progs/demos/paltex.c

   1 /* $Id: paltex.c,v 1.6 2000/10/05 07:17:43 joukj 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 #define GL_GLEXT_LEGACY
  13 #include <GL/glut.h>
  14
  15
  16 static float Rot = 0.0;
  17 static GLboolean Anim = 1;
  18
  19
  20 static void Idle( void )
  21 {
  22    float t = glutGet(GLUT_ELAPSED_TIME) * 0.001;  /* in seconds */
  23    Rot = t * 360 / 4;  /* 1 rotation per 4 seconds */
  24    glutPostRedisplay();
  25 }
  26
  27
  28 static void Display( void )
  29 {
  30    /* draw background gradient */
  31    glDisable(GL_TEXTURE_2D);
  32    glBegin(GL_POLYGON);
  33    glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
  34    glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
  35    glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5,  1.0);
  36    glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5,  1.0);
  37    glEnd();
  38
  39    glPushMatrix();
  40    glRotatef(Rot, 0, 0, 1);
  41
  42    glEnable(GL_TEXTURE_2D);
  43    glBegin(GL_POLYGON);
  44    glTexCoord2f(0, 1);  glVertex2f(-1, -0.5);
  45    glTexCoord2f(1, 1);  glVertex2f( 1, -0.5);
  46    glTexCoord2f(1, 0);  glVertex2f( 1,  0.5);
  47    glTexCoord2f(0, 0);  glVertex2f(-1,  0.5);
  48    glEnd();
  49
  50    glPopMatrix();
  51
  52    glutSwapBuffers();
  53 }
  54
  55
  56 static void Reshape( int width, int height )
  57 {
  58    glViewport( 0, 0, width, height );
  59    glMatrixMode( GL_PROJECTION );
  60    glLoadIdentity();
  61    glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
  62    glMatrixMode( GL_MODELVIEW );
  63    glLoadIdentity();
  64 }
  65
  66
  67 static void Key( unsigned char key, int x, int y )
  68 {
  69    (void) x;
  70    (void) y;
  71    switch (key) {
  72       case 27:
  73          exit(0);
  74          break;
  75       case 's':
  76          Rot += 0.5;
  77          break;
  78       case ' ':
  79          Anim = !Anim;
  80          if (Anim)
  81             glutIdleFunc( Idle );
  82          else
  83             glutIdleFunc( NULL );
  84          break;
  85    }
  86    glutPostRedisplay();
  87 }
  88
  89
  90 static void Init( void )
  91 {
  92 #define HEIGHT 8
  93 #define WIDTH 32
  94    static char texture[HEIGHT][WIDTH] = {
  95          "                                ",
  96          "    MMM    EEEE   SSS    AAA    ",
  97          "   M M M  E      S   S  A   A   ",
  98          "   M M M  EEEE    SS    A   A   ",
  99          "   M M M  E         SS  AAAAA   ",
 100          "   M   M  E      S   S  A   A   ",
 101          "   M   M   EEEE   SSS   A   A   ",
 102          "                                "
 103       };
 104    GLubyte table[256][4];
 105
 106    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 107       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 108       exit(0);
 109    }
 110
 111    /* load the color table for each texel-index */
 112    memset(table, 0, 256*4);
 113    table[' '][0] = 255;
 114    table[' '][1] = 255;
 115    table[' '][2] = 255;
 116    table[' '][3] = 64;
 117    table['M'][0] = 255;
 118    table['M'][1] = 0;
 119    table['M'][2] = 0;
 120    table['M'][3] = 255;
 121    table['E'][0] = 0;
 122    table['E'][1] = 255;
 123    table['E'][2] = 0;
 124    table['E'][3] = 255;
 125    table['S'][0] = 0;
 126    table['S'][1] = 0;
 127    table['S'][2] = 255;
 128    table['S'][3] = 255;
 129    table['A'][0] = 255;
 130    table['A'][1] = 255;
 131    table['A'][2] = 0;
 132    table['A'][3] = 255;
 133
 134 #ifdef GL_EXT_paletted_texture
 135
 136 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 137    printf("Using shared palette\n");
 138    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 139                    GL_RGBA,          /* internal format */
 140                    256,              /* table size */
 141                    GL_RGBA,          /* table format */
 142                    GL_UNSIGNED_BYTE, /* table type */
 143                    table);           /* the color table */
 144    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 145 #else
 146    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 147                    GL_RGBA,          /* internal format */
