2
** License Applicability. Except to the extent portions of this file are
3
** made subject to an alternative license as permitted in the SGI Free
4
** Software License B, Version 1.1 (the "License"), the contents of this
5
** file are subject only to the provisions of the License. You may not use
6
** this file except in compliance with the License. You may obtain a copy
7
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
8
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
10
** http://oss.sgi.com/projects/FreeB
12
** Note that, as provided in the License, the Software is distributed on an
13
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
14
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
15
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
16
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
18
** Original Code. The Original Code is: OpenGL Sample Implementation,
19
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
20
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
21
** Copyright in any portions created by third parties is as indicated
22
** elsewhere herein. All Rights Reserved.
24
** Additional Notice Provisions: The application programming interfaces
25
** established by SGI in conjunction with the Original Code are The
26
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
27
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
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** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
29
** Window System(R) (Version 1.3), released October 19, 1998. This software
30
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
31
** published by SGI, but has not been independently verified as being
32
** compliant with the OpenGL(R) version 1.2.1 Specification.
39
* $Header: //depot/main/gfx/lib/glu/libnurbs/internals/intersect.cc#3 $
42
#include "glimports.h"
45
#include "subdivider.h"
49
#include "trimvertpool.h"
53
enum i_result { INTERSECT_VERTEX, INTERSECT_EDGE };
56
static int arc_classify( Arc_ptr, int, REAL );
57
static enum i_result pwlarc_intersect( PwlArc *, int, REAL, int, int[3] );
61
Subdivider::partition( Bin & bin, Bin & left, Bin & intersections,
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Bin & right, Bin & unknown, int param, REAL value )
64
Bin headonleft, headonright, tailonleft, tailonright;
66
for( Arc_ptr jarc = bin.removearc(); jarc; jarc = bin.removearc() ) {
68
REAL tdiff = jarc->tail()[param] - value;
69
REAL hdiff = jarc->head()[param] - value;
74
} else if( hdiff == 0.0 ) {
75
tailonright.addarc( jarc );
78
switch( arc_split(jarc, param, value, 0) ) {
80
tailonright.addarc( jarc );
81
headonleft.addarc( jarc->next );
84
assert( jarc->head()[param] > value );
86
tailonright.addarc( jtemp = jarc->next );
87
headonleft.addarc( jtemp->next );
90
assert( jarc->head()[param] <= value );
91
tailonright .addarc( jarc );
92
headonleft.addarc( jtemp = jarc->next );
93
left.addarc( jtemp->next );
97
tailonright.addarc( jtemp = jarc->next );
98
headonleft.addarc( jtemp = jtemp->next );
99
left.addarc( jtemp->next );
102
} else if( tdiff == 0.0 ) {
104
headonright.addarc( jarc );
105
} else if( hdiff == 0.0 ) {
106
unknown.addarc( jarc );
108
headonleft.addarc( jarc );
113
switch( arc_split(jarc, param, value, 1) ) {
115
tailonleft.addarc( jarc );
116
headonright.addarc( jarc->next );
119
assert( jarc->head()[param] < value );
121
tailonleft.addarc( jtemp = jarc->next );
122
headonright.addarc( jtemp->next );
125
assert( jarc->head()[param] >= value );
126
tailonleft.addarc( jarc );
127
headonright.addarc( jtemp = jarc->next );
128
right.addarc( jtemp->next );
132
tailonleft.addarc( jtemp = jarc->next );
133
headonright.addarc( jtemp = jtemp->next );
134
right.addarc( jtemp->next );
136
} else if( hdiff == 0.0 ) {
137
tailonleft.addarc( jarc );
144
classify_headonleft_s( headonleft, intersections, left, value );
145
classify_tailonleft_s( tailonleft, intersections, left, value );
146
classify_headonright_s( headonright, intersections, right, value );
147
classify_tailonright_s( tailonright, intersections, right, value );
149
classify_headonleft_t( headonleft, intersections, left, value );
150
classify_tailonleft_t( tailonleft, intersections, left, value );
151
classify_headonright_t( headonright, intersections, right, value );
152
classify_tailonright_t( tailonright, intersections, right, value );
157
vert_interp( TrimVertex *n, TrimVertex *l, TrimVertex *r, int p, REAL val )
159
assert( val > l->param[p]);
160
assert( val < r->param[p]);
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if( l->param[1-p] != r->param[1-p] ) {
166
REAL ratio = (val - l->param[p]) / (r->param[p] - l->param[p]);
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n->param[1-p] = l->param[1-p] +
168
ratio * (r->param[1-p] - l->param[1-p]);
170
n->param[1-p] = l->param[1-p];
175
Subdivider::arc_split( Arc_ptr jarc, int param, REAL value, int dir )
177
int maxvertex = jarc->pwlArc->npts;
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Arc_ptr jarc1, jarc2, jarc3;
179
TrimVertex* v = jarc->pwlArc->pts;
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switch( pwlarc_intersect( jarc->pwlArc, param, value, dir, loc ) ) {
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// When the parameter value lands on a vertex, life is sweet
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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;
192
assert(jarc->check() != 0);
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// When the parameter value intersects an edge, we have to
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// interpolate a new vertex. There are special cases
198
// if the new vertex is adjacent to one or both of the
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// endpoints of the arc.
