progs/demos/paltex.c

   1 /* $Id: paltex.c,v 1.9 2002/07/22 13:45:31 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 #include <string.h>
  12 #ifdef _WIN32
  13 #include <windows.h>
  14 #endif
  15 #define GL_GLEXT_LEGACY
  16 #include <GL/glut.h>
  17
  18
  19 static float Rot = 0.0;
  20 static GLboolean Anim = 1;
  21
  22
  23 static void Idle( void )
  24 {
  25    float t = glutGet(GLUT_ELAPSED_TIME) * 0.001;  /* in seconds */
  26    Rot = t * 360 / 4;  /* 1 rotation per 4 seconds */
  27    glutPostRedisplay();
  28 }
  29
  30
  31 static void Display( void )
  32 {
  33    /* draw background gradient */
  34    glDisable(GL_TEXTURE_2D);
  35    glBegin(GL_POLYGON);
  36    glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
  37    glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
  38    glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5,  1.0);
  39    glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5,  1.0);
  40    glEnd();
  41
  42    glPushMatrix();
  43    glRotatef(Rot, 0, 0, 1);
  44
  45    glEnable(GL_TEXTURE_2D);
  46    glBegin(GL_POLYGON);
  47    glTexCoord2f(0, 1);  glVertex2f(-1, -0.5);
  48    glTexCoord2f(1, 1);  glVertex2f( 1, -0.5);
  49    glTexCoord2f(1, 0);  glVertex2f( 1,  0.5);
  50    glTexCoord2f(0, 0);  glVertex2f(-1,  0.5);
  51    glEnd();
  52
  53    glPopMatrix();
  54
  55    glutSwapBuffers();
  56 }
  57
  58
  59 static void Reshape( int width, int height )
  60 {
  61    glViewport( 0, 0, width, height );
  62    glMatrixMode( GL_PROJECTION );
  63    glLoadIdentity();
  64    glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
  65    glMatrixMode( GL_MODELVIEW );
  66    glLoadIdentity();
  67 }
  68
  69
  70 static void Key( unsigned char key, int x, int y )
  71 {
  72    (void) x;
  73    (void) y;
  74    switch (key) {
  75       case 27:
  76          exit(0);
  77          break;
  78       case 's':
  79          Rot += 0.5;
  80          break;
  81       case ' ':
  82          Anim = !Anim;
  83          if (Anim)
  84             glutIdleFunc( Idle );
  85          else
  86             glutIdleFunc( NULL );
  87          break;
  88    }
  89    glutPostRedisplay();
  90 }
  91
  92
  93 static void Init( void )
  94 {
  95 #define HEIGHT 8
  96 #define WIDTH 32
  97    /* 257 = HEIGHT * WIDTH + 1 (for trailing '\0') */
  98    static char texture[257] = {"\
  99                                 \
 100     MMM    EEEE   SSS    AAA    \
 101    M M M  E      S   S  A   A   \
 102    M M M  EEEE    SS    A   A   \
 103    M M M  E         SS  AAAAA   \
 104    M   M  E      S   S  A   A   \
 105    M   M   EEEE   SSS   A   A   \
 106                                 "
 107       };
 108    GLubyte table[256][4];
 109
 110    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 111       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 112       exit(0);
 113    }
 114
 115    /* load the color table for each texel-index */
 116    memset(table, 0, 256*4);
 117    table[' '][0] = 255;
 118    table[' '][1] = 255;
 119    table[' '][2] = 255;
 120    table[' '][3] = 64;
 121    table['M'][0] = 255;
 122    table['M'][1] = 0;
 123    table['M'][2] = 0;
 124    table['M'][3] = 255;
 125    table['E'][0] = 0;
 126    table['E'][1] = 255;
 127    table['E'][2] = 0;
 128    table['E'][3] = 255;
 129    table['S'][0] = 0;
 130    table['S'][1] = 0;
 131    table['S'][2] = 255;
 132    table['S'][3] = 255;
 133    table['A'][0] = 255;
 134    table['A'][1] = 255;
 135    table['A'][2] = 0;
 136    table['A'][3] = 255;
 137
 138 #ifdef GL_EXT_paletted_texture
 139
 140 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 141    printf("Using shared palette\n");
 142    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 143                    GL_RGBA,          /* internal format */
 144                    256,              /* table size */
 145                    GL_RGBA,          /* table format */
 146                    GL_UNSIGNED_BYTE, /* table type */
 147                    table);           /* the color table */
 148    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 149 #else