 148                    256,              /* table size */
 149                    GL_RGBA,          /* table format */
 150                    GL_UNSIGNED_BYTE, /* table type */
 151                    table);           /* the color table */
 152 #endif
 153
 154    glTexImage2D(GL_TEXTURE_2D,       /* target */
 155                 0,                   /* level */
 156                 GL_COLOR_INDEX8_EXT, /* internal format */
 157                 WIDTH, HEIGHT,       /* width, height */
 158                 0,                   /* border */
 159                 GL_COLOR_INDEX,      /* texture format */
 160                 GL_UNSIGNED_BYTE,    /* texture type */
 161                 texture);            /* teh texture */
 162 #endif
 163
 164    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 165    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 166    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 167    glEnable(GL_TEXTURE_2D);
 168
 169    glEnable(GL_BLEND);
 170    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 171 #undef HEIGHT
 172 #undef WIDTH
 173 }
 174
 175
 176
 177 /*
 178  * Color ramp test
 179  */
 180 static void Init2( void )
 181 {
 182 #define HEIGHT 32
 183 #define WIDTH 256
 184    static char texture[HEIGHT][WIDTH];
 185    GLubyte table[256][4];
 186    int i, j;
 187
 188    if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
 189       printf("Sorry, GL_EXT_paletted_texture not supported\n");
 190       exit(0);
 191    }
 192
 193    for (j = 0; j < HEIGHT; j++) {
 194       for (i = 0; i < WIDTH; i++) {
 195          texture[j][i] = i;
 196       }
 197    }
 198
 199    for (i = 0; i < 255; i++) {
 200       table[i][0] = i;
 201       table[i][1] = 0;
 202       table[i][2] = 0;
 203       table[i][3] = 255;
 204    }
 205
 206 #ifdef GL_EXT_paletted_texture
 207
 208 #if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
 209    printf("Using shared palette\n");
 210    glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT,    /* target */
 211                    GL_RGBA,          /* internal format */
 212                    256,              /* table size */
 213                    GL_RGBA,          /* table format */
 214                    GL_UNSIGNED_BYTE, /* table type */
 215                    table);           /* the color table */
 216    glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
 217 #else
 218    glColorTableEXT(GL_TEXTURE_2D,    /* target */
 219                    GL_RGBA,          /* internal format */
 220                    256,              /* table size */
 221                    GL_RGBA,          /* table format */
 222                    GL_UNSIGNED_BYTE, /* table type */
 223                    table);           /* the color table */
 224 #endif
 225
 226    glTexImage2D(GL_TEXTURE_2D,       /* target */
 227                 0,                   /* level */
 228                 GL_COLOR_INDEX8_EXT, /* internal format */
 229                 WIDTH, HEIGHT,       /* width, height */
 230                 0,                   /* border */
 231                 GL_COLOR_INDEX,      /* texture format */
 232                 GL_UNSIGNED_BYTE,    /* texture type */
 233                 texture);            /* teh texture */
 234 #endif
 235
 236    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 237    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 238    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 239    glEnable(GL_TEXTURE_2D);
 240
 241    glEnable(GL_BLEND);
 242    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 243 }
 244
 245
 246 int main( int argc, char *argv[] )
 247 {
 248    glutInit( &argc, argv );
 249    glutInitWindowPosition( 0, 0 );
 250    glutInitWindowSize( 400, 300 );
 251
 252    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 253
 254    glutCreateWindow(argv[0]);
 255
 256    Init();
 257
 258    glutReshapeFunc( Reshape );
 259    glutKeyboardFunc( Key );
 260    glutDisplayFunc( Display );
 261    if (Anim)
 262       glutIdleFunc( Idle );
 263
 264    glutMainLoop();
 265    return 0;
 266 }