200
case INTERSECT_EDGE: {
211
// The split is between vertices at index j and i, in that
214
// JEB: This code is my idea of how to do the split without
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// increasing the number of links. I'm doing this so that
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// the is_rect routine can recognize rectangles created by
217
// subdivision. In exchange for simplifying the curve list,
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// however, it costs in allocated space and vertex copies.
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TrimVertex *newjunk = trimvertexpool.get(maxvertex -i+1 /*-j*/);
222
for(k=0; k<maxvertex-i; k++)
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newjunk[k+1] = v[i+k];
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newjunk[k+1].nuid = jarc->nuid;
228
TrimVertex *vcopy = trimvertexpool.get(maxvertex);
229
for(k=0; k<maxvertex; k++)
231
vcopy[k].param[0] = v[k].param[0];
232
vcopy[k].param[1] = v[k].param[1];
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jarc->pwlArc->pts=vcopy;
236
v[i].nuid = jarc->nuid;
237
v[j].nuid = jarc->nuid;
238
vert_interp( &newjunk[0], &v[loc[0]], &v[loc[2]], param, value );
240
if( showingDegenerate() )
241
backend.triangle( &v[i], &newjunk[0], &v[j] );
243
vcopy[j+1].param[0]=newjunk[0].param[0];
244
vcopy[j+1].param[1]=newjunk[0].param[1];
247
jarc1 = new(arcpool) Arc( jarc,
248
new(pwlarcpool) PwlArc(maxvertex-i+1 , newjunk ) );
250
jarc->pwlArc->npts = j+2;
251
jarc1->next = jarc->next;
252
jarc1->next->prev = jarc1;
255
assert(jarc->check() != 0);
259
// JEB: This is the original version:
262
TrimVertex *newjunk = trimvertexpool.get(3);
263
v[i].nuid = jarc->nuid;
264
v[j].nuid = jarc->nuid;
267
vert_interp( &newjunk[1], &v[loc[0]], &v[loc[2]], param, value );
269
if( showingDegenerate() )
270
backend.triangle( &newjunk[2], &newjunk[1], &newjunk[0] );
272
// New vertex adjacent to both endpoints
273
if (maxvertex == 2) {
274
jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
275
jarc->pwlArc->npts = 2;
276
jarc->pwlArc->pts = newjunk;
277
jarc1->next = jarc->next;
278
jarc1->next->prev = jarc1;
281
assert(jarc->check() != 0);
285
// New vertex adjacent to ending point of arc
286
} else if (maxvertex - j == 2) {
287
jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
288
jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
289
jarc->pwlArc->npts = maxvertex-1;
290
jarc2->next = jarc->next;
291
jarc2->next->prev = jarc2;
296
assert(jarc->check() != 0);
299
// New vertex adjacent to starting point of arc
301
jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
302
jarc2 = new(arcpool) Arc( jarc,
303
new(pwlarcpool) PwlArc( maxvertex-1, &jarc->pwlArc->pts[1] ) );
304
jarc->pwlArc->npts = 2;
305
jarc->pwlArc->pts = newjunk;
306
jarc2->next = jarc->next;
307
jarc2->next->prev = jarc2;
312
assert(jarc->check() != 0);
315
// It's somewhere in the middle
317
jarc1 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk ) );
318
jarc2 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( 2, newjunk+1 ) );
319
jarc3 = new(arcpool) Arc( jarc, new(pwlarcpool) PwlArc( maxvertex-i, v+i ) );
320
jarc->pwlArc->npts = j + 1;
321
jarc3->next = jarc->next;
322
jarc3->next->prev = jarc3;
329
assert(jarc->check() != 0);
335
return -1; //picked -1 since it's not used
339
/*----------------------------------------------------------------------------
340
* pwlarc_intersect - find intersection of pwlArc and isoparametric line
341
*----------------------------------------------------------------------------
352
assert( pwlArc->npts > 0 );
355
TrimVertex *v = pwlArc->pts;
357
int imax = pwlArc->npts - 1;
358
assert( value > v[imin].param[param] );
359
assert( value < v[imax].param[param] );
360
while( (imax - imin) > 1 ) {
361
int imid = (imax + imin)/2;
362
if( v[imid].param[param] > value )
364
else if( v[imid].param[param] < value )
