progs/tests/texgenmix.c

   1
   2 /*
   3  * Demonstrates mixed texgen/non-texgen texture coordinates.
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <GL/glut.h>
  10
  11 #undef max
  12 #undef min
  13 #define max( a, b )     ((a) >= (b) ? (a) : (b))
  14 #define min( a, b )     ((a) <= (b) ? (a) : (b))
  15
  16 GLfloat labelColor0[4] = { 1.0, 1.0, 1.0, 1.0 };
  17 GLfloat labelColor1[4] = { 1.0, 1.0, 0.4, 1.0 };
  18 GLfloat *labelInfoColor = labelColor0;
  19
  20 GLboolean doubleBuffered = GL_TRUE;
  21 GLboolean drawTextured = GL_TRUE;
  22
  23 int textureWidth = 64;
  24 int textureHeight = 64;
  25
  26 int winWidth = 580, winHeight = 720;
  27
  28 const GLfloat texmat_swap_rq[16] = { 1.0, 0.0, 0.0, 0.0,
  29                                      0.0, 1.0, 0.0, 0.0,
  30                                      0.0, 0.0, 0.0, 1.0,
  31                                      0.0, 0.0, 1.0, 0.0};
  32
  33 const GLfloat nullPlane[4] = { 0.0, 0.0, 0.0, 0.0 };
  34 const GLfloat ObjPlaneS1[4] = { 1.0, 0.0, 1.0, 0.0 };
  35 const GLfloat ObjPlaneS2[4] = { 0.5, 0.0, 0.0, 0.0 };
  36 const GLfloat ObjPlaneS3[4] = { 1.0, 0.0, 0.0, 0.0 };
  37 const GLfloat ObjPlaneT[4] = { 0.0, 1.0, 0.0, 0.0 };
  38 const GLfloat ObjPlaneT2[4] = { 0.0, 0.5, 0.0, 0.0 };
  39 const GLfloat ObjPlaneT3[4] = { 0.0, 1.0, 0.0, 0.0 };
  40 const GLfloat ObjPlaneR[4] = { 0.0, 0.0, 1.0, 0.0 };
  41 const GLfloat ObjPlaneQ[4] = { 0.0, 0.0, 0.0, 0.5 };
  42
  43
  44 static void checkErrors( void )
  45 {
  46    GLenum error;
  47
  48    while ( (error = glGetError()) != GL_NO_ERROR ) {
  49       fprintf( stderr, "Error: %s\n", (char *) gluErrorString( error ) );
  50    }
  51 }
  52
  53 static void drawString( const char *string, GLfloat x, GLfloat y,
  54                         const GLfloat color[4] )
  55 {
  56    glColor4fv( color );
  57    glRasterPos2f( x, y );
  58
  59    while ( *string ) {
  60       glutBitmapCharacter( GLUT_BITMAP_TIMES_ROMAN_10, *string );
  61       string++;
  62    }
  63 }
  64
  65 static void begin2D( int width, int height )
  66 {
  67    glMatrixMode( GL_PROJECTION );
  68
  69    glPushMatrix();
  70    glLoadIdentity();
  71
  72    glOrtho( 0, width, 0, height, -1, 1 );
  73    glMatrixMode( GL_MODELVIEW );
  74
  75    glPushMatrix();
  76    glLoadIdentity();
  77 }
  78
  79 static void end2D( void )
  80 {
  81    glMatrixMode( GL_PROJECTION );
  82    glPopMatrix();
  83    glMatrixMode( GL_MODELVIEW );
  84    glPopMatrix();
  85 }
  86
  87 static void initialize( void )
  88 {
  89    glMatrixMode( GL_PROJECTION );
  90    glLoadIdentity();
  91
  92    glOrtho( -1.5, 1.5, -1.5, 1.5, -1.5, 1.5 );
  93
  94    glMatrixMode(GL_MODELVIEW);
  95    glLoadIdentity();
  96
  97    glShadeModel( GL_FLAT );
  98 }
  99
 100 /* ARGSUSED1 */
 101 static void keyboard( unsigned char c, int x, int y )
 102 {
 103    switch ( c ) {
 104    case 't':
 105       drawTextured = !drawTextured;
 106       break;
 107    case 27:             /* Escape key should force exit. */
 108       exit(0);
 109       break;
 110    default:
 111       break;
 112    }
 113    glutPostRedisplay();
 114 }
 115
 116 /* ARGSUSED1 */
 117 static void special( int key, int x, int y )
 118 {
 119    switch ( key ) {
 120    case GLUT_KEY_DOWN:
 121       break;
 122    case GLUT_KEY_UP:
 123       break;
 124    case GLUT_KEY_LEFT:
 125       break;
