progs/demos/texenv.c

   1
   2 /* Copyright (c) Mark J. Kilgard, 1994. */
   3
   4 /**
   5  * (c) Copyright 1993, Silicon Graphics, Inc.
   6  * ALL RIGHTS RESERVED
   7  * Permission to use, copy, modify, and distribute this software for
   8  * any purpose and without fee is hereby granted, provided that the above
   9  * copyright notice appear in all copies and that both the copyright notice
  10  * and this permission notice appear in supporting documentation, and that
  11  * the name of Silicon Graphics, Inc. not be used in advertising
  12  * or publicity pertaining to distribution of the software without specific,
  13  * written prior permission.
  14  *
  15  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  16  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  18  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  19  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  20  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  21  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  22  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  23  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  24  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  25  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  26  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  27  *
  28  * US Government Users Restricted Rights
  29  * Use, duplication, or disclosure by the Government is subject to
  30  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  31  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  32  * clause at DFARS 252.227-7013 and/or in similar or successor
  33  * clauses in the FAR or the DOD or NASA FAR Supplement.
  34  * Unpublished-- rights reserved under the copyright laws of the
  35  * United States.  Contractor/manufacturer is Silicon Graphics,
  36  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  37  *
  38  * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
  39  */
  40
  41 /*
  42  * Demonstrates texture environment modes and internal image formats.
  43  */
  44
  45 /*
  46  * Hacked on, updated by Gareth Hughes <gareth@valinux.com>
  47  */
  48
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <GL/glut.h>
  53
  54 #undef max
  55 #undef min
  56 #define max( a, b )     ((a) >= (b) ? (a) : (b))
  57 #define min( a, b )     ((a) <= (b) ? (a) : (b))
  58
  59 GLfloat lightCheck[4] = { 0.7, 0.7, 0.7, 1.0 };
  60 GLfloat darkCheck[4] = { 0.3, 0.3, 0.3, 1.0 };
  61
  62 GLfloat labelColor0[4] = { 1.0, 1.0, 1.0, 1.0 };
  63 GLfloat labelColor1[4] = { 1.0, 1.0, 0.4, 1.0 };
  64 GLfloat *labelInfoColor = labelColor0;
  65 GLfloat labelLevelColor0[4] = { 0.8, 0.8, 0.1, 1.0 };
  66 GLfloat labelLevelColor1[4] = { 0.0, 0.0, 0.0, 1.0 };
  67
  68 GLboolean doubleBuffered = GL_TRUE;
  69 GLboolean drawBackground = GL_FALSE;
  70 GLboolean drawBlended = GL_TRUE;
  71 GLboolean drawSmooth = GL_FALSE;
  72 GLboolean drawTextured = GL_TRUE;
  73 GLboolean displayLevelInfo = GL_FALSE;
  74
  75 int textureWidth = 64;
  76 int textureHeight = 64;
  77
  78 int winWidth = 580, winHeight = 720;
  79
  80 struct formatInfo {
  81    GLenum       baseFormat;
  82    GLenum       internalFormat;
  83    char         *name;
  84 };
