FreeWRL / FreeX3D 4.3.0
varray.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 * varray.c++
37 *
38 */
39
40#include "glimports.h"
41#include "myassert.h"
42#include "mystdio.h"
43#include "varray.h"
44#include "arc.h"
45#include "simplemath.h" // glu_abs()
46
47#define TINY 0.0001
48inline long sgn( REAL x )
49{
50 return (x < -TINY) ? -1 : ((x > TINY) ? 1 : 0 );
51}
52
53
54Varray::Varray( void )
55{
56 varray = 0;
57 size = 0;
58}
59
60Varray::~Varray( void )
61{
62 if( varray ) delete[] varray;
63}
64
65inline void
66Varray::update( Arc_ptr arc, long dir[2], REAL val )
67{
68 register long ds = sgn(arc->tail()[0] - arc->prev->tail()[0]);
69 register long dt = sgn(arc->tail()[1] - arc->prev->tail()[1]);
70
71 if( dir[0] != ds || dir[1] != dt ) {
72 dir[0] = ds;
73 dir[1] = dt;
74 append( val );
75 }
76}
77
78void
79Varray::grow( long guess )
80{
81 if( size < guess ) {
82 size = guess * 2;
83 if( varray ) delete[] varray;
84 varray = new REAL[size];
85 assert( varray != 0 );
86 }
87}
88
89long
90Varray::init( REAL delta, Arc_ptr toparc, Arc_ptr botarc )
91{
92 Arc_ptr left = toparc->next;
93 Arc_ptr right = toparc;
94 long ldir[2], rdir[2];
95
96 ldir[0] = sgn( left->tail()[0] - left->prev->tail()[0] );
97 ldir[1] = sgn( left->tail()[1] - left->prev->tail()[1] );
98 rdir[0] = sgn( right->tail()[0] - right->prev->tail()[0] );
99 rdir[1] = sgn( right->tail()[1] - right->prev->tail()[1] );
100
101 vval[0] = toparc->tail()[1];
102 numquads = 0;
103
104 while( 1 ) {
105 switch( sgn( left->tail()[1] - right->prev->tail()[1] ) ) {
106 case 1:
107 left = left->next;
108 update( left, ldir, left->prev->tail()[1] );
109 break;
110 case -1:
111 right = right->prev;
112 update( right, rdir, right->tail()[1] );
113 break;
114 case 0:
115 if( glu_abs(left->tail()[1] - botarc->tail()[1]) < TINY) goto end;
116 if( glu_abs(left->tail()[0]-right->prev->tail()[0]) < TINY &&
117 glu_abs(left->tail()[1]-right->prev->tail()[1]) < TINY) goto end;
118 left = left->next;
119 break;
120 }
121 }
122
123end:
124 append( botarc->tail()[1] );
125
126 grow( ((long) ((vval[0] - vval[numquads])/delta)) + numquads + 2 );
127
128 long i, index = 0;
129 for( i=0; i<numquads; i++ ) {
130 voffset[i] = index;
131 varray[index++] = vval[i];
132 REAL dist = vval[i] - vval[i+1];
133 if( dist > delta ) {
134 long steps = ((long) (dist/delta)) +1;
135 float deltav = - dist / (REAL) steps;
136 for( long j=1; j<steps; j++ )
137 varray[index++] = vval[i] + j * deltav;
138 }
139 }
140 voffset[i] = index;
141 varray[index] = vval[i];
142 return index;
143}
144