 126    case GLUT_KEY_RIGHT:
 127       break;
 128    default:
 129       break;
 130    }
 131    glutPostRedisplay();
 132 }
 133
 134 static void
 135 reshape( int w, int h )
 136 {
 137    winWidth = w;
 138    winHeight = h;
 139    /* No need to call glViewPort here since "draw" calls it! */
 140 }
 141
 142 static void loadTexture( int width, int height )
 143 {
 144    int          alphaSize = 1;
 145    int          rgbSize = 3;
 146    GLubyte      *texImage, *p;
 147    int          elementsPerGroup, elementSize, groupSize, rowSize;
 148    int          i, j;
 149
 150
 151    elementsPerGroup = alphaSize + rgbSize;
 152    elementSize = sizeof(GLubyte);
 153    groupSize = elementsPerGroup * elementSize;
 154    rowSize = width * groupSize;
 155
 156    if ( (texImage = (GLubyte *) malloc( height * rowSize ) ) == NULL ) {
 157       fprintf( stderr, "texture malloc failed\n" );
 158       return;
 159    }
 160
 161    for ( i = 0 ; i < height ; i++ )
 162    {
 163       p = texImage + i * rowSize;
 164
 165       for ( j = 0 ; j < width ; j++ )
 166       {
 167          if ( rgbSize > 0 )
 168          {
 169             /**
 170              ** +-----+-----+
 171              ** |     |     |
 172              ** |  R  |  G  |
 173              ** |     |     |
 174              ** +-----+-----+
 175              ** |     |     |
 176              ** |  Y  |  B  |
 177              ** |     |     |
 178              ** +-----+-----+
 179              **/
 180             if ( i > height / 2 ) {
 181                if ( j < width / 2 ) {
 182                   p[0] = 0xff;
 183                   p[1] = 0x00;
 184                   p[2] = 0x00;
 185                } else {
 186                   p[0] = 0x00;
 187                   p[1] = 0xff;
 188                   p[2] = 0x00;
 189                }
 190             } else {
 191                if ( j < width / 2 ) {
 192                   p[0] = 0xff;
 193                   p[1] = 0xff;
 194                   p[2] = 0x00;
 195                } else {
 196                   p[0] = 0x00;
 197                   p[1] = 0x00;
 198                   p[2] = 0xff;
 199                }
 200             }
 201             p += 3 * elementSize;
 202          }
 203
 204          if ( alphaSize > 0 )
 205          {
 206             /**
 207              ** +-----------+
 208              ** |     W     |
 209              ** |  +-----+  |
 210              ** |  |     |  |
 211              ** |  |  B  |  |
 212              ** |  |     |  |
 213              ** |  +-----+  |
 214              ** |           |
 215              ** +-----------+
 216              **/
 217             int i2 = i - height / 2;
 218             int j2 = j - width / 2;
 219             int h8 = height / 8;
 220             int w8 = width / 8;
 221             if ( -h8 <= i2 && i2 <= h8 && -w8 <= j2 && j2 <= w8 ) {
 222                p[0] = 0x00;
 223             } else if ( -2 * h8 <= i2 && i2 <= 2 * h8 && -2 * w8 <= j2 && j2 <= 2 * w8 ) {
 224                p[0] = 0x55;
 225             } else if ( -3 * h8 <= i2 && i2 <= 3 * h8 && -3 * w8 <= j2 && j2 <= 3 * w8 ) {
 226                p[0] = 0xaa;
 227             } else {
 228                p[0] = 0xff;
 229             }
 230             p += elementSize;
 231          }
 232       }
 233    }
 234
 235    glTexImage2D( GL_TEXTURE_2D, 0,
 236                  GL_RGBA, width, height, 0,