  85
  86 #define NUM_LUMINANCE_FORMATS   (sizeof(luminanceFormats) / sizeof(luminanceFormats[0]))
  87 struct formatInfo luminanceFormats[] =
  88 {
  89    { GL_LUMINANCE, GL_LUMINANCE, "LUMINANCE" },
  90    { GL_LUMINANCE, GL_LUMINANCE4, "LUMINANCE4" },
  91    { GL_LUMINANCE, GL_LUMINANCE8, "LUMINANCE8" },
  92    { GL_LUMINANCE, GL_LUMINANCE12, "LUMINANCE12" },
  93    { GL_LUMINANCE, GL_LUMINANCE16, "LUMINANCE16" },
  94 };
  95
  96 #define NUM_ALPHA_FORMATS       (sizeof(alphaFormats) / sizeof(alphaFormats[0]))
  97 struct formatInfo alphaFormats[] =
  98 {
  99    { GL_ALPHA, GL_ALPHA, "ALPHA" },
 100    { GL_ALPHA, GL_ALPHA4, "ALPHA4" },
 101    { GL_ALPHA, GL_ALPHA8, "ALPHA8" },
 102    { GL_ALPHA, GL_ALPHA12, "ALPHA12" },
 103    { GL_ALPHA, GL_ALPHA16, "ALPHA16" },
 104 };
 105
 106 #define NUM_INTENSITY_FORMATS   (sizeof(intensityFormats) / sizeof(intensityFormats[0]))
 107 struct formatInfo intensityFormats[] =
 108 {
 109    { GL_INTENSITY, GL_INTENSITY, "INTENSITY" },
 110    { GL_INTENSITY, GL_INTENSITY4, "INTENSITY4" },
 111    { GL_INTENSITY, GL_INTENSITY8, "INTENSITY8" },
 112    { GL_INTENSITY, GL_INTENSITY12, "INTENSITY12" },
 113    { GL_INTENSITY, GL_INTENSITY16, "INTENSITY16" },
 114 };
 115
 116 #define NUM_LUMINANCE_ALPHA_FORMATS     (sizeof(luminanceAlphaFormats) / sizeof(luminanceAlphaFormats[0]))
 117 struct formatInfo luminanceAlphaFormats[] =
 118 {
 119    { GL_LUMINANCE_ALPHA, GL_LUMINANCE_ALPHA, "LUMINANCE_ALPHA" },
 120    { GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, "LUMINANCE4_ALPHA4" },
 121    { GL_LUMINANCE_ALPHA, GL_LUMINANCE6_ALPHA2, "LUMINANCE6_ALPHA2" },
 122    { GL_LUMINANCE_ALPHA, GL_LUMINANCE8_ALPHA8, "LUMINANCE8_ALPHA8" },
 123    { GL_LUMINANCE_ALPHA, GL_LUMINANCE12_ALPHA4, "LUMINANCE12_ALPHA4" },
 124    { GL_LUMINANCE_ALPHA, GL_LUMINANCE12_ALPHA12, "LUMINANCE12_ALPHA12" },
 125    { GL_LUMINANCE_ALPHA, GL_LUMINANCE16_ALPHA16, "LUMINANCE16_ALPHA16" },
 126 };
 127
 128 #define NUM_RGB_FORMATS         (sizeof(rgbFormats) / sizeof(rgbFormats[0]))
 129 struct formatInfo rgbFormats[] =
 130 {
 131    { GL_RGB, GL_RGB, "RGB" },
 132    { GL_RGB, GL_R3_G3_B2, "R3_G3_B2" },
 133    { GL_RGB, GL_RGB4, "RGB4" },
 134    { GL_RGB, GL_RGB5, "RGB5" },
 135    { GL_RGB, GL_RGB8, "RGB8" },
 136    { GL_RGB, GL_RGB10, "RGB10" },
 137    { GL_RGB, GL_RGB12, "RGB12" },
 138    { GL_RGB, GL_RGB16, "RGB16" },
 139 };
 140
 141 #define NUM_RGBA_FORMATS        (sizeof(rgbaFormats) / sizeof(rgbaFormats[0]))
 142 struct formatInfo rgbaFormats[] =
 143 {
 144    { GL_RGBA, GL_RGBA, "RGBA" },
 145    { GL_RGBA, GL_RGBA2, "RGBA2" },
 146    { GL_RGBA, GL_RGBA4, "RGBA4" },
 147    { GL_RGBA, GL_RGB5_A1, "RGB5_A1" },
 148    { GL_RGBA, GL_RGBA8, "RGBA8" },
 149    { GL_RGBA, GL_RGB10_A2, "RGB10_A2" },
 150    { GL_RGBA, GL_RGBA12, "RGBA12" },
 151    { GL_RGBA, GL_RGBA16, "RGBA16" },
 152 };
 153
 154 struct baseFormatInfo {
 155    struct       formatInfo *format;
 156    int          current, number;
 157 };
 158
 159 #define NUM_BASE_FORMATS        (sizeof(baseFormats) / sizeof(baseFormats[0]))
 160 int baseFormat;
 161 struct baseFormatInfo baseFormats[] =
 162 {
 163    { luminanceFormats, 0, NUM_LUMINANCE_FORMATS },
 164    { alphaFormats, 0, NUM_ALPHA_FORMATS },
