Synchronize with trunk's revision r57629.
[reactos.git] / dll / opengl / glu32 / src / libnurbs / internals / hull.cc
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 * hull.c++
37 *
38 */
39
40 #include "glimports.h"
41 #include "myassert.h"
42 #include "mystdio.h"
43 #include "hull.h"
44 #include "gridvertex.h"
45 #include "gridtrimvertex.h"
46 #include "gridline.h"
47 #include "trimline.h"
48 #include "uarray.h"
49 #include "trimregion.h"
50
51 Hull::Hull( void )
52 {}
53
54 Hull::~Hull( void )
55 {}
56
57 /*----------------------------------------------------------------------
58 * Hull:init - this routine does the initialization needed before any
59 * calls to nextupper or nextlower can be made.
60 *----------------------------------------------------------------------
61 */
62 void
63 Hull::init( void )
64 {
65 TrimVertex *lfirst = left.first();
66 TrimVertex *llast = left.last();
67 if( lfirst->param[0] <= llast->param[0] ) {
68 fakeleft.init( left.first() );
69 upper.left = &fakeleft;
70 lower.left = &left;
71 } else {
72 fakeleft.init( left.last() );
73 lower.left = &fakeleft;
74 upper.left = &left;
75 }
76 upper.left->last();
77 lower.left->first();
78
79 if( top.ustart <= top.uend ) {
80 upper.line = &top;
81 upper.index = top.ustart;
82 } else
83 upper.line = 0;
84
85 if( bot.ustart <= bot.uend ) {
86 lower.line = &bot;
87 lower.index = bot.ustart;
88 } else
89 lower.line = 0;
90
91 TrimVertex *rfirst = right.first();
92 TrimVertex *rlast = right.last();
93 if( rfirst->param[0] <= rlast->param[0] ) {
94 fakeright.init( right.last() );
95 lower.right = &fakeright;
96 upper.right = &right;
97 } else {
98 fakeright.init( right.first() );
99 upper.right = &fakeright;
100 lower.right = &right;
101 }
102 upper.right->first();
103 lower.right->last();
104 }
105
106 /*----------------------------------------------------------------------
107 * nextupper - find next vertex on upper hull of trim region.
108 * - if vertex is on trim curve, set vtop point to
109 * that vertex. if vertex is on grid, set vtop to
110 * point to temporary area and stuff coordinants into
111 * temporary vertex. Also, place grid coords in temporary
112 * grid vertex.
113 *----------------------------------------------------------------------
114 */
115 GridTrimVertex *
116 Hull::nextupper( GridTrimVertex *gv )
117 {
118 if( upper.left ) {
119 gv->set( upper.left->prev() );
120 if( gv->isTrimVert() ) return gv;
121 upper.left = 0;
122 }
123
124 if( upper.line ) {
125 assert( upper.index <= upper.line->uend );
126 gv->set( uarray.uarray[upper.index], upper.line->vval );
127 gv->set( upper.index, upper.line->vindex );
128 if( upper.index++ == upper.line->uend ) upper.line = 0;
129 return gv;
130 }
131
132 if( upper.right ) {
133 gv->set( upper.right->next() );
134 if( gv->isTrimVert() ) return gv;
135 upper.right = 0;
136 }
137
138 return 0;
139 }
140
141 GridTrimVertex *
142 Hull::nextlower( register GridTrimVertex *gv )
143 {
144 if( lower.left ) {
145 gv->set( lower.left->next() );
146 if( gv->isTrimVert() ) return gv;
147 lower.left = 0;
148 }
149
150 if( lower.line ) {
151 gv->set( uarray.uarray[lower.index], lower.line->vval );
152 gv->set( lower.index, lower.line->vindex );
153 if( lower.index++ == lower.line->uend ) lower.line = 0;
154 return gv;
155 }
156
157 if( lower.right ) {
158 gv->set( lower.right->prev() );
159 if( gv->isTrimVert() ) return gv;
160 lower.right = 0;
161 }
162
163 return 0;
164 }
165