
__GLspecLUTEntry *table;
if (lut == NULL) return;
ASSERTOPENGL(lut->refcount != 0, "Invalid refcount\n");
lut->refcount--;
if (lut->refcount > 0) return;
lutCache = gc->light.lutCache;
#ifdef NT
ASSERTOPENGL(lutCache != NULL, "No LUT cache\n");
#endif // NT
table = findEntry(lutCache, lut->exp, &location);
ASSERTOPENGL(table == lut, "Wrong LUT found\n");
if (table->refcount == 0 && lutCache->nentries >= TOO_MANY_LUT_ENTRIES) {
/*
** Free entry 'location'.
** This requires reducing lutCache->nentries by one, and copying
** entries [location+1, nentries] to [location, nentries-1].
*/
lutCache->nentries = nentries = lutCache->nentries - 1;
#ifdef NT
__GL_MEMMOVE(&(lutCache->entries[location]),
&(lutCache->entries[location+1]),
(nentries-location) * sizeof(__GLspecLUTEntryPtr));
#else
__GL_MEMCOPY(&(lutCache->entries[location]),
&(lutCache->entries[location+1]),
(nentries-location) * sizeof(__GLspecLUTEntryPtr));
#endif
GCFREE(gc, table);
}
}