src/demos/paltex.c

   1
   2 /*
   3  * Paletted texture demo.  Written by Brian Paul.
   4  * This program is in the public domain.
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <math.h>
  10 #include <string.h>
  11 #ifdef _WIN32
  12 #include <windows.h>
  13 #endif
  14 #include <GL/glew.h>
  15 #include "glut_wrap.h"
  16
  17
  18 static float Rot = 0.0;
  19 static GLboolean Anim = 1;
  20
  21
  22 static void Idle( void )
  23 {
  24    float t = glutGet(GLUT_ELAPSED_TIME) * 0.001;  /* in seconds */
  25    Rot = t * 360 / 4;  /* 1 rotation per 4 seconds */
  26    glutPostRedisplay();
  27 }
  28
  29
  30 static void Display( void )
  31 {
  32    /* draw background gradient */
  33    glDisable(GL_TEXTURE_2D);
  34    glBegin(GL_POLYGON);
  35    glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
  36    glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
  37    glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5,  1.0);
  38    glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5,  1.0);
  39    glEnd();
  40
  41    glPushMatrix();
  42    glRotatef(Rot, 0, 0, 1);
  43
  44    glEnable(GL_TEXTURE_2D);
  45    glBegin(GL_POLYGON);
  46    glTexCoord2f(0, 1);  glVertex2f(-1, -0.5);
  47    glTexCoord2f(1, 1);  glVertex2f( 1, -0.5);
  48    glTexCoord2f(1, 0);  glVertex2f( 1,  0.5);
  49    glTexCoord2f(0, 0);  glVertex2f(-1,  0.5);
  50    glEnd();
  51
  52    glPopMatrix();
  53
  54    glutSwapBuffers();
  55 }
  56
  57
  58 static void Reshape( int width, int height )
  59 {
  60    glViewport( 0, 0, width, height );
  61    glMatrixMode( GL_PROJECTION );
  62    glLoadIdentity();
  63    glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
  64    glMatrixMode( GL_MODELVIEW );
  65    glLoadIdentity();
  66 }
  67
  68
  69 static void Key( unsigned char key, int x, int y )
  70 {
  71    (void) x;
  72    (void) y;
  73    switch (key) {
  74       case 27:
  75          exit(0);
  76          break;
  77       case 's':
  78          Rot += 0.5;
  79          break;
  80       case ' ':
  81          Anim = !Anim;
  82          if (Anim)
  83             glutIdleFunc( Idle );
  84          else
  85             glutIdleFunc( NULL );
  86          break;
  87    }
  88    glutPostRedisplay();
  89 }
  90
  91
  92 static void Init( void )
  93 {
  94 #define HEIGHT 8
  95 #define WIDTH 32
  96    /* 257 = HEIGHT * WIDTH + 1 (for trailing '\0') */
  97    static char texture[257] = {"\
  98                                 \
  99     MMM    EEEE   SSS    AAA    \
 100    M M M  E      S   S  A   A   \
 101    M M M  EEEE    SS    A   A   \
 102    M M M  E         SS  AAAAA   \
 103    M   M  E      S   S  A   A   \
 104    M   M   EEEE   SSS   A   A   \
 105                                 "
 106       };
 107    GLubyte table[256][4];
 108
 109    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 110       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 111       exit(0);
 112    }
 113
 114    /* load the color table for each texel-index */
 115    memset(table, 0, 256*4);
 116    table[' '][0] = 255;
 117    table[' '][1] = 255;
 118    table[' '][2] = 255;
 119    table[' '][3] = 64;
 120    table['M'][0] = 255;
 121    table['M'][1] = 0;
 122    table['M'][2] = 0;
 123    table['M'][3] = 255;
 124    table['E'][0] = 0;
 125    table['E'][1] = 255;
 126    table['E'][2] = 0;
 127    table['E'][3] = 255;
 128    table['S'][0] = 0;
 129    table['S'][1] = 0;
 130    table['S'][2] = 255;
 131    table['S'][3] = 255;
 132    table['A'][0] = 255;
 133    table['A'][1] = 255;
 134    table['A'][2] = 0;
 135    table['A'][3] = 255;
 136
 137 #ifdef GL_EXT_paletted_texture
 138
 139 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 140    printf("Using shared palette\n");
 141    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 142                    GL_RGBA,          /* internal format */
 143                    256,              /* table size */
 144                    GL_RGBA,          /* table format */
 145                    GL_UNSIGNED_BYTE, /* table type */
 146                    table);           /* the color table */
 147    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 148 #else
