progs/demos/paltex.c

   1 /* $Id: paltex.c,v 1.5 2000/10/04 18:15:39 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 static GLboolean Anim = 1;
  17
  18
  19 static void Idle( void )
  20 {
  21    float t = glutGet(GLUT_ELAPSED_TIME) * 0.001;  /* in seconds */
  22    Rot = t * 360 / 4;  /* 1 rotation per 4 seconds */
  23    glutPostRedisplay();
  24 }
  25
  26
  27 static void Display( void )
  28 {
  29    /* draw background gradient */
  30    glDisable(GL_TEXTURE_2D);
  31    glBegin(GL_POLYGON);
  32    glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
  33    glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
  34    glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5,  1.0);
  35    glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5,  1.0);
  36    glEnd();
  37
  38    glPushMatrix();
  39    glRotatef(Rot, 0, 0, 1);
  40
  41    glEnable(GL_TEXTURE_2D);
  42    glBegin(GL_POLYGON);
  43    glTexCoord2f(0, 1);  glVertex2f(-1, -0.5);
  44    glTexCoord2f(1, 1);  glVertex2f( 1, -0.5);
  45    glTexCoord2f(1, 0);  glVertex2f( 1,  0.5);
  46    glTexCoord2f(0, 0);  glVertex2f(-1,  0.5);
  47    glEnd();
  48
  49    glPopMatrix();
  50
  51    glutSwapBuffers();
  52 }
  53
  54
  55 static void Reshape( int width, int height )
  56 {
  57    glViewport( 0, 0, width, height );
  58    glMatrixMode( GL_PROJECTION );
  59    glLoadIdentity();
  60    glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
  61    glMatrixMode( GL_MODELVIEW );
  62    glLoadIdentity();
  63 }
  64
  65
  66 static void Key( unsigned char key, int x, int y )
  67 {
  68    (void) x;
  69    (void) y;
  70    switch (key) {
  71       case 27:
  72          exit(0);
  73          break;
  74       case 's':
  75          Rot += 0.5;
  76          break;
  77       case ' ':
  78          Anim = !Anim;
  79          if (Anim)
  80             glutIdleFunc( Idle );
  81          else
  82             glutIdleFunc( NULL );
  83          break;
  84    }
  85    glutPostRedisplay();
  86 }
  87
  88
  89 static void Init( void )
  90 {
  91 #define HEIGHT 8
  92 #define WIDTH 32
  93    static char texture[HEIGHT][WIDTH] = {
  94          "                                ",
  95          "    MMM    EEEE   SSS    AAA    ",
  96          "   M M M  E      S   S  A   A   ",
  97          "   M M M  EEEE    SS    A   A   ",
  98          "   M M M  E         SS  AAAAA   ",
  99          "   M   M  E      S   S  A   A   ",
 100          "   M   M   EEEE   SSS   A   A   ",
 101          "                                "
 102       };
 103    GLubyte table[256][4];
 104
 105    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 106       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 107       exit(0);
 108    }
 109
 110    /* load the color table for each texel-index */
 111    memset(table, 0, 256*4);
 112    table[' '][0] = 255;
 113    table[' '][1] = 255;
 114    table[' '][2] = 255;
 115    table[' '][3] = 64;
 116    table['M'][0] = 255;
 117    table['M'][1] = 0;
 118    table['M'][2] = 0;
 119    table['M'][3] = 255;
 120    table['E'][0] = 0;
 121    table['E'][1] = 255;
 122    table['E'][2] = 0;
 123    table['E'][3] = 255;
 124    table['S'][0] = 0;
 125    table['S'][1] = 0;
 126    table['S'][2] = 255;
 127    table['S'][3] = 255;
 128    table['A'][0] = 255;
 129    table['A'][1] = 255;
 130    table['A'][2] = 0;
 131    table['A'][3] = 255;
 132
 133 #ifdef GL_EXT_paletted_texture
 134
 135 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 136    printf("Using shared palette\n");
 137    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 138                    GL_RGBA,          /* internal format */
 139                    256,              /* table size */
 140                    GL_RGBA,          /* table format */
 141                    GL_UNSIGNED_BYTE, /* table type */
 142                    table);           /* the color table */
 143    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 144 #else
 145    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 146                    GL_RGBA,          /* internal format */
