1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/* Test GL_EXT_stencil_wrap extension.
* This is by no means complete, just a quick check.
*
* Brian Paul 30 October 2002
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
static void RunTest(void)
{
const GLenum prim = GL_LINES;
GLubyte val;
int bits, max, i;
GLboolean failed;
glGetIntegerv(GL_STENCIL_BITS, &bits);
max = (1 << bits) - 1;
glClearStencil(0);
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_ALWAYS, 0, ~0);
/* test GL_INCR (saturation) */
glClear(GL_STENCIL_BUFFER_BIT);
glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
failed = GL_FALSE;
printf("Testing GL_INCR...\n");
for (i = 1; i < max+10; i++) {
int expected = (i > max) ? max : i;
glBegin(prim);
glVertex2f(0.5, 0.5); glVertex2f(9.5, 0.5);
glEnd();
glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
if (val != expected) {
printf( "Failed GL_INCR test on iteration #%u "
"(got %u, expected %u)\n", i, val, expected );
failed = GL_TRUE;
}
}
if ( !failed ) printf("OK!\n");
/* test GL_INCR_WRAP_EXT (wrap around) */
glClear(GL_STENCIL_BUFFER_BIT);
glStencilOp(GL_KEEP, GL_KEEP, GL_INCR_WRAP_EXT);
failed = GL_FALSE;
printf("Testing GL_INCR_WRAP_EXT...\n");
for (i = 1; i < max+10; i++) {
int expected = i % (max + 1);
glBegin(prim);
glVertex2f(0.5, 0.5); glVertex2f(9.5, 0.5);
glEnd();
glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
if (val != expected) {
printf( "Failed GL_INCR_WRAP test on iteration #%u "
"(got %u, expected %u)\n", i, val, expected );
failed = GL_TRUE;
}
}
if ( !failed ) printf("OK!\n");
glClearStencil(max);
/* test GL_INCR (saturation) */
glClear(GL_STENCIL_BUFFER_BIT);
glStencilOp(GL_KEEP, GL_KEEP, GL_DECR);
failed = GL_FALSE;
printf("Testing GL_DECR...\n");
for (i = max-1; i > -10; i--) {
int expected = (i < 0) ? 0 : i;
glBegin(prim);
glVertex2f(0.5, 0.5); glVertex2f(9.5, 0.5);
glEnd();
glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
if (val != expected) {
printf( "Failed GL_DECR test on iteration #%u "
"(got %u, expected %u)\n", max - i, val, expected );
failed = GL_TRUE;
}
}
if ( !failed ) printf("OK!\n");
/* test GL_INCR_WRAP_EXT (wrap-around) */
glClear(GL_STENCIL_BUFFER_BIT);
glStencilOp(GL_KEEP, GL_KEEP, GL_DECR_WRAP_EXT);
failed = GL_FALSE;
printf("Testing GL_DECR_WRAP_EXT...\n");
for (i = max-1; i > -10; i--) {
int expected = (i < 0) ? max + i + 1: i;
glBegin(prim);
glVertex2f(0.5, 0.5); glVertex2f(9.5, 0.5);
glEnd();
glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
if (val != expected) {
printf( "Failed GL_DECR_WRAP test on iteration #%u "
"(got %u, expected %u)\n", max - i, val, expected );
failed = GL_TRUE;
}
}
if ( !failed ) printf("OK!\n");
glDisable(GL_STENCIL_TEST);
}
static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
RunTest();
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho(0, width, 0, height, -1, 1);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void Init( void )
{
const char * ver_str;
float version;
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
/* Check for both the extension string and GL version 1.4 on the
* outside chance that some silly vendor exports version 1.4 but doesn't
* export the extension string. The stencil-wrap modes are a required
* part of GL 1.4.
*/
ver_str = glGetString( GL_VERSION );
version = (ver_str == NULL) ? 1.0 : strtof( ver_str, NULL );
if ( !glutExtensionSupported("GL_EXT_stencil_wrap")
&& (version < 1.4) ) {
printf("Sorry, GL_EXT_stencil_wrap not supported.\n");
exit(1);
}
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 400, 400 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_STENCIL );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Display );
Init();
glutMainLoop();
return 0;
}
|