 237                  GL_RGBA, GL_UNSIGNED_BYTE, texImage );
 238
 239    free( texImage );
 240 }
 241
 242
 243 static void drawSample( int x, int y, int w, int h,
 244                         int texgenenabled, int coordnr )
 245 {
 246    char buf[255];
 247
 248    glViewport( x, y, w, h );
 249    glScissor( x, y, w, h );
 250
 251    glClearColor( 0.1, 0.1, 0.1, 1.0 );
 252    glClear( GL_COLOR_BUFFER_BIT );
 253
 254    begin2D( w, h );
 255    if (texgenenabled == 2) {
 256       sprintf( buf, "TexCoord%df", coordnr);
 257       drawString( buf, 10, h - 15, labelInfoColor );
 258       sprintf( buf, "texgen enabled for %s coordinate(s)", coordnr == 2 ? "S" : "S/T");
 259       drawString( buf, 10, 5, labelInfoColor );
 260    }
 261    else if (texgenenabled == 0) {
 262       sprintf( buf, "TexCoord%df", coordnr);
 263       drawString( buf, 10, h - 15, labelInfoColor );
 264       drawString( "no texgen", 10, 5, labelInfoColor );
 265    }
 266    else if (texgenenabled == 1) {
 267       drawString( "no TexCoord", 10, h - 15, labelInfoColor );
 268       sprintf( buf, "texgen enabled for %s coordinate(s)",
 269          coordnr == 2 ? "S/T" : (coordnr == 3 ? "S/T/R" : "S/T/R/Q"));
 270       drawString( buf, 10, 5, labelInfoColor );
 271    }
 272
 273    end2D();
 274
 275    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
 276
 277    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 278    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 279
 280    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
 281    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );
 282
 283    loadTexture( textureWidth, textureHeight );
 284
 285    if ( drawTextured ) {
 286       glEnable( GL_TEXTURE_2D );
 287    }
 288
 289    glDisable( GL_TEXTURE_GEN_S );
 290    glDisable( GL_TEXTURE_GEN_T );
 291    glDisable( GL_TEXTURE_GEN_R );
 292    glDisable( GL_TEXTURE_GEN_Q );
 293
 294    glMatrixMode( GL_TEXTURE );
 295    glLoadIdentity();
 296    glMatrixMode( GL_MODELVIEW );
 297    glPushMatrix();
 298
 299    switch (coordnr) {
 300    case 2:
 301       switch (texgenenabled) {
 302       case 0:
 303          glBegin( GL_QUADS );
 304          glTexCoord2f( 0.0, 0.0 );
 305          glVertex2f( -0.8, -0.8 );
 306
 307          glTexCoord2f( 1.0, 0.0 );
 308          glVertex2f( 0.8, -0.8 );
 309
 310          glTexCoord2f( 1.0, 1.0 );
 311          glVertex2f( 0.8, 0.8 );
 312
 313          glTexCoord2f( 0.0, 1.0 );
 314          glVertex2f( -0.8, 0.8 );
 315          glEnd();
 316          break;
 317       case 1:
 318          glTranslatef( -0.8, -0.8, 0.0 );
 319          glScalef( 1.6, 1.6, 1.0 );
 320          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 321          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 322          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 323          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 324          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS3);
 325          glTexGenfv(GL_T, GL_OBJECT_PLANE, ObjPlaneT3);
 326          glTexGenfv(GL_R, GL_OBJECT_PLANE, nullPlane);
 327          glTexGenfv(GL_Q, GL_OBJECT_PLANE, nullPlane);
 328
 329          glEnable( GL_TEXTURE_GEN_S );
 330          glEnable( GL_TEXTURE_GEN_T );
 331
 332          /* Issue a texcoord here to be sure Q isn't left over from a
 333           * previous sample.
