Synchronize with trunk's revision r57629.
[reactos.git] / dll / opengl / glu32 / src / libnurbs / internals / knotvector.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 * knotvector.c++
37 *
38 */
39
40 #include "glimports.h"
41 #include "mystdio.h"
42 #include "myassert.h"
43 #include "knotvector.h"
44 #include "defines.h"
45
46 #ifdef __WATCOMC__
47 #pragma warning 726 10
48 #endif
49
50 void Knotvector::init( long _knotcount, long _stride, long _order, INREAL *_knotlist )
51 {
52 knotcount = _knotcount;
53 stride = _stride;
54 order = _order;
55 knotlist = new Knot[_knotcount];
56 assert( knotlist != 0 );
57
58 for( int i = 0; i != _knotcount; i++ )
59 knotlist[i] = (Knot) _knotlist[i];
60 }
61
62 Knotvector::Knotvector( void )
63 {
64 knotcount = 0;
65 stride = 0;
66 order = 0;
67 knotlist = 0;
68 }
69
70 Knotvector::~Knotvector( void )
71 {
72 if( knotlist ) delete[] knotlist;
73 }
74
75 int Knotvector::validate( void )
76 {
77 /* kindex is used as an array index so subtract one first,
78 * this propagates throughout the code so study carefully */
79 long kindex = knotcount-1;
80
81 if( order < 1 || order > MAXORDER ) {
82 // spline order un-supported
83 return( 1 );
84 }
85
86 if( knotcount < (2 * order) ) {
87 // too few knots
88 return( 2 );
89 }
90
91 if( identical( knotlist[kindex-(order-1)], knotlist[order-1]) ) {
92 // valid knot range is empty
93 return( 3 );
94 }
95
96 for( long i = 0; i < kindex; i++)
97 if( knotlist[i] > knotlist[i+1] ) {
98 // decreasing knot sequence
99 return( 4 );
100 }
101
102 /* check for valid multiplicity */
103
104 /* kindex is currently the index of the last knot.
105 * In the next loop it is decremented to ignore the last knot
106 * and the loop stops when kindex is 2 so as to ignore the first
107 * knot as well. These knots are not used in computing
108 * knot multiplicities.
109 */
110
111 long multi = 1;
112 for( ; kindex >= 1; kindex-- ) {
113 if( knotlist[kindex] - knotlist[kindex-1] < TOLERANCE ) {
114 multi++;
115 continue;
116 }
117 if ( multi > order ) {
118 // knot multiplicity greater than order of spline
119 return( 5 );
120 }
121 multi = 1;
122 }
123
124 if ( multi > order ) {
125 // knot multiplicity greater than order of spline
126 return( 5 );
127 }
128
129 return 0;
130 }
131
132 void Knotvector::show( const char *msg )
133 {
134 #ifndef NDEBUG
135 _glu_dprintf( "%s\n", msg );
136 _glu_dprintf( "order = %ld, count = %ld\n", order, knotcount );
137
138 for( int i=0; i<knotcount; i++ )
139 _glu_dprintf( "knot[%d] = %g\n", i, knotlist[i] );
140 #endif
141 }
142