1/*
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:
9**
10** http://oss.sgi.com/projects/FreeB
11**
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.
17**
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.
23**
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
28** 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.
33*/
34
35/*
36 * splitarcs.c++
37 *
38 */
39
40#include "glimports.h"
41#include "myassert.h"
42#include "mysetjmp.h"
43#include "mystdio.h"
44#include "subdivider.h"
45#include "arcsorter.h"
46#include "arc.h"
47#include "bin.h"
48
49/* local preprocessor definitions */
50#define MAXARCS	10
51
52/*----------------------------------------------------------------------------
53 * Subdivider::split - split trim regions in source bin by line (param == value).
54 *----------------------------------------------------------------------------
55 */
56
57void
58Subdivider::split( Bin& bin, Bin& left, Bin& right, int param, REAL value )
59{
60    Bin	intersections, unknown;
61
62    partition( bin, left, intersections, right, unknown, param, value );
63
64    int	count = intersections.numarcs();
65    if( count % 2 ) {
66#ifndef NDEBUG
67	left.show( "left" );
68	intersections.show( "intersections" );
69	right.show( "right" );
70#endif
71	::mylongjmp( jumpbuffer, 29 );
72    }
73
74    Arc_ptr arclist[MAXARCS], *list;
75    if( count >= MAXARCS ) {
76	list = new Arc_ptr[count];
77    } else {
78	list = arclist;
79    }
80
81    Arc_ptr jarc, *last, *lptr;
82    for( last = list; (jarc=intersections.removearc()) != NULL; last++ )
83	*last = jarc;
84
85    if( param == 0 ) { /* sort into increasing t order */
86	ArcSdirSorter sorter(*this);
87	sorter.qsort( list, count );
88
89        //::qsort ((void *)list, count, sizeof(Arc_ptr), (cmpfunc)compare_s);
90	for( lptr=list; lptr<last; lptr+=2 )
91	    check_s ( lptr[0], lptr[1] );
92	for( lptr=list; lptr<last; lptr+=2 )
93	    join_s ( left, right, lptr[0], lptr[1] );
94	for( lptr=list; lptr != last; lptr++ ) {
95	    if( ((*lptr)->head()[0] <= value) && ((*lptr)->tail()[0] <= value) )
96		left.addarc( *lptr  );
97	    else
98		right.addarc( *lptr  );
99	}
100    } else { /* sort into decreasing s order */
101	ArcTdirSorter sorter(*this);
102	sorter.qsort( list, count );
103        //::qsort ((void *)list, count, sizeof(Arc_ptr), (cmpfunc)compare_t);
104	for( lptr=list; lptr<last; lptr+=2 )
105	    check_t ( lptr[0], lptr[1] );
106	for( lptr=list; lptr<last; lptr+=2 )
107	    join_t ( left, right, lptr[0], lptr[1] );
108	for( lptr=list; lptr != last; lptr++ ) {
109	    if( ((*lptr)->head()[1] <= value) && ((*lptr)->tail()[1] <= value) )
110		left.addarc( *lptr  );
111	    else
112		right.addarc( *lptr  );
113	}
114    }
115
116    if( list != arclist ) delete[] list;
117    unknown.adopt();
118}
119
120
121void
122Subdivider::check_s( Arc_ptr jarc1, Arc_ptr jarc2 )
123{
124    assert( jarc1->check( ) != 0 );
125    assert( jarc2->check( ) != 0 );
126    assert( jarc1->next->check( ) != 0 );
127    assert( jarc2->next->check( ) != 0 );
128    assert( jarc1 != jarc2 );
129
130    /* XXX - if these assertions fail, it is due to user error or
131	     undersampling */
132    if( ! ( jarc1->tail()[0] < (jarc1)->head()[0] ) ) {
133#ifndef NDEBUG
134	_glu_dprintf( "s difference %f\n",  (jarc1)->tail()[0] - (jarc1)->head()[0] );
135#endif
136	::mylongjmp( jumpbuffer, 28 );
137    }
138
139    if( ! ( jarc2->tail()[0] > (jarc2)->head()[0] ) ) {
140#ifndef NDEBUG
141	_glu_dprintf( "s difference %f\n",  (jarc2)->tail()[0] - (jarc2)->head()[0] );
142#endif
143	::mylongjmp( jumpbuffer, 28 );
144    }
145}
146
147inline void
148Subdivider::link( Arc_ptr jarc1, Arc_ptr jarc2, Arc_ptr up, Arc_ptr down )
149{
150    up->nuid = down->nuid = 0;		// XXX
151
152    up->next = jarc2;
153    down->next = jarc1;
154    up->prev = jarc1->prev;
155    down->prev = jarc2->prev;
156
157    down->next->prev = down;
158    up->next->prev = up;
159    down->prev->next = down;
160    up->prev->next = up;
161}
162
163inline void
164Subdivider::simple_link( Arc_ptr jarc1, Arc_ptr jarc2 )