 165    { intensityFormats, 0, NUM_INTENSITY_FORMATS },
 166    { luminanceAlphaFormats, 0, NUM_LUMINANCE_ALPHA_FORMATS },
 167    { rgbFormats, 0, NUM_RGB_FORMATS },
 168    { rgbaFormats, 0, NUM_RGBA_FORMATS },
 169 };
 170
 171 #define NUM_ENV_COLORS          (sizeof(envColors) / sizeof(envColors[0]))
 172 int envColor = 0;
 173 GLfloat envColors[][4] =
 174 {
 175    { 0.0, 0.0, 0.0, 1.0 },
 176    { 1.0, 0.0, 0.0, 1.0 },
 177    { 0.0, 1.0, 0.0, 1.0 },
 178    { 0.0, 0.0, 1.0, 1.0 },
 179    { 1.0, 1.0, 1.0, 1.0 },
 180 };
 181
 182 struct envModeInfo {
 183    GLenum       mode;
 184    char         *name;
 185 };
 186
 187 /* allow for run-time check for GL_EXT_texture_env_add */
 188 int NUM_ENV_MODES = 5;
 189 struct envModeInfo envModes[] =
 190 {
 191    { GL_REPLACE, "REPLACE" },
 192    { GL_MODULATE, "MODULATE" },
 193    { GL_BLEND, "BLEND" },
 194    { GL_DECAL, "DECAL" },
 195 #if GL_EXT_texture_env_add
 196    { GL_ADD, "ADD" },
 197 #endif
 198 };
 199
 200 static void checkErrors( void )
 201 {
 202    GLenum error;
 203
 204    while ( (error = glGetError()) != GL_NO_ERROR ) {
 205       fprintf( stderr, "Error: %s\n", (char *) gluErrorString( error ) );
 206    }
 207 }
 208
 209 static void drawString( const char *string, GLfloat x, GLfloat y,
 210                         const GLfloat color[4] )
 211 {
 212    glColor4fv( color );
 213    glRasterPos2f( x, y );
 214
 215    while ( *string ) {
 216       glutBitmapCharacter( GLUT_BITMAP_TIMES_ROMAN_10, *string );
 217       string++;
 218    }
 219 }
 220
 221 static void drawStringOutline( const char *string, GLfloat x, GLfloat y,
 222                                const GLfloat color[4],
 223                                const GLfloat outline[4] )
 224 {
 225    drawString( string, x - 1, y, outline );
 226    drawString( string, x + 1, y, outline );
 227    drawString( string, x, y - 1, outline );
 228    drawString( string, x, y + 1, outline );
 229    drawString( string, x, y, color );
 230 }
 231
 232 static void begin2D( int width, int height )
 233 {
 234    glMatrixMode( GL_PROJECTION );
 235
 236    glPushMatrix();
 237    glLoadIdentity();
 238
 239    glOrtho( 0, width, 0, height, -1, 1 );
 240    glMatrixMode( GL_MODELVIEW );
 241
 242    glPushMatrix();
 243    glLoadIdentity();
 244 }
 245
 246 static void end2D( void )
 247 {
 248    glMatrixMode( GL_PROJECTION );
 249    glPopMatrix();
 250    glMatrixMode( GL_MODELVIEW );
 251    glPopMatrix();
 252 }
 253
 254 static void initialize( void )
 255 {
 256    glMatrixMode( GL_PROJECTION );
 257    glLoadIdentity();
 258
 259    glOrtho( -1.5, 1.5, -1.5, 1.5, -1.5, 1.5 );
 260
 261    glMatrixMode(GL_MODELVIEW);
 262    glLoadIdentity();
 263
 264    glShadeModel( GL_FLAT );
 265 }
 266
 267 /* ARGSUSED1 */
 268 static void keyboard( unsigned char c, int x, int y )
 269 {
 270    switch ( c ) {
 271    case 'c':
 272       envColor++;
 273       envColor = envColor % (int) NUM_ENV_COLORS;
 274       break;
 275    case 'g':
 276       drawBackground = !drawBackground;
 277       break;
 278    case 'b':
 279       drawBlended = !drawBlended;
 280       break;
 281    case 's':
 282       drawSmooth = !drawSmooth;
 283       break;
