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Diffstat (limited to 'src/glu/sgi/libtess/geom.c')
| -rw-r--r-- | src/glu/sgi/libtess/geom.c | 264 |
1 files changed, 0 insertions, 264 deletions
diff --git a/src/glu/sgi/libtess/geom.c b/src/glu/sgi/libtess/geom.c deleted file mode 100644 index 35b36a394c4..00000000000 --- a/src/glu/sgi/libtess/geom.c +++ /dev/null @@ -1,264 +0,0 @@ -/* - * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) - * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved. - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice including the dates of first publication and - * either this permission notice or a reference to - * http://oss.sgi.com/projects/FreeB/ - * shall be included in all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS - * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, - * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF - * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE - * SOFTWARE. - * - * Except as contained in this notice, the name of Silicon Graphics, Inc. - * shall not be used in advertising or otherwise to promote the sale, use or - * other dealings in this Software without prior written authorization from - * Silicon Graphics, Inc. - */ -/* -** Author: Eric Veach, July 1994. -** -*/ - -#include "gluos.h" -#include <assert.h> -#include "mesh.h" -#include "geom.h" - -int __gl_vertLeq( GLUvertex *u, GLUvertex *v ) -{ - /* Returns TRUE if u is lexicographically <= v. */ - - return VertLeq( u, v ); -} - -GLdouble __gl_edgeEval( GLUvertex *u, GLUvertex *v, GLUvertex *w ) -{ - /* Given three vertices u,v,w such that VertLeq(u,v) && VertLeq(v,w), - * evaluates the t-coord of the edge uw at the s-coord of the vertex v. - * Returns v->t - (uw)(v->s), ie. the signed distance from uw to v. - * If uw is vertical (and thus passes thru v), the result is zero. - * - * The calculation is extremely accurate and stable, even when v - * is very close to u or w. In particular if we set v->t = 0 and - * let r be the negated result (this evaluates (uw)(v->s)), then - * r is guaranteed to satisfy MIN(u->t,w->t) <= r <= MAX(u->t,w->t). - */ - GLdouble gapL, gapR; - - assert( VertLeq( u, v ) && VertLeq( v, w )); - - gapL = v->s - u->s; - gapR = w->s - v->s; - - if( gapL + gapR > 0 ) { - if( gapL < gapR ) { - return (v->t - u->t) + (u->t - w->t) * (gapL / (gapL + gapR)); - } else { - return (v->t - w->t) + (w->t - u->t) * (gapR / (gapL + gapR)); - } - } - /* vertical line */ - return 0; -} - -GLdouble __gl_edgeSign( GLUvertex *u, GLUvertex *v, GLUvertex *w ) -{ - /* Returns a number whose sign matches EdgeEval(u,v,w) but which - * is cheaper to evaluate. Returns > 0, == 0 , or < 0 - * as v is above, on, or below the edge uw. - */ - GLdouble gapL, gapR; - - assert( VertLeq( u, v ) && VertLeq( v, w )); - - gapL = v->s - u->s; - gapR = w->s - v->s; - - if( gapL + gapR > 0 ) { - return (v->t - w->t) * gapL + (v->t - u->t) * gapR; - } - /* vertical line */ - return 0; -} - - -/*********************************************************************** - * Define versions of EdgeSign, EdgeEval with s and t transposed. - */ - -GLdouble __gl_transEval( GLUvertex *u, GLUvertex *v, GLUvertex *w ) -{ - /* Given three vertices u,v,w such that TransLeq(u,v) && TransLeq(v,w), - * evaluates the t-coord of the edge uw at the s-coord of the vertex v. - * Returns v->s - (uw)(v->t), ie. the signed distance from uw to v. - * If uw is vertical (and thus passes thru v), the result is zero. - * - * The calculation is extremely accurate and stable, even when v - * is very close to u or w. In particular if we set v->s = 0 and - * let r be the negated result (this evaluates (uw)(v->t)), then - * r is guaranteed to satisfy MIN(u->s,w->s) <= r <= MAX(u->s,w->s). - */ - GLdouble gapL, gapR; - - assert( TransLeq( u, v ) && TransLeq( v, w )); - - gapL = v->t - u->t; - gapR = w->t - v->t; - - if( gapL + gapR > 0 ) { - if( gapL < gapR ) { - return (v->s - u->s) + (u->s - w->s) * (gapL / (gapL + gapR)); - } else { - return (v->s - w->s) + (w->s - u->s) * (gapR / (gapL + gapR)); - } - } - /* vertical line */ - return 0; -} - -GLdouble __gl_transSign( GLUvertex *u, GLUvertex *v, GLUvertex *w ) -{ - /* Returns a number whose sign