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570 lines
14 KiB
570 lines
14 KiB
/**************************************************************************
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* *
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* Copyright (C) 1992, Silicon Graphics, Inc. *
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* *
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* These coded instructions, statements, and computer programs contain *
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* unpublished proprietary information of Silicon Graphics, Inc., and *
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* are protected by Federal copyright law. They may not be disclosed *
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* to third parties or copied or duplicated in any form, in whole or *
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* in part, without the prior written consent of Silicon Graphics, Inc. *
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* *
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**************************************************************************/
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/*
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* intersect.c++ - $Revision: 1.5 $
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* Derrick Burns - 1991
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*/
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#include "glimport.h"
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#include "myassert.h"
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#include "mystdio.h"
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#include "subdivid.h"
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#include "arc.h"
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#include "bin.h"
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#include "backend.h"
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#include "trimpool.h"
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enum i_result { INTERSECT_VERTEX, INTERSECT_EDGE };
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/* local functions */
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static int arc_classify( Arc_ptr, int, REAL );
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static enum i_result pwlarc_intersect( PwlArc *, int, REAL, int, int[3] );
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void
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Subdivider::partition( Bin & bin, Bin & left, Bin & intersections,
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Bin & right, Bin & unknown, int param, REAL value )
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{
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Bin headonleft, headonright, tailonleft, tailonright;
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for( Arc_ptr jarc = bin.removearc(); jarc; jarc = bin.removearc() ) {
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REAL tdiff = jarc->tail()[param] - value;
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REAL hdiff = jarc->head()[param] - value;
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if( tdiff > 0.0 ) {
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if( hdiff > 0.0 ) {
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right.addarc( jarc );
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} else if( hdiff == 0.0 ) {
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tailonright.addarc( jarc );
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} else {
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Arc_ptr jtemp;
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switch( arc_split(jarc, param, value, 0) ) {
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case 2:
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tailonright.addarc( jarc );
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headonleft.addarc( jarc->next );
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break;
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case 31:
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assert( jarc->head()[param] > value );
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right.addarc( jarc );
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tailonright.addarc( jtemp = jarc->next );
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headonleft.addarc( jtemp->next );
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break;
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case 32:
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assert( jarc->head()[param] <= value );
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tailonright .addarc( jarc );
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headonleft.addarc( jtemp = jarc->next );
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left.addarc( jtemp->next );
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break;
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case 4:
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right.addarc( jarc );
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tailonright.addarc( jtemp = jarc->next );
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headonleft.addarc( jtemp = jtemp->next );
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left.addarc( jtemp->next );
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}
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}
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} else if( tdiff == 0.0 ) {
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if( hdiff > 0.0 ) {
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headonright.addarc( jarc );
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} else if( hdiff == 0.0 ) {
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unknown.addarc( jarc );
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} else {
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headonleft.addarc( jarc );
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}
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} else {
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if( hdiff > 0.0 ) {
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Arc_ptr jtemp;
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switch( arc_split(jarc, param, value, 1) ) {
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case 2:
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tailonleft.addarc( jarc );
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headonright.addarc( jarc->next );
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break;
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case 31:
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assert( jarc->head()[param] < value );
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left.addarc( jarc );
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tailonleft.addarc( jtemp = jarc->next );
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headonright.addarc( jtemp->next );
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break;
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case 32:
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assert( jarc->head()[param] >= value );
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tailonleft.addarc( jarc );
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headonright.addarc( jtemp = jarc->next );
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right.addarc( jtemp->next );
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break;
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case 4:
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left.addarc( jarc );
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tailonleft.addarc( jtemp = jarc->next );
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headonright.addarc( jtemp = jtemp->next );
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right.addarc( jtemp->next );
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}
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} else if( hdiff == 0.0 ) {
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tailonleft.addarc( jarc );
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} else {
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left.addarc( jarc );
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}
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}
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}