 284    case 't':
 285       drawTextured = !drawTextured;
 286       break;
 287    case 'i':
 288       displayLevelInfo = !displayLevelInfo;
 289       break;
 290    case 27:             /* Escape key should force exit. */
 291       exit(0);
 292       break;
 293    default:
 294       break;
 295    }
 296    glutPostRedisplay();
 297 }
 298
 299 /* ARGSUSED1 */
 300 static void special( int key, int x, int y )
 301 {
 302    switch ( key ) {
 303    case GLUT_KEY_DOWN:
 304       if ( ++baseFormat > NUM_BASE_FORMATS - 1 ) {
 305          baseFormat = 0;
 306       }
 307       break;
 308    case GLUT_KEY_UP:
 309       if ( --baseFormat < 0 ) {
 310          baseFormat = NUM_BASE_FORMATS - 1;
 311       }
 312       break;
 313    case GLUT_KEY_LEFT:
 314       --baseFormats[baseFormat].current;
 315       if ( baseFormats[baseFormat].current < 0 ) {
 316          baseFormats[baseFormat].current = baseFormats[baseFormat].number - 1;
 317       }
 318       break;
 319    case GLUT_KEY_RIGHT:
 320       ++baseFormats[baseFormat].current;
 321       if ( baseFormats[baseFormat].current > baseFormats[baseFormat].number - 1 ) {
 322          baseFormats[baseFormat].current = 0;
 323       }
 324       break;
 325    default:
 326       break;
 327    }
 328    glutPostRedisplay();
 329 }
 330
 331 static void
 332 reshape( int w, int h )
 333 {
 334    winWidth = w;
 335    winHeight = h;
 336    /* No need to call glViewPort here since "draw" calls it! */
 337 }
 338
 339 static void loadTexture( int width, int height,
 340                          const struct formatInfo *format )
 341 {
 342    int          luminanceSize = 0;
 343    int          alphaSize = 0;
 344    int          rgbSize = 0;
 345    GLenum       textureFormat;
 346    GLubyte      *texImage, *p;
 347    int          elementsPerGroup, elementSize, groupSize, rowSize;
 348    int          i, j;
 349
 350    switch ( format->baseFormat ) {
 351    case GL_LUMINANCE:
 352       luminanceSize = 1;
 353       textureFormat = GL_LUMINANCE;
 354       break;
 355    case GL_INTENSITY:
 356       luminanceSize = 1;
 357       textureFormat = GL_INTENSITY;
 358       break;
 359    case GL_ALPHA:
 360       alphaSize = 1;
 361       textureFormat = GL_ALPHA;
 362       break;
 363    case GL_LUMINANCE_ALPHA:
 364       luminanceSize = 1;
 365       alphaSize = 1;
 366       textureFormat = GL_LUMINANCE_ALPHA;
 367       break;
 368    case GL_RGB:
 369       rgbSize = 3;
 370       textureFormat = GL_RGB;
 371       break;
 372    case GL_RGBA:
 373       rgbSize = 3;
 374       alphaSize = 1;
 375       textureFormat = GL_RGBA;
 376       break;
 377    default:
 378       fprintf(stderr, "bad internal format info\n");
 379       return;
 380    }
 381
 382    elementsPerGroup = luminanceSize + alphaSize + rgbSize;
 383    elementSize = sizeof(GLubyte);
 384    groupSize = elementsPerGroup * elementSize;
 385    rowSize = width * groupSize;
 386
 387    if ( (texImage = (GLubyte *) malloc( height * rowSize ) ) == NULL ) {
 388       fprintf( stderr, "texture malloc failed\n" );
 389       return;
 390    }
 391
 392    for ( i = 0 ; i < height ; i++ )
 393    {
 394       p = texImage + i * rowSize;
 395
 396       for ( j = 0 ; j < width ; j++ )