 334           */
 335          glTexCoord1f( 0.0 );
 336          glBegin( GL_QUADS );
 337          glVertex2f( 0.0, 0.0 );
 338          glVertex2f( 1.0, 0.0 );
 339          glVertex2f( 1.0, 1.0 );
 340          glVertex2f( 0.0, 1.0 );
 341          glEnd();
 342          break;
 343       case 2:
 344          /* make sure that texgen T and non-texgen S coordinate are wrong */
 345          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 346          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 347          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 348          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 349          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS1);
 350          glTexGenfv(GL_T, GL_OBJECT_PLANE, nullPlane);
 351          glTexGenfv(GL_R, GL_OBJECT_PLANE, nullPlane);
 352          glTexGenfv(GL_Q, GL_OBJECT_PLANE, nullPlane);
 353
 354          glEnable( GL_TEXTURE_GEN_S );
 355
 356          glBegin( GL_QUADS );
 357          /* use z coordinate to get correct texgen values... */
 358          glTexCoord2f( 0.0, 0.0 );
 359          glVertex3f( -0.8, -0.8, 0.8 );
 360
 361          glTexCoord2f( 0.0, 0.0 );
 362          glVertex3f( 0.8, -0.8, 0.2 );
 363
 364          glTexCoord2f( 0.0, 1.0 );
 365          glVertex3f( 0.8, 0.8, 0.2 );
 366
 367          glTexCoord2f( 0.0, 1.0 );
 368          glVertex3f( -0.8, 0.8, 0.8 );
 369          glEnd();
 370          break;
 371       }
 372       break;
 373    case 3:
 374       glMatrixMode( GL_TEXTURE );
 375       glLoadMatrixf( texmat_swap_rq );
 376       glMatrixMode( GL_MODELVIEW );
 377       glTranslatef( -0.8, -0.8, 0.0 );
 378       glScalef( 1.6, 1.6, 1.0 );
 379       switch (texgenenabled) {
 380       case 0:
 381          glBegin( GL_QUADS );
 382          glTexCoord3f( 0.0, 0.0, 0.5 );
 383          glVertex2f( 0.0, 0.0 );
 384
 385          glTexCoord3f( 0.5, 0.0, 0.5 );
 386          glVertex2f( 1.0, 0.0 );
 387
 388          glTexCoord3f( 0.5, 0.5, 0.5 );
 389          glVertex2f( 1.0, 1.0 );
 390
 391          glTexCoord3f( 0.0, 0.5, 0.5 );
 392          glVertex2f( 0.0, 1.0 );
 393          glEnd();
 394          break;
 395       case 1:
 396          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 397          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 398          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 399          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 400          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS2);
 401          glTexGenfv(GL_T, GL_OBJECT_PLANE, ObjPlaneT2);
 402          glTexGenfv(GL_R, GL_OBJECT_PLANE, ObjPlaneR);
 403          glTexGenfv(GL_Q, GL_OBJECT_PLANE, nullPlane);
 404
 405          glEnable( GL_TEXTURE_GEN_S );
 406          glEnable( GL_TEXTURE_GEN_T );
 407          glEnable( GL_TEXTURE_GEN_R );
 408
 409          glTexCoord1f( 0.0 ); /* to make sure Q is 1.0 */
 410          glBegin( GL_QUADS );
 411          glVertex3f( 0.0, 0.0, 0.5 );
 412          glVertex3f( 1.0, 0.0, 0.5 );
 413          glVertex3f( 1.0, 1.0, 0.5 );
 414          glVertex3f( 0.0, 1.0, 0.5 );
 415          glEnd();
 416          break;
 417       case 2:
 418          /* make sure that texgen R/Q and non-texgen S/T coordinates are wrong */
 419          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 420          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 421          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 422          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 423          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS2);