165{
166    Arc_ptr tmp = jarc2->prev;
167    jarc2->prev = jarc1->prev;
168    jarc1->prev = tmp;
169    jarc2->prev->next = jarc2;
170    jarc1->prev->next = jarc1;
171}
172
173
174/*----------------------------------------------------------------------------
175 * join - add a pair of oppositely directed jordan arcs between two arcs
176 *----------------------------------------------------------------------------
177 */
178
179void
180Subdivider::join_s( Bin& left, Bin& right, Arc_ptr jarc1, Arc_ptr jarc2 )
181{
182    assert( jarc1->check( ) != 0);
183    assert( jarc2->check( ) != 0);
184    assert( jarc1 != jarc2 );
185
186    if( ! jarc1->getitail() )
187	jarc1 = jarc1->next;
188
189    if( ! jarc2->getitail() )
190	jarc2 = jarc2->next;
191
192    REAL s = jarc1->tail()[0];
193    REAL t1 = jarc1->tail()[1];
194    REAL t2 = jarc2->tail()[1];
195
196    if( t1 == t2 ) {
197	simple_link( jarc1, jarc2 );
198    } else {
199	Arc_ptr newright = new(arcpool) Arc( arc_right, 0 );
200	Arc_ptr newleft = new(arcpool) Arc( arc_left, 0 );
201	assert( t1 < t2 );
202	if( isBezierArcType() ) {
203	    arctessellator.bezier( newright, s, s, t1, t2 );
204	    arctessellator.bezier( newleft, s, s, t2, t1 );
205	} else {
206	    arctessellator.pwl_right( newright, s, t1, t2, stepsizes[0] );
207	    arctessellator.pwl_left( newleft, s, t2, t1, stepsizes[2] );
208	}
209	link( jarc1, jarc2, newright, newleft );
210	left.addarc( newright  );
211	right.addarc( newleft  );
212    }
213
214    assert( jarc1->check( ) != 0 );
215    assert( jarc2->check( ) != 0 );
216    assert( jarc1->next->check( ) != 0);
217    assert( jarc2->next->check( ) != 0);
218}
219
220void
221Subdivider::check_t( Arc_ptr jarc1, Arc_ptr jarc2 )
222{
223    assert( jarc1->check( ) != 0 );
224    assert( jarc2->check( ) != 0 );
225    assert( jarc1->next->check( ) != 0 );
226    assert( jarc2->next->check( ) != 0 );
227    assert( jarc1 != jarc2 );
228
229    /* XXX - if these assertions fail, it is due to user error or
230	     undersampling */
231    if( ! ( jarc1->tail()[1] < (jarc1)->head()[1] ) ) {
232#ifndef NDEBUG
233	_glu_dprintf( "t difference %f\n",  jarc1->tail()[1] - (jarc1)->head()[1] );
234#endif
235	::mylongjmp( jumpbuffer, 28 );
236    }
237
238    if( ! ( jarc2->tail()[1] > (jarc2)->head()[1] ) ) {
239#ifndef NDEBUG
240	_glu_dprintf( "t difference %f\n",  jarc2->tail()[1] - (jarc2)->head()[1] );
241#endif
242	::mylongjmp( jumpbuffer, 28 );
243    }
244}
245
246/*----------------------------------------------------------------------------
247 * join_t - add a pair of oppositely directed jordan arcs between two arcs
248 *----------------------------------------------------------------------------
249 */
250
251void
252Subdivider::join_t( Bin& bottom, Bin& top, Arc_ptr jarc1, Arc_ptr jarc2 )
253{
254    assert( jarc1->check( ) != 0 );
255    assert( jarc2->check( ) != 0 );
256    assert( jarc1->next->check( ) != 0 );
257    assert( jarc2->next->check( ) != 0 );
258    assert( jarc1 != jarc2 );
259
260    if( ! jarc1->getitail() )
261	jarc1 = jarc1->next;
262
263    if( ! jarc2->getitail() )
264	jarc2 = jarc2->next;
265
266    REAL s1 = jarc1->tail()[0];
267    REAL s2 = jarc2->tail()[0];
268    REAL t  = jarc1->tail()[1];
269
270    if( s1 == s2 ) {
271	simple_link( jarc1, jarc2 );
272    } else {
273	Arc_ptr newtop = new(arcpool) Arc( arc_top, 0 );
274	Arc_ptr newbot = new(arcpool) Arc( arc_bottom, 0 );
275	assert( s1 > s2 );
276	if( isBezierArcType() ) {
277	    arctessellator.bezier( newtop, s1, s2, t, t );
278	    arctessellator.bezier( newbot, s2, s1, t, t );
279	} else {
280	    arctessellator.pwl_top( newtop, t, s1, s2, stepsizes[1] );
281	    arctessellator.pwl_bottom( newbot, t, s2, s1, stepsizes[3] );
282	}
283	link( jarc1, jarc2, newtop, newbot );
284	bottom.addarc( newtop  );
285	top.addarc( newbot  );
286    }
287
288    assert( jarc1->check( ) != 0 );
289    assert( jarc2->check( ) != 0 );
290    assert( jarc1->next->check( ) != 0 );
291    assert( jarc2->next->check( ) != 0 );
292}
293
294