 397       {
 398          if ( luminanceSize > 0 )
 399          {
 400             /**
 401              ** +-----+-----+
 402              ** |     |     |
 403              ** |  W  | LG  |
 404              ** |     |     |
 405              ** +-----+-----+
 406              ** |     |     |
 407              ** | DG  |  B  |
 408              ** |     |     |
 409              ** +-----+-----+
 410              **/
 411             if ( i > height / 2 ) {
 412                if ( j < width / 2 ) {
 413                   p[0] = 0xff;
 414                } else {
 415                   p[0] = 0xaa;
 416                }
 417             } else {
 418                if ( j < width / 2 ) {
 419                   p[0] = 0x55;
 420                } else {
 421                   p[0] = 0x00;
 422                }
 423             }
 424             p += elementSize;
 425          }
 426
 427          if ( rgbSize > 0 )
 428          {
 429             /**
 430              ** +-----+-----+
 431              ** |     |     |
 432              ** |  R  |  G  |
 433              ** |     |     |
 434              ** +-----+-----+
 435              ** |     |     |
 436              ** |  Y  |  B  |
 437              ** |     |     |
 438              ** +-----+-----+
 439              **/
 440             if ( i > height / 2 ) {
 441                if ( j < width / 2 ) {
 442                   p[0] = 0xff;
 443                   p[1] = 0x00;
 444                   p[2] = 0x00;
 445                } else {
 446                   p[0] = 0x00;
 447                   p[1] = 0xff;
 448                   p[2] = 0x00;
 449                }
 450             } else {
 451                if ( j < width / 2 ) {
 452                   p[0] = 0xff;
 453                   p[1] = 0xff;
 454                   p[2] = 0x00;
 455                } else {
 456                   p[0] = 0x00;
 457                   p[1] = 0x00;
 458                   p[2] = 0xff;
 459                }
 460             }
 461             p += 3 * elementSize;
 462          }
 463
 464          if ( alphaSize > 0 )
 465          {
 466             /**
 467              ** +-----------+
 468              ** |     W     |
 469              ** |  +-----+  |
 470              ** |  |     |  |
 471              ** |  |  B  |  |
 472              ** |  |     |  |
 473              ** |  +-----+  |
 474              ** |           |
 475              ** +-----------+
 476              **/
 477             int i2 = i - height / 2;
 478             int j2 = j - width / 2;
 479             int h8 = height / 8;
 480             int w8 = width / 8;
 481             if ( -h8 <= i2 && i2 <= h8 && -w8 <= j2 && j2 <= w8 ) {
 482                p[0] = 0x00;
 483             } else if ( -2 * h8 <= i2 && i2 <= 2 * h8 && -2 * w8 <= j2 && j2 <= 2 * w8 ) {
 484                p[0] = 0x55;
 485             } else if ( -3 * h8 <= i2 && i2 <= 3 * h8 && -3 * w8 <= j2 && j2 <= 3 * w8 ) {
 486                p[0] = 0xaa;
 487             } else {
 488                p[0] = 0xff;
 489             }
 490             p += elementSize;
 491          }
 492       }
 493    }
 494
 495    glTexImage2D( GL_TEXTURE_2D, 0,
 496                  format->internalFormat, width, height, 0,
