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/* $Id: paltex.c,v 1.9 2002/07/22 13:45:31 brianp 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
/* 257 = HEIGHT * WIDTH + 1 (for trailing '\0') */
static char texture[257] = {"\
\
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); /* the 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;
}
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