 424          glTexGenfv(GL_T, GL_OBJECT_PLANE, ObjPlaneT2);
 425          glTexGenfv(GL_R, GL_OBJECT_PLANE, nullPlane);
 426          glTexGenfv(GL_Q, GL_OBJECT_PLANE, nullPlane);
 427
 428          glEnable( GL_TEXTURE_GEN_S );
 429          glEnable( GL_TEXTURE_GEN_T );
 430
 431          glBegin( GL_QUADS );
 432          glTexCoord3f( 0.0, 0.0, 0.5 );
 433          glVertex2f( 0.0, 0.0);
 434
 435          glTexCoord3f( 0.0, 0.0, 0.5 );
 436          glVertex2f( 1.0, 0.0);
 437
 438          glTexCoord3f( 0.0, 0.0, 0.5 );
 439          glVertex2f( 1.0, 1.0);
 440
 441          glTexCoord3f( 0.0, 0.0, 0.5 );
 442          glVertex2f( 0.0, 1.0);
 443          glEnd();
 444          break;
 445       }
 446       break;
 447    case 4:
 448       switch (texgenenabled) {
 449       case 0:
 450          glBegin( GL_QUADS );
 451          /* don't need r coordinate but still setting it I'm mean */
 452          glTexCoord4f( 0.0, 0.0, 0.0, 0.5 );
 453          glVertex2f( -0.8, -0.8 );
 454
 455          glTexCoord4f( 0.5, 0.0, 0.2, 0.5 );
 456          glVertex2f( 0.8, -0.8 );
 457
 458          glTexCoord4f( 0.5, 0.5, 0.5, 0.5 );
 459          glVertex2f( 0.8, 0.8 );
 460
 461          glTexCoord4f( 0.0, 0.5, 0.5, 0.5 );
 462          glVertex2f( -0.8, 0.8 );
 463          glEnd();
 464          break;
 465       case 1:
 466          glTranslatef( -0.8, -0.8, 0.0 );
 467          glScalef( 1.6, 1.6, 1.0 );
 468          /* make sure that texgen R/Q and non-texgen S/T coordinates are wrong */
 469          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 470          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 471          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 472          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 473          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS2);
 474          glTexGenfv(GL_T, GL_OBJECT_PLANE, ObjPlaneT2);
 475          glTexGenfv(GL_R, GL_OBJECT_PLANE, ObjPlaneR);
 476          glTexGenfv(GL_Q, GL_OBJECT_PLANE, ObjPlaneQ);
 477
 478          glEnable( GL_TEXTURE_GEN_S );
 479          glEnable( GL_TEXTURE_GEN_T );
 480          glEnable( GL_TEXTURE_GEN_R );
 481          glEnable( GL_TEXTURE_GEN_Q );
 482
 483          glBegin( GL_QUADS );
 484          glVertex2f( 0.0, 0.0 );
 485          glVertex2f( 1.0, 0.0 );
 486          glVertex2f( 1.0, 1.0 );
 487          glVertex2f( 0.0, 1.0 );
 488          glEnd();
 489          break;
 490       case 2:
 491          glTranslatef( -0.8, -0.8, 0.0 );
 492          glScalef( 1.6, 1.6, 1.0 );
 493          /* make sure that texgen R/Q and non-texgen S/T coordinates are wrong */
 494          glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 495          glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 496          glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 497          glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
 498          glTexGenfv(GL_S, GL_OBJECT_PLANE, ObjPlaneS2);
 499          glTexGenfv(GL_T, GL_OBJECT_PLANE, ObjPlaneT2);
 500          glTexGenfv(GL_R, GL_OBJECT_PLANE, nullPlane);
 501          glTexGenfv(GL_Q, GL_OBJECT_PLANE, nullPlane);
 502
 503          glEnable( GL_TEXTURE_GEN_S );
 504          glEnable( GL_TEXTURE_GEN_T );
 505
 506          glBegin( GL_QUADS );
 507          glTexCoord4f( 0.0, 0.0, 0.0, 0.5 );
 508          glVertex2f( 0.0, 0.0 );
 509
 510          glTexCoord4f( 0.0, 0.0, 0.2, 0.5 );
 511          glVertex2f( 1.0, 0.0 );
 512
 513          glTexCoord4f( 0.0, 0.0, 0.5, 0.5 );
 514          glVertex2f( 1.0, 1.0 );
 515
 516          glTexCoord4f( 0.0, 0.0, 0.75, 0.5 );
 517          glVertex2f( 0.0, 1.0 );
