progs/demos/paltex.c

   1 /* $Id: paltex.c,v 1.4 2000/06/27 17:12:10 brianp Exp $ */
   2
   3 /*
   4  * Paletted texture demo.  Written by Brian Paul.
   5  * This program is in the public domain.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <math.h>
  11 #define GL_GLEXT_LEGACY
  12 #include <GL/glut.h>
  13
  14
  15 static float Rot = 0.0;
  16
  17
  18 static void Idle( void )
  19 {
  20    Rot += 5.0;
  21    glutPostRedisplay();
  22 }
  23
  24
  25 static void Display( void )
  26 {
  27    glClear( GL_COLOR_BUFFER_BIT );
  28
  29    glPushMatrix();
  30    glRotatef(Rot, 0, 0, 1);
  31
  32    glBegin(GL_POLYGON);
  33    glTexCoord2f(0, 1);  glVertex2f(-1, -0.5);
  34    glTexCoord2f(1, 1);  glVertex2f( 1, -0.5);
  35    glTexCoord2f(1, 0);  glVertex2f( 1,  0.5);
  36    glTexCoord2f(0, 0);  glVertex2f(-1,  0.5);
  37    glEnd();
  38
  39    glPopMatrix();
  40
  41    glutSwapBuffers();
  42 }
  43
  44
  45 static void Reshape( int width, int height )
  46 {
  47    glViewport( 0, 0, width, height );
  48    glMatrixMode( GL_PROJECTION );
  49    glLoadIdentity();
  50    glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  51    glMatrixMode( GL_MODELVIEW );
  52    glLoadIdentity();
  53    glTranslatef( 0.0, 0.0, -7.0 );
  54 }
  55
  56
  57 static void Key( unsigned char key, int x, int y )
  58 {
  59    (void) x;
  60    (void) y;
  61    switch (key) {
  62       case 27:
  63          exit(0);
  64          break;
  65    }
  66    glutPostRedisplay();
  67 }
  68
  69
  70 static void Init( void )
  71 {
  72 #define HEIGHT 8
  73 #define WIDTH 32
  74    static char texture[HEIGHT][WIDTH] = {
  75          "                                ",
  76          "    MMM    EEEE   SSS    AAA    ",
  77          "   M M M  E      S   S  A   A   ",
  78          "   M M M  EEEE    SS    A   A   ",
  79          "   M M M  E         SS  AAAAA   ",
  80          "   M   M  E      S   S  A   A   ",
  81          "   M   M   EEEE   SSS   A   A   ",
  82          "                                "
  83       };
  84    GLubyte table[256][4];
  85
  86    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
  87       printf("Sorry, GL_EXT_paletted_texture not supported\n");
  88       exit(0);
  89    }
  90
  91    /* load the color table for each texel-index */
  92    table[' '][0] = 50;
  93    table[' '][1] = 50;
  94    table[' '][2] = 50;
  95    table[' '][3] = 50;
  96    table['M'][0] = 255;
  97    table['M'][1] = 0;
  98    table['M'][2] = 0;
  99    table['M'][3] = 0;
 100    table['E'][0] = 0;
 101    table['E'][1] = 255;
 102    table['E'][2] = 0;
 103    table['E'][3] = 0;
 104    table['S'][0] = 40;
 105    table['S'][1] = 40;
 106    table['S'][2] = 255;
 107    table['S'][3] = 0;
 108    table['A'][0] = 255;
 109    table['A'][1] = 255;
 110    table['A'][2] = 0;
 111    table['A'][3] = 0;
 112
 113 #ifdef GL_EXT_paletted_texture
 114
 115 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 116    printf("Using shared palette\n");
 117    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 118                    GL_RGBA,          /* internal format */
 119                    256,              /* table size */
 120                    GL_RGBA,          /* table format */
 121                    GL_UNSIGNED_BYTE, /* table type */
 122                    table);           /* the color table */
 123    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 124 #else
 125    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 126                    GL_RGBA,          /* internal format */
 127                    256,              /* table size */
 128                    GL_RGBA,          /* table format */
 129                    GL_UNSIGNED_BYTE, /* table type */
 130                    table);           /* the color table */
 131 #endif
 132
 133    glTexImage2D(GL_TEXTURE_2D,       /* target */
 134                 0,                   /* level */
 135                 GL_COLOR_INDEX8_EXT, /* internal format */
 136                 WIDTH, HEIGHT,       /* width, height */
 137                 0,                   /* border */
 138                 GL_COLOR_INDEX,      /* texture format */
 139                 GL_UNSIGNED_BYTE,    /* texture type */
 140                 texture);            /* teh texture */
 141 #endif
 142
 143    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 144    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 145    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 146    glEnable(GL_TEXTURE_2D);
 147 }
 148
 149
 150 int main( int argc, char *argv[] )
 151 {
 152    glutInit( &argc, argv );
 153    glutInitWindowPosition( 0, 0 );
 154    glutInitWindowSize( 400, 400 );
 155
 156    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 157
 158    glutCreateWindow(argv[0]);
 159
 160    Init();
 161
 162    glutReshapeFunc( Reshape );
 163    glutKeyboardFunc( Key );
 164    glutDisplayFunc( Display );
 165    glutIdleFunc( Idle );
 166
 167    glutMainLoop();
 168    return 0;
 169 }