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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
|
/* $Id: paltex.c,v 1.7 2002/01/16 00:48:43 kschultz Exp $ */
/*
* Paletted texture demo. Written by Brian Paul.
* This program is in the public domain.
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#endif
#define GL_GLEXT_LEGACY
#include <GL/glut.h>
static float Rot = 0.0;
static GLboolean Anim = 1;
static void Idle( void )
{
float t = glutGet(GLUT_ELAPSED_TIME) * 0.001; /* in seconds */
Rot = t * 360 / 4; /* 1 rotation per 4 seconds */
glutPostRedisplay();
}
static void Display( void )
{
/* draw background gradient */
glDisable(GL_TEXTURE_2D);
glBegin(GL_POLYGON);
glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5, 1.0);
glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5, 1.0);
glEnd();
glPushMatrix();
glRotatef(Rot, 0, 0, 1);
glEnable(GL_TEXTURE_2D);
glBegin(GL_POLYGON);
glTexCoord2f(0, 1); glVertex2f(-1, -0.5);
glTexCoord2f(1, 1); glVertex2f( 1, -0.5);
glTexCoord2f(1, 0); glVertex2f( 1, 0.5);
glTexCoord2f(0, 0); glVertex2f(-1, 0.5);
glEnd();
glPopMatrix();
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
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;
case 's':
Rot += 0.5;
break;
case ' ':
Anim = !Anim;
if (Anim)
glutIdleFunc( Idle );
else
glutIdleFunc( NULL );
break;
}
glutPostRedisplay();
}
static void Init( void )
{
#define HEIGHT 8
#define WIDTH 32
static char texture[HEIGHT][WIDTH] = {
" ",
" MMM EEEE SSS AAA ",
" M M M E S S A A ",
" M M M EEEE SS A A ",
" M M M E SS AAAAA ",
" M M E S S A A ",
" M M EEEE SSS A A ",
" "
};
GLubyte table[256][4];
if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
printf("Sorry, GL_EXT_paletted_texture not supported\n");
exit(0);
}
/* load the color table for each texel-index */
memset(table, 0, 256*4);
table[' '][0] = 255;
table[' '][1] = 255;
table[' '][2] = 255;
table[' '][3] = 64;
table['M'][0] = 255;
table['M'][1] = 0;
table['M'][2] = 0;
table['M'][3] = 255;
table['E'][0] = 0;
table['E'][1] = 255;
table['E'][2] = 0;
table['E'][3] = 255;
table['S'][0] = 0;
table['S'][1] = 0;
table['S'][2] = 255;
table['S'][3] = 255;
table['A'][0] = 255;
table['A'][1] = 255;
table['A'][2] = 0;
table['A'][3] = 255;
#ifdef GL_EXT_paletted_texture
#if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
printf("Using shared palette\n");
glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */
glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
#else
glColorTableEXT(GL_TEXTURE_2D, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */
#endif
glTexImage2D(GL_TEXTURE_2D, /* target */
0, /* level */
GL_COLOR_INDEX8_EXT, /* internal format */
WIDTH, HEIGHT, /* width, height */
0, /* border */
GL_COLOR_INDEX, /* texture format */
GL_UNSIGNED_BYTE, /* texture type */
texture); /* teh texture */
#endif
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
#undef HEIGHT
#undef WIDTH
}
/*
* Color ramp test
*/
static void Init2( void )
{
#define HEIGHT 32
#define WIDTH 256
static char texture[HEIGHT][WIDTH];
GLubyte table[256][4];
int i, j;
if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
printf("Sorry, GL_EXT_paletted_texture not supported\n");
exit(0);
}
for (j = 0; j < HEIGHT; j++) {
for (i = 0; i < WIDTH; i++) {
texture[j][i] = i;
}
}
for (i = 0; i < 255; i++) {
table[i][0] = i;
table[i][1] = 0;
table[i][2] = 0;
table[i][3] = 255;
}
#ifdef GL_EXT_paletted_texture
#if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
printf("Using shared palette\n");
glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */
glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
#else
glColorTableEXT(GL_TEXTURE_2D, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */
#endif
glTexImage2D(GL_TEXTURE_2D, /* target */
0, /* level */
GL_COLOR_INDEX8_EXT, /* internal format */
WIDTH, HEIGHT, /* width, height */
0, /* border */
GL_COLOR_INDEX, /* texture format */
GL_UNSIGNED_BYTE, /* texture type */
texture); /* teh texture */
#endif
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 400, 300 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
glutCreateWindow(argv[0]);
Init();
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Display );
if (Anim)
glutIdleFunc( Idle );
glutMainLoop();
return 0;
}
|