 518          glEnd();
 519          break;
 520       }
 521       break;
 522    }
 523
 524    glPopMatrix();
 525    glDisable( GL_TEXTURE_2D );
 526
 527 }
 528
 529 static void display( void )
 530 {
 531    int          numX = 3, numY = 3;
 532    float        xBase = (float) winWidth * 0.01;
 533    float        xOffset = (winWidth - xBase) / numX;
 534    float        xSize = max( xOffset - xBase, 1 );
 535    float        yBase = (float) winHeight * 0.01;
 536    float        yOffset = (winHeight - yBase) / numY;
 537    float        ySize = max( yOffset - yBase, 1 );
 538    float        x, y;
 539    int          i, j;
 540
 541    glViewport( 0, 0, winWidth, winHeight );
 542    glDisable( GL_SCISSOR_TEST );
 543    glClearColor( 0.0, 0.0, 0.0, 0.0 );
 544    glClear( GL_COLOR_BUFFER_BIT );
 545    glEnable( GL_SCISSOR_TEST );
 546
 547    x = xBase;
 548    y = (winHeight - 1) - yOffset;
 549
 550    for ( i = 0 ; i < numY ; i++ )
 551    {
 552
 553       labelInfoColor = labelColor1;
 554
 555
 556       for ( j = 0 ; j < numX ; j++ ) {
 557          drawSample( x, y, xSize, ySize, i, j+2 );
 558          x += xOffset;
 559       }
 560
 561       x = xBase;
 562       y -= yOffset;
 563    }
 564
 565    if ( doubleBuffered ) {
 566       glutSwapBuffers();
 567    } else {
 568       glFlush();
 569    }
 570
 571    checkErrors();
 572 }
 573
 574 static void usage( char *name )
 575 {
 576    fprintf( stderr, "usage: %s [ options ]\n", name );
 577    fprintf( stderr, "\n" );
 578    fprintf( stderr, "options:\n" );
 579    fprintf( stderr, "    -sb    single buffered\n" );
 580    fprintf( stderr, "    -db    double buffered\n" );
 581    fprintf( stderr, "    -info  print OpenGL driver info\n" );
 582 }
 583
 584 static void instructions( void )
 585 {
 586    fprintf( stderr, "texgenmix - mixed texgen/non-texgen texture coordinate test\n" );
 587    fprintf( stderr, "all quads should look the same!\n" );
 588    fprintf( stderr, "\n" );
 589    fprintf( stderr, "  [t] - toggle texturing\n" );
 590 }
 591
 592 int main( int argc, char *argv[] )
 593 {
 594    GLboolean info = GL_FALSE;
 595    int i;
 596
 597    glutInit( &argc, argv );
 598
 599    for ( i = 1 ; i < argc ; i++ ) {
 600       if ( !strcmp( "-sb", argv[i] ) ) {
 601          doubleBuffered = GL_FALSE;
 602       } else if ( !strcmp( "-db", argv[i] ) ) {
 603          doubleBuffered = GL_TRUE;
 604       } else if ( !strcmp( "-info", argv[i] ) ) {
 605          info = GL_TRUE;
 606       } else {
 607          usage( argv[0] );
 608          exit( 1 );
 609       }
 610    }
 611
 612    if ( doubleBuffered ) {
 613       glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 614    } else {
 615       glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE );
 616    }
 617
 618    glutInitWindowSize( winWidth, winHeight );
 619    glutInitWindowPosition( 0, 0 );
 620    glutCreateWindow( "Mixed texgen/non-texgen texture coordinate test" );
 621
 622    initialize();
 623    instructions();
 624
 625    if ( info ) {
 626       printf( "\n" );
 627       printf( "GL_RENDERER   = %s\n", (char *) glGetString( GL_RENDERER ) );
 628       printf( "GL_VERSION    = %s\n", (char *) glGetString( GL_VERSION ) );
 629       printf( "GL_VENDOR     = %s\n", (char *) glGetString( GL_VENDOR ) ) ;
 630       printf( "GL_EXTENSIONS = %s\n", (char *) glGetString( GL_EXTENSIONS ) );
 631    }
 632
 633    glutDisplayFunc( display );
 634    glutReshapeFunc( reshape );
 635    glutKeyboardFunc( keyboard );
 636    glutSpecialFunc( special );
 637    glutMainLoop();
 638
 639    return 0;
 640 }