 497                  textureFormat, GL_UNSIGNED_BYTE, texImage );
 498
 499    free( texImage );
 500 }
 501
 502 static void drawCheck( int w, int h, const GLfloat lightCheck[4],
 503                        const GLfloat darkCheck[4] )
 504 {
 505    float        dw = 2.0 / w;
 506    float        dh = 2.0 / h;
 507    int          i, j;
 508
 509    for ( i = 0 ; i < w ; i++ ) {
 510       GLfloat x0 = -1.0 + i * dw;
 511       GLfloat x1 = x0 + dw;
 512
 513       glBegin( GL_QUAD_STRIP );
 514
 515       for ( j = 0 ; j <= h ; j++ ) {
 516          GLfloat y = -1.0 + j * dh;
 517
 518          if ( (i ^ j) & 1 ) {
 519             glColor4fv( lightCheck );
 520          } else {
 521             glColor4fv( darkCheck );
 522          }
 523
 524          glVertex2f( x0, y );
 525          glVertex2f( x1, y );
 526       }
 527
 528       glEnd();
 529    }
 530 }
 531
 532 static const char *lookupFormat( GLint format )
 533 {
 534    switch ( format ) {
 535    case GL_RGBA:
 536       return "GL_RGBA";
 537    case GL_RGB:
 538       return "GL_RGB";
 539    case GL_ALPHA:
 540       return "GL_ALPHA";
 541    case GL_LUMINANCE:
 542       return "GL_LUMINANCE";
 543    case GL_LUMINANCE_ALPHA:
 544       return "GL_LUMINANCE_ALPHA";
 545    case GL_INTENSITY:
 546       return "GL_INTENSITY";
 547    case GL_COLOR_INDEX:
 548       return "GL_COLOR_INDEX";
 549    case GL_BGRA:
 550       return "GL_BGRA";
 551    case GL_BGR:
 552       return "GL_BGR";
 553    default:
 554       return "unknown format";
 555    }
 556 }
 557
 558 static void drawSample( int x, int y, int w, int h,
 559                         const struct formatInfo *format,
 560                         const struct envModeInfo *envMode )
 561 {
 562    glViewport( x, y, w, h );
 563    glScissor( x, y, w, h );
 564
 565    glClearColor( 0.1, 0.1, 0.1, 1.0 );
 566    glClear( GL_COLOR_BUFFER_BIT );
 567
 568    begin2D( w, h );
 569    drawString( format->name, 10, h - 15, labelInfoColor );
 570    drawString( envMode->name, 10, 5, labelInfoColor );
 571    end2D();
 572
 573    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, envMode->mode );
 574    glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, envColors[envColor] );
 575
 576    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 577    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 578
 579    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP );
 580    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP );
 581
 582    loadTexture( textureWidth, textureHeight, format );
 583
 584    if ( drawBackground ) {
 585       drawCheck( 15, 15, lightCheck, darkCheck );
 586    }
 587    if ( drawBlended ) {
 588       glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 589       glEnable( GL_BLEND );
 590    }
 591    if ( drawSmooth ) {
 592       glShadeModel( GL_SMOOTH );
 593    }
 594    else {
 595       glShadeModel( GL_FLAT );
 596       glColor4f(1, 1, 1, 1);
 597    }
 598    if ( drawTextured ) {
 599       glEnable( GL_TEXTURE_2D );
 600    }
 601
 602    /*
 603     * if (drawSmooth) then draw quad which goes from purple at the
 604     * bottom (100% alpha) to green at the top (50% alpha).
