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 
143