 147                    256,              /* table size */
 148                    GL_RGBA,          /* table format */
 149                    GL_UNSIGNED_BYTE, /* table type */
 150                    table);           /* the color table */
 151 #endif
 152
 153    glTexImage2D(GL_TEXTURE_2D,       /* target */
 154                 0,                   /* level */
 155                 GL_COLOR_INDEX8_EXT, /* internal format */
 156                 WIDTH, HEIGHT,       /* width, height */
 157                 0,                   /* border */
 158                 GL_COLOR_INDEX,      /* texture format */
 159                 GL_UNSIGNED_BYTE,    /* texture type */
 160                 texture);            /* teh texture */
 161 #endif
 162
 163    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 164    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 165    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 166    glEnable(GL_TEXTURE_2D);
 167
 168    glEnable(GL_BLEND);
 169    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 170 #undef HEIGHT 32
 171 #undef WIDTH 256
 172 }
 173
 174
 175
 176 /*
 177  * Color ramp test
 178  */
 179 static void Init2( void )
 180 {
 181 #define HEIGHT 32
 182 #define WIDTH 256
 183    static char texture[HEIGHT][WIDTH];
 184    GLubyte table[256][4];
 185    int i, j;
 186
 187    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 188       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 189       exit(0);
 190    }
 191
 192    for (j = 0; j < HEIGHT; j++) {
 193       for (i = 0; i < WIDTH; i++) {
 194          texture[j][i] = i;
 195       }
 196    }
 197
 198    for (i = 0; i < 255; i++) {
 199       table[i][0] = i;
 200       table[i][1] = 0;
 201       table[i][2] = 0;
 202       table[i][3] = 255;
 203    }
 204
 205 #ifdef GL_EXT_paletted_texture
 206
 207 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 208    printf("Using shared palette\n");
 209    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 210                    GL_RGBA,          /* internal format */
 211                    256,              /* table size */
 212                    GL_RGBA,          /* table format */
 213                    GL_UNSIGNED_BYTE, /* table type */
 214                    table);           /* the color table */
 215    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 216 #else
 217    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 218                    GL_RGBA,          /* internal format */
 219                    256,              /* table size */
 220                    GL_RGBA,          /* table format */
 221                    GL_UNSIGNED_BYTE, /* table type */
 222                    table);           /* the color table */
 223 #endif
 224
 225    glTexImage2D(GL_TEXTURE_2D,       /* target */
 226                 0,                   /* level */
 227                 GL_COLOR_INDEX8_EXT, /* internal format */
 228                 WIDTH, HEIGHT,       /* width, height */
 229                 0,                   /* border */
 230                 GL_COLOR_INDEX,      /* texture format */
 231                 GL_UNSIGNED_BYTE,    /* texture type */
 232                 texture);            /* teh texture */
 233 #endif
 234
 235    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 236    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 237    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 238    glEnable(GL_TEXTURE_2D);
 239
 240    glEnable(GL_BLEND);
 241    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 242 }
 243
 244
 245 int main( int argc, char *argv[] )
 246 {
 247    glutInit( &argc, argv );
 248    glutInitWindowPosition( 0, 0 );
 249    glutInitWindowSize( 400, 300 );
 250
 251    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 252
 253    glutCreateWindow(argv[0]);
 254
 255    Init();
 256
 257    glutReshapeFunc( Reshape );
 258    glutKeyboardFunc( Key );
 259    glutDisplayFunc( Display );
 260    if (Anim)
 261       glutIdleFunc( Idle );
 262
 263    glutMainLoop();
 264    return 0;
 265 }