matches TransEval(u,v,w) but which - * is cheaper to evaluate. Returns > 0, == 0 , or < 0 - * as v is above, on, or below the edge uw. - */ - GLdouble gapL, gapR; - - assert( TransLeq( u, v ) && TransLeq( v, w )); - - gapL = v->t - u->t; - gapR = w->t - v->t; - - if( gapL + gapR > 0 ) { - return (v->s - w->s) * gapL + (v->s - u->s) * gapR; - } - /* vertical line */ - return 0; -} - - -int __gl_vertCCW( GLUvertex *u, GLUvertex *v, GLUvertex *w ) -{ - /* For almost-degenerate situations, the results are not reliable. - * Unless the floating-point arithmetic can be performed without - * rounding errors, *any* implementation will give incorrect results - * on some degenerate inputs, so the client must have some way to - * handle this situation. - */ - return (u->s*(v->t - w->t) + v->s*(w->t - u->t) + w->s*(u->t - v->t)) >= 0; -} - -/* Given parameters a,x,b,y returns the value (b*x+a*y)/(a+b), - * or (x+y)/2 if a==b==0. It requires that a,b >= 0, and enforces - * this in the rare case that one argument is slightly negative. - * The implementation is extremely stable numerically. - * In particular it guarantees that the result r satisfies - * MIN(x,y) <= r <= MAX(x,y), and the results are very accurate - * even when a and b differ greatly in magnitude. - */ -#define RealInterpolate(a,x,b,y) \ - (a = (a < 0) ? 0 : a, b = (b < 0) ? 0 : b, \ - ((a <= b) ? ((b == 0) ? ((x+y) / 2) \ - : (x + (y-x) * (a/(a+b)))) \ - : (y + (x-y) * (b/(a+b))))) - -#ifndef FOR_TRITE_TEST_PROGRAM -#define Interpolate(a,x,b,y) RealInterpolate(a,x,b,y) -#else - -/* Claim: the ONLY property the sweep algorithm relies on is that - * MIN(x,y) <= r <= MAX(x,y). This is a nasty way to test that. - */ -#include <stdlib.h> -extern int RandomInterpolate; - -GLdouble Interpolate( GLdouble a, GLdouble x, GLdouble b, GLdouble y) -{ -printf("*********************%d\n",RandomInterpolate); - if( RandomInterpolate ) { - a = 1.2 * drand48() - 0.1; - a = (a < 0) ? 0 : ((a > 1) ? 1 : a); - b = 1.0 - a; - } - return RealInterpolate(a,x,b,y); -} - -#endif - -#define Swap(a,b) do { GLUvertex *t = a; a = b; b = t; } while (0) - -void __gl_edgeIntersect( GLUvertex *o1, GLUvertex *d1, - GLUvertex *o2, GLUvertex *d2, - GLUvertex *v ) -/* Given edges (o1,d1) and (o2,d2), compute their point of intersection. - * The computed point is guaranteed to lie in the intersection of the - * bounding rectangles defined by each edge. - */ -{ - GLdouble z1, z2; - - /* This is certainly not the most efficient way to find the intersection - * of two line segments, but it is very numerically stable. - * - * Strategy: find the two middle vertices in the VertLeq ordering, - * and interpolate the intersection s-value from these. Then repeat - * using the TransLeq ordering to find the intersection t-value. - */ - - if( ! VertLeq( o1, d1 )) { Swap( o1, d1 ); } - if( ! VertLeq( o2, d2 )) { Swap( o2, d2 ); } - if( ! VertLeq( o1, o2 )) { Swap( o1, o2 ); Swap( d1, d2 ); } - - if( ! VertLeq( o2, d1 )) { - /* Technically, no intersection -- do our best */ - v->s = (o2->s + d1->s) / 2; - } else if( VertLeq( d1, d2 )) { - /* Interpolate between o2 and d1 */ - z1 = EdgeEval( o1, o2, d1 ); - z2 = EdgeEval( o2, d1, d2 ); - if( z1+z2 < 0 ) { z1 = -z1; z2 = -z2; } - v->s = Interpolate( z1, o2->s, z2, d1->s ); - } else { - /* Interpolate between o2 and d2 */ - z1 = EdgeSign( o1, o2, d1 ); - z2 = -EdgeSign( o1, d2, d1 ); - if( z1+z2 < 0 ) { z1 = -z1; z2 = -z2; } - v->s = Interpolate( z1, o2->s, z2, d2->s ); - } - - /* Now repeat the process for t */ - - if( ! TransLeq( o1, d1 )) { Swap( o1, d1 ); } - if( ! TransLeq( o2, d2 )) { Swap( o2, d2 ); } - if( ! TransLeq( o1, o2 )) { Swap( o1, o2 ); Swap( d1, d2 ); } - - if( ! TransLeq( o2, d1 )) { - /* Technically, no intersection -- do our best */ - v->t = (o2->t + d1->t) / 2; - } else if( TransLeq( d1, d2 )) { - /* Interpolate between o2 and d1 */ - z1 = TransEval( o1, o2, d1 ); - z2 = TransEval( o2, d1, d2 ); - if( z1+z2 < 0 ) { z1 = -z1; z2 = -z2; } - v->t = Interpolate( z1, o2->t, z2, d1->t ); - } else { - /* Interpolate between o2 and d2 */ - z1 = TransSign( o1, o2, d1 ); - z2 = -TransSign( o1, d2, d1 ); - if( z1+z2 < 0 ) { z1 = -z1; z2 = -z2; } - v->t = Interpolate( z1, o2->t, z2, d2->t ); - } -} |