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if( param == 0 ) {
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classify_headonleft_s( headonleft, intersections, left, value );
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classify_tailonleft_s( tailonleft, intersections, left, value );
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classify_headonright_s( headonright, intersections, right, value );
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classify_tailonright_s( tailonright, intersections, right, value );
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} else {
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classify_headonleft_t( headonleft, intersections, left, value );
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classify_tailonleft_t( tailonleft, intersections, left, value );
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classify_headonright_t( headonright, intersections, right, value );
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classify_tailonright_t( tailonright, intersections, right, value );
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}
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}
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inline static void
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vert_interp( TrimVertex *n, TrimVertex *l, TrimVertex *r, int p, REAL val )
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{
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assert( val > l->param[p]);
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assert( val < r->param[p]);
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n->nuid = l->nuid;
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n->param[p] = val;
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if( l->param[1-p] != r->param[1-p] ) {
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REAL ratio = (val - l->param[p]) / (r->param[p] - l->param[p]);
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n->param[1-p] = l->param[1-p] +
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ratio * (r->param[1-p] - l->param[1-p]);
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} else {
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n->param[1-p] = l->param[1-p];
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}
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}
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int
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Subdivider::arc_split( Arc_ptr jarc, int param, REAL value, int dir )
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{
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int maxvertex = jarc->pwlArc->npts;
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Arc_ptr jarc1, jarc2, jarc3;
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TrimVertex* v = jarc->pwlArc->pts;
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int loc[3];
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switch( pwlarc_intersect( jarc->pwlArc, param, value, dir, loc ) ) {
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case INTERSECT_VERTEX: {
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jarc1 = new(arcpool) Arc( jarc, new( pwlarcpool) PwlArc( maxvertex-loc[1], &v[loc[1]] ) );
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jarc->pwlArc->npts = loc[1] + 1;
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jarc1->next = jarc->next;
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jarc1->next->prev = jarc1;
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jarc->next = jarc1;
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jarc1->prev = jarc;
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assert(jarc->check() != 0);
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return 2;
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}
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case INTERSECT_EDGE: {
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int i, j;
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if( dir == 0 ) {
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i = loc[0];
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j = loc[2];
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} else {
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i = loc[2];
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j = loc[0];
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}
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TrimVertex *newjunk = trimvertexpool.get(3);
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v[i].nuid = jarc->nuid;
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v[j].nuid = jarc->nuid;
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newjunk[0] = v[j];
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newjunk[2] = v[i];
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vert_interp( &newjunk[1], &v[loc[0]], &v[loc[2]], param, value );
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if( showingDegenerate() )
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backend.triangle( &newjunk[2], &newjunk[1], &newjunk[0] );
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if (maxvertex == 2) {
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jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
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jarc->pwlArc->npts = 2;
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jarc->pwlArc->pts = newjunk;
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jarc1->next = jarc->next;
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jarc1->next->prev = jarc1;
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jarc->next = jarc1;
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jarc1->prev = jarc;
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assert(jarc->check() != 0);
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return 2;
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} else if (maxvertex - j == 2) {
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jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
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jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
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jarc->pwlArc->npts = maxvertex-1;
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jarc2->next = jarc->next;
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jarc2->next->prev = jarc2;
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jarc->next = jarc1;
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jarc1->prev = jarc;
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jarc1->next = jarc2;
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jarc2->prev = jarc1;
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assert(jarc->check() != 0);
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return 31;
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} else if (i == 1) {
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jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
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jarc2 = new(arcpool) Arc( jarc,
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new(pwlarcpool) PwlArc( maxvertex-1, &jarc->pwlArc->pts[1] ) );
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jarc->pwlArc->npts = 2;
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jarc->pwlArc->pts = newjunk;
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jarc2->next = jarc->next;
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jarc2->next->prev = jarc2;
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jarc->next = jarc1;
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jarc1->prev = jarc;
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jarc1->next = jarc2;
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jarc2->prev = jarc1;
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assert(jarc->check() != 0);
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return 32;
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} else {
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jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
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jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
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jarc3 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( maxvertex-i, v+i ) );
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jarc->pwlArc->npts = j + 1;
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jarc3->next = jarc->next;