368
return INTERSECT_VERTEX;
373
return INTERSECT_EDGE;
375
TrimVertex *v = pwlArc->pts;
377
int imin = pwlArc->npts - 1;
378
assert( value > v[imin].param[param] );
379
assert( value < v[imax].param[param] );
380
while( (imin - imax) > 1 ) {
381
int imid = (imax + imin)/2;
382
if( v[imid].param[param] > value )
384
else if( v[imid].param[param] < value )
388
return INTERSECT_VERTEX;
393
return INTERSECT_EDGE;
397
/*----------------------------------------------------------------------------
398
* arc_classify - determine which side of a line a jarc lies
399
*----------------------------------------------------------------------------
403
arc_classify( Arc_ptr jarc, int param, REAL value )
407
tdiff = jarc->tail()[0] - value;
408
hdiff = jarc->head()[0] - value;
410
tdiff = jarc->tail()[1] - value;
411
hdiff = jarc->head()[1] - value;
417
} else if( hdiff == 0.0 ) {
422
} else if( tdiff == 0.0 ) {
425
} else if( hdiff == 0.0 ) {
433
} else if( hdiff == 0.0 ) {
442
Subdivider::classify_tailonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
444
/* tail at left, head on line */
447
while( (j = bin.removearc()) != NULL ) {
448
assert( arc_classify( j, 0, val ) == 0x02 );
451
REAL diff = j->next->head()[0] - val;
454
} else if( diff < 0.0 ) {
455
if( ccwTurn_sl( j, j->next ) )
460
if( j->next->tail()[1] > j->next->head()[1] )
469
Subdivider::classify_tailonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
471
/* tail at left, head on line */
474
while( (j = bin.removearc()) != NULL ) {
475
assert( arc_classify( j, 1, val ) == 0x02 );
478
REAL diff = j->next->head()[1] - val;
481
} else if( diff < 0.0 ) {
482
if( ccwTurn_tl( j, j->next ) )
487
if (j->next->tail()[0] > j->next->head()[0] )
496
Subdivider::classify_headonleft_s( Bin& bin, Bin& in, Bin& out, REAL val )
498
/* tail on line, head at left */
501
while( (j = bin.removearc()) != NULL ) {
502
assert( arc_classify( j, 0, val ) == 0x20 );
506
REAL diff = j->prev->tail()[0] - val;
509
} else if( diff < 0.0 ) {
510
if( ccwTurn_sl( j->prev, j ) )
515
if( j->prev->tail()[1] > j->prev->head()[1] )
524
Subdivider::classify_headonleft_t( Bin& bin, Bin& in, Bin& out, REAL val )
526
/* tail on line, head at left */
529
while( (j = bin.removearc()) != NULL ) {
530
assert( arc_classify( j, 1, val ) == 0x20 );
533
REAL diff = j->prev->tail()[1] - val;
536
} else if( diff < 0.0 ) {
537
if( ccwTurn_tl( j->prev, j ) )
542
if( j->prev->tail()[0] > j->prev->head()[0] )
552
Subdivider::classify_tailonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
554
/* tail at right, head on line */
557
while( (j = bin.removearc()) != NULL ) {
558
assert( arc_classify( j, 0, val ) == 0x12);
562
REAL diff = j->next->head()[0] - val;
564
if( ccwTurn_sr( j, j->next ) )
568
} else if( diff < 0.0 ) {
571
if( j->next->tail()[1] > j->next->head()[1] )
580
Subdivider::classify_tailonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
582
/* tail at right, head on line */
585
while( (j = bin.removearc()) != NULL ) {
586
assert( arc_classify( j, 1, val ) == 0x12);
590
REAL diff = j->next->head()[1] - val;
592
if( ccwTurn_tr( j, j->next ) )
596
} else if( diff < 0.0 ) {
599
if( j->next->tail()[0] > j->next->head()[0] )
608
Subdivider::classify_headonright_s( Bin& bin, Bin& in, Bin& out, REAL val )
610
/* tail on line, head at right */
613
while( (j = bin.removearc()) != NULL ) {
614
assert( arc_classify( j, 0, val ) == 0x21 );
618
REAL diff = j->prev->tail()[0] - val;
620
if( ccwTurn_sr( j->prev, j ) )
624
} else if( diff < 0.0 ) {
627
if( j->prev->tail()[1] > j->prev->head()[1] )
636
Subdivider::classify_headonright_t( Bin& bin, Bin& in, Bin& out, REAL val )
638
/* tail on line, head at right */
641
while( (j = bin.removearc()) != NULL ) {
642
assert( arc_classify( j, 1, val ) == 0x21 );
646
REAL diff = j->prev->tail()[1] - val;
648
if( ccwTurn_tr( j->prev, j ) )
652
} else if( diff < 0.0 ) {
655
if( j->prev->tail()[0] > j->prev->head()[0] )