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
sgn(REAL x)48 inline long sgn( REAL x )
49 {
50 return (x < -TINY) ? -1 : ((x > TINY) ? 1 : 0 );
51 }
52
53
Varray(void)54 Varray::Varray( void )
55 {
56 int i;
57
58 varray = 0;
59 size = 0;
60 numquads = 0;
61
62 for (i = 0; i < 1000; i++) {
63 vval[i] = 0;
64 voffset[i] = 0;
65 }
66 }
67
~Varray(void)68 Varray::~Varray( void )
69 {
70 if( varray ) delete[] varray;
71 }
72
73 inline void
update(Arc_ptr arc,long dir[2],REAL val)74 Varray::update( Arc_ptr arc, long dir[2], REAL val )
75 {
76 register long ds = sgn(arc->tail()[0] - arc->prev->tail()[0]);
77 register long dt = sgn(arc->tail()[1] - arc->prev->tail()[1]);
78
79 if( dir[0] != ds || dir[1] != dt ) {
80 dir[0] = ds;
81 dir[1] = dt;
82 append( val );
83 }
84 }
85
86 void
grow(long guess)87 Varray::grow( long guess )
88 {
89 if( size < guess ) {
90 size = guess * 2;
91 if( varray ) delete[] varray;
92 varray = new REAL[size];
93 assert( varray != 0 );
94 }
95 }
96
97 long
init(REAL delta,Arc_ptr toparc,Arc_ptr botarc)98 Varray::init( REAL delta, Arc_ptr toparc, Arc_ptr botarc )
99 {
100 Arc_ptr left = toparc->next;
101 Arc_ptr right = toparc;
102 long ldir[2], rdir[2];
103
104 ldir[0] = sgn( left->tail()[0] - left->prev->tail()[0] );
105 ldir[1] = sgn( left->tail()[1] - left->prev->tail()[1] );
106 rdir[0] = sgn( right->tail()[0] - right->prev->tail()[0] );
107 rdir[1] = sgn( right->tail()[1] - right->prev->tail()[1] );
108
109 vval[0] = toparc->tail()[1];
110 numquads = 0;
111
112 while( 1 ) {
113 switch( sgn( left->tail()[1] - right->prev->tail()[1] ) ) {
114 case 1:
115 left = left->next;
116 update( left, ldir, left->prev->tail()[1] );
117 break;
118 case -1:
119 right = right->prev;
120 update( right, rdir, right->tail()[1] );
121 break;
122 case 0:
123 if( glu_abs(left->tail()[1] - botarc->tail()[1]) < TINY) goto end;
124 if( glu_abs(left->tail()[0]-right->prev->tail()[0]) < TINY &&
125 glu_abs(left->tail()[1]-right->prev->tail()[1]) < TINY) goto end;
126 left = left->next;
127 break;
128 }
129 }
130
131 end:
132 append( botarc->tail()[1] );
133
134 grow( ((long) ((vval[0] - vval[numquads])/delta)) + numquads + 2 );
135
136 long i, index = 0;
137 for( i=0; i<numquads; i++ ) {
138 voffset[i] = index;
139 varray[index++] = vval[i];
140 REAL dist = vval[i] - vval[i+1];
141 if( dist > delta ) {
142 long steps = ((long) (dist/delta)) +1;
143 float deltav = - dist / (REAL) steps;
144 for( long j=1; j<steps; j++ )
145 varray[index++] = vval[i] + j * deltav;
146 }
147 }
148 voffset[i] = index;
149 varray[index] = vval[i];
150 return index;
151 }
152
153