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jarc3->next->prev = jarc3;
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jarc->next = jarc1;
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jarc1->prev = jarc;
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jarc1->next = jarc2;
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jarc2->prev = jarc1;
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jarc2->next = jarc3;
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jarc3->prev = jarc2;
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assert(jarc->check() != 0);
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return 4;
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}
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}
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default:
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return -1; //picked -1 since it's not used
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}
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}
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/*----------------------------------------------------------------------------
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* pwlarc_intersect - find intersection of pwlArc and isoparametric line
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*----------------------------------------------------------------------------
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*/
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static enum i_result
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pwlarc_intersect(
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PwlArc *pwlArc,
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int param,
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REAL value,
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int dir,
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int loc[3] )
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{
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assert( pwlArc->npts > 0 );
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if( dir ) {
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TrimVertex *v = pwlArc->pts;
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int imin = 0;
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int imax = pwlArc->npts - 1;
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assert( value > v[imin].param[param] );
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assert( value < v[imax].param[param] );
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while( (imax - imin) > 1 ) {
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int imid = (imax + imin)/2;
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if( v[imid].param[param] > value )
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imax = imid;
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else if( v[imid].param[param] < value )
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imin = imid;
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else {
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loc[1] = imid;
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return INTERSECT_VERTEX;
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}
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}
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loc[0] = imin;
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loc[2] = imax;
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return INTERSECT_EDGE;
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} else {
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TrimVertex *v = pwlArc->pts;
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int imax = 0;
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int imin = pwlArc->npts - 1;
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assert( value > v[imin].param[param] );
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assert( value < v[imax].param[param] );
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while( (imin - imax) > 1 ) {
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int imid = (imax + imin)/2;
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if( v[imid].param[param] > value )
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imax = imid;
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else if( v[imid].param[param] < value )
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imin = imid;
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else {
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loc[1] = imid;
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return INTERSECT_VERTEX;
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}
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}
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loc[0] = imin;
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loc[2] = imax;
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return INTERSECT_EDGE;
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}
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}
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/*----------------------------------------------------------------------------
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* arc_classify - determine which side of a line a jarc lies
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*----------------------------------------------------------------------------
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*/
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static int
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arc_classify( Arc_ptr jarc, int param, REAL value )
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{
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REAL tdiff, hdiff;
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if( param == 0 ) {
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tdiff = jarc->tail()[0] - value;
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hdiff = jarc->head()[0] - value;
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} else {
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tdiff = jarc->tail()[1] - value;
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hdiff = jarc->head()[1] - value;
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}
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if( tdiff > 0.0 ) {
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if( hdiff > 0.0 ) {
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return 0x11;
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} else if( hdiff == 0.0 ) {
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return 0x12;
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} else {
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return 0x10;
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}
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} else if( tdiff == 0.0 ) {
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if( hdiff > 0.0 ) {
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return 0x21;
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} else if( hdiff == 0.0 ) {
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return 0x22;
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} else {
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return 0x20;
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}
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} else {
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if( hdiff > 0.0 ) {
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return 0x01;
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} else if( hdiff == 0.0 ) {
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return 0x02;
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} else {
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return 0;
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}
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}
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}
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void
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Subdivider::classify_tailonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail at left, head on line */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 0, val ) == 0x02 );
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j->clearitail();
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REAL diff = j->next->head()[0] - val;