 149    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 150                    GL_RGBA,          /* internal format */
 151                    256,              /* table size */
 152                    GL_RGBA,          /* table format */
 153                    GL_UNSIGNED_BYTE, /* table type */
 154                    table);           /* the color table */
 155 #endif
 156
 157    glTexImage2D(GL_TEXTURE_2D,       /* target */
 158                 0,                   /* level */
 159                 GL_COLOR_INDEX8_EXT, /* internal format */
 160                 WIDTH, HEIGHT,       /* width, height */
 161                 0,                   /* border */
 162                 GL_COLOR_INDEX,      /* texture format */
 163                 GL_UNSIGNED_BYTE,    /* texture type */
 164                 texture);            /* the texture */
 165 #endif
 166
 167    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 168    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 169    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 170    glEnable(GL_TEXTURE_2D);
 171
 172    glEnable(GL_BLEND);
 173    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 174 #undef HEIGHT
 175 #undef WIDTH
 176 }
 177
 178
 179
 180 /*
 181  * Color ramp test
 182  */
 183 static void Init2( void )
 184 {
 185 #define HEIGHT 32
 186 #define WIDTH 256
 187    static char texture[HEIGHT][WIDTH];
 188    GLubyte table[256][4];
 189    int i, j;
 190
 191    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 192       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 193       exit(0);
 194    }
 195
 196    for (j = 0; j < HEIGHT; j++) {
 197       for (i = 0; i < WIDTH; i++) {
 198          texture[j][i] = i;
 199       }
 200    }
 201
 202    for (i = 0; i < 255; i++) {
 203       table[i][0] = i;
 204       table[i][1] = 0;
 205       table[i][2] = 0;
 206       table[i][3] = 255;
 207    }
 208
 209 #ifdef GL_EXT_paletted_texture
 210
 211 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 212    printf("Using shared palette\n");
 213    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 214                    GL_RGBA,          /* internal format */
 215                    256,              /* table size */
 216                    GL_RGBA,          /* table format */
 217                    GL_UNSIGNED_BYTE, /* table type */
 218                    table);           /* the color table */
 219    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 220 #else
 221    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 222                    GL_RGBA,          /* internal format */
 223                    256,              /* table size */
 224                    GL_RGBA,          /* table format */
 225                    GL_UNSIGNED_BYTE, /* table type */
 226                    table);           /* the color table */
 227 #endif
 228
 229    glTexImage2D(GL_TEXTURE_2D,       /* target */
 230                 0,                   /* level */
 231                 GL_COLOR_INDEX8_EXT, /* internal format */
 232                 WIDTH, HEIGHT,       /* width, height */
 233                 0,                   /* border */
 234                 GL_COLOR_INDEX,      /* texture format */
 235                 GL_UNSIGNED_BYTE,    /* texture type */
 236                 texture);            /* teh texture */
 237 #endif
 238
 239    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 240    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 241    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 242    glEnable(GL_TEXTURE_2D);
 243
 244    glEnable(GL_BLEND);
 245    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 246 }
 247
 248
 249 int main( int argc, char *argv[] )
 250 {
 251    glutInitWindowSize( 400, 300 );
 252    glutInit( &argc, argv );
 253    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 254    glutCreateWindow(argv[0]);
 255    glewInit();
 256
 257    Init();
 258    (void) Init2; /* silence warning */
 259
 260    glutReshapeFunc( Reshape );
 261    glutKeyboardFunc( Key );
 262    glutDisplayFunc( Display );
 263    if (Anim)
 264       glutIdleFunc( Idle );
 265
 266    glutMainLoop();
 267    return 0;
 268 }