 150    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 151                    GL_RGBA,          /* internal format */
 152                    256,              /* table size */
 153                    GL_RGBA,          /* table format */
 154                    GL_UNSIGNED_BYTE, /* table type */
 155                    table);           /* the color table */
 156 #endif
 157
 158    glTexImage2D(GL_TEXTURE_2D,       /* target */
 159                 0,                   /* level */
 160                 GL_COLOR_INDEX8_EXT, /* internal format */
 161                 WIDTH, HEIGHT,       /* width, height */
 162                 0,                   /* border */
 163                 GL_COLOR_INDEX,      /* texture format */
 164                 GL_UNSIGNED_BYTE,    /* texture type */
 165                 texture);            /* the texture */
 166 #endif
 167
 168    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 169    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 170    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 171    glEnable(GL_TEXTURE_2D);
 172
 173    glEnable(GL_BLEND);
 174    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 175 #undef HEIGHT
 176 #undef WIDTH
 177 }
 178
 179
 180
 181 /*
 182  * Color ramp test
 183  */
 184 static void Init2( void )
 185 {
 186 #define HEIGHT 32
 187 #define WIDTH 256
 188    static char texture[HEIGHT][WIDTH];
 189    GLubyte table[256][4];
 190    int i, j;
 191
 192    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 193       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 194       exit(0);
 195    }
 196
 197    for (j = 0; j < HEIGHT; j++) {
 198       for (i = 0; i < WIDTH; i++) {
 199          texture[j][i] = i;
 200       }
 201    }
 202
 203    for (i = 0; i < 255; i++) {
 204       table[i][0] = i;
 205       table[i][1] = 0;
 206       table[i][2] = 0;
 207       table[i][3] = 255;
 208    }
 209
 210 #ifdef GL_EXT_paletted_texture
 211
 212 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 213    printf("Using shared palette\n");
 214    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 215                    GL_RGBA,          /* internal format */
 216                    256,              /* table size */
 217                    GL_RGBA,          /* table format */
 218                    GL_UNSIGNED_BYTE, /* table type */
 219                    table);           /* the color table */
 220    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 221 #else
 222    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 223                    GL_RGBA,          /* internal format */
 224                    256,              /* table size */
 225                    GL_RGBA,          /* table format */
 226                    GL_UNSIGNED_BYTE, /* table type */
 227                    table);           /* the color table */
 228 #endif
 229
 230    glTexImage2D(GL_TEXTURE_2D,       /* target */
 231                 0,                   /* level */
 232                 GL_COLOR_INDEX8_EXT, /* internal format */
 233                 WIDTH, HEIGHT,       /* width, height */
 234                 0,                   /* border */
 235                 GL_COLOR_INDEX,      /* texture format */
 236                 GL_UNSIGNED_BYTE,    /* texture type */
 237                 texture);            /* teh texture */
 238 #endif
 239
 240    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 241    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 242    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 243    glEnable(GL_TEXTURE_2D);
 244
 245    glEnable(GL_BLEND);
 246    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 247 }
 248
 249
 250 int main( int argc, char *argv[] )
 251 {
 252    glutInit( &argc, argv );
 253    glutInitWindowPosition( 0, 0 );
 254    glutInitWindowSize( 400, 300 );
 255
 256    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 257
 258    glutCreateWindow(argv[0]);
 259
 260    Init();
 261
 262    glutReshapeFunc( Reshape );
 263    glutKeyboardFunc( Key );
 264    glutDisplayFunc( Display );
 265    if (Anim)
 266       glutIdleFunc( Idle );
 267
 268    glutMainLoop();
 269    return 0;
 270 }