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