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if( diff > 0.0 ) {
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in.addarc( j );
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} else if( diff < 0.0 ) {
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if( ccwTurn_sl( j, j->next ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else {
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if( j->next->tail()[1] > j->next->head()[1] )
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in.addarc(j);
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else
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out.addarc(j);
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}
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}
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}
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void
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Subdivider::classify_tailonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail at left, head on line */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 1, val ) == 0x02 );
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j->clearitail();
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REAL diff = j->next->head()[1] - val;
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if( diff > 0.0 ) {
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in.addarc( j );
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} else if( diff < 0.0 ) {
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if( ccwTurn_tl( j, j->next ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else {
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if (j->next->tail()[0] > j->next->head()[0] )
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out.addarc( j );
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else
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in.addarc( j );
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}
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}
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}
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void
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Subdivider::classify_headonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail on line, head at left */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 0, val ) == 0x20 );
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j->setitail();
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REAL diff = j->prev->tail()[0] - val;
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if( diff > 0.0 ) {
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out.addarc( j );
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} else if( diff < 0.0 ) {
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if( ccwTurn_sl( j->prev, j ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else {
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if( j->prev->tail()[1] > j->prev->head()[1] )
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in.addarc( j );
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else
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out.addarc( j );
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}
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}
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}
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void
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Subdivider::classify_headonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail on line, head at left */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 1, val ) == 0x20 );
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j->setitail();
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REAL diff = j->prev->tail()[1] - val;
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if( diff > 0.0 ) {
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out.addarc( j );
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} else if( diff < 0.0 ) {
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if( ccwTurn_tl( j->prev, j ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else {
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if( j->prev->tail()[0] > j->prev->head()[0] )
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out.addarc( j );
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else
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in.addarc( j );
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}
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}
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}
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void
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Subdivider::classify_tailonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail at right, head on line */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 0, val ) == 0x12);
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j->clearitail();
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REAL diff = j->next->head()[0] - val;
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if( diff > 0.0 ) {
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if( ccwTurn_sr( j, j->next ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else if( diff < 0.0 ) {
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in.addarc( j );
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} else {
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if( j->next->tail()[1] > j->next->head()[1] )
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out.addarc( j );
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else
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in.addarc( j );
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}
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}
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}
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void
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Subdivider::classify_tailonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
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{
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/* tail at right, head on line */
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Arc_ptr j;
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while( j = bin.removearc() ) {
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assert( arc_classify( j, 1, val ) == 0x12);
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j->clearitail();
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REAL diff = j->next->head()[1] - val;
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if( diff > 0.0 ) {
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if( ccwTurn_tr( j, j->next ) )
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out.addarc( j );
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else
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in.addarc( j );
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} else if( diff < 0.0 ) {
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in.addarc( j );
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} else {
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if( j->next->tail()[0] > j->next->head()[0] )
|
|
in.addarc( j );
|
|
else
|
|
out.addarc( j );
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
Subdivider::classify_headonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
|
|
{
|
|
/* tail on line, head at right */
|
|
Arc_ptr j;
|
|
|
|
while( j = bin.removearc() ) {
|
|
assert( arc_classify( j, 0, val ) == 0x21 );
|
|
|
|
j->setitail();
|
|
|
|
REAL diff = j->prev->tail()[0] - val;
|
|
if( diff > 0.0 ) {
|
|
if( ccwTurn_sr( j->prev, j ) )
|
|
out.addarc( j );
|
|
else
|
|
in.addarc( j );
|
|
} else if( diff < 0.0 ) {
|
|
out.addarc( j );
|
|
} else {
|
|
if( j->prev->tail()[1] > j->prev->head()[1] )
|
|
out.addarc( j );
|
|
else
|
|
in.addarc( j );
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
Subdivider::classify_headonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
|
|
{
|
|
/* tail on line, head at right */
|
|
Arc_ptr j;
|
|
|
|
while( j = bin.removearc() ) {
|
|
assert( arc_classify( j, 1, val ) == 0x21 );
|
|
|
|
j->setitail();
|
|
|
|
REAL diff = j->prev->tail()[1] - val;
|
|
if( diff > 0.0 ) {
|
|
if( ccwTurn_tr( j->prev, j ) )
|
|
out.addarc( j );
|
|
else
|
|
in.addarc( j );
|
|
} else if( diff < 0.0 ) {
|
|
out.addarc( j );
|
|
} else {
|
|
if( j->prev->tail()[0] > j->prev->head()[0] )
|
|
in.addarc( j );
|
|
else
|
|
out.addarc( j );
|
|
}
|
|
}
|
|
}
|
|
|