 605     */
 606    glBegin( GL_QUADS );
 607       if ( drawSmooth )  glColor4f( 1.0, 0.0, 1.0, 1.0 );
 608       glTexCoord2f( 0.0, 0.0 );
 609       glVertex2f( -0.8, -0.8 );
 610
 611       if ( drawSmooth )  glColor4f( 1.0, 0.0, 1.0, 1.0 );
 612       glTexCoord2f( 1.0, 0.0 );
 613       glVertex2f( 0.8, -0.8 );
 614
 615       if ( drawSmooth )  glColor4f( 0.0, 1.0, 0.0, 0.5 );
 616       glTexCoord2f( 1.0, 1.0 );
 617       glVertex2f( 0.8, 0.8 );
 618
 619       if ( drawSmooth )  glColor4f( 0.0, 1.0, 0.0, 0.5 );
 620       glTexCoord2f( 0.0, 1.0 );
 621       glVertex2f( -0.8, 0.8 );
 622    glEnd();
 623
 624    glDisable( GL_BLEND );
 625    glShadeModel( GL_FLAT );
 626    glDisable( GL_TEXTURE_2D );
 627
 628    if ( envMode->mode == GL_DECAL &&
 629         (format->baseFormat == GL_ALPHA ||
 630          format->baseFormat == GL_LUMINANCE ||
 631          format->baseFormat == GL_LUMINANCE_ALPHA ||
 632          format->baseFormat == GL_INTENSITY)) {
 633       /* undefined format/mode combination */
 634       begin2D( w, h );
 635       drawStringOutline( "UNDEFINED MODE", 15, h / 2,
 636                          labelLevelColor0, labelLevelColor1 );
 637       end2D();
 638    }
 639    else if ( displayLevelInfo ) {
 640       GLint width, height, border, format;
 641       GLint redSize, greenSize, blueSize, alphaSize;
 642       GLint luminanceSize, intensitySize;
 643       char buf[255];
 644
 645       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &width );
 646       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &height );
 647       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_BORDER, &border );
 648       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, &format );
 649       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_RED_SIZE, &redSize );
 650       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_GREEN_SIZE, &greenSize );
 651       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_BLUE_SIZE, &blueSize );
 652       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_ALPHA_SIZE, &alphaSize );
 653       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_LUMINANCE_SIZE, &luminanceSize );
 654       glGetTexLevelParameteriv( GL_TEXTURE_2D, 0, GL_TEXTURE_INTENSITY_SIZE, &intensitySize );
 655
 656       begin2D( w, h );
 657       sprintf( buf, "dimensions: %d x %d", width, height );
 658       drawStringOutline( buf, 15, h / 2 + 20, labelLevelColor0, labelLevelColor1 );
 659
 660       sprintf( buf, "border: %d", border );
 661       drawStringOutline( buf, 15, h / 2 + 10, labelLevelColor0, labelLevelColor1 );
 662
 663       sprintf( buf, "internal format:" );
 664       drawStringOutline( buf, 15, h / 2, labelLevelColor0, labelLevelColor1 );
 665
 666       sprintf( buf, "  %s",  lookupFormat( format ) );
 667       drawStringOutline( buf, 15, h / 2 - 10, labelLevelColor0, labelLevelColor1 );
 668
 669       sprintf( buf, "sizes:" );
 670       drawStringOutline( buf, 15, h / 2 - 20, labelLevelColor0, labelLevelColor1 );
 671
 672       sprintf( buf, "  %d / %d / %d / %d / %d / %d",
 673                redSize, greenSize, blueSize, alphaSize,
 674                luminanceSize, intensitySize );
 675       drawStringOutline( buf, 15, h / 2 - 30, labelLevelColor0, labelLevelColor1 );
 676
 677       end2D();
 678    }
 679 }
 680
 681 static void display( void )
 682 {
 683    int          numX = NUM_ENV_MODES, numY = NUM_BASE_FORMATS;
 684    float        xBase = (float) winWidth * 0.01;
 685    float        xOffset = (winWidth - xBase) / numX;
 686    float        xSize = max( xOffset - xBase, 1 );
 687    float        yBase = (float) winHeight * 0.01;
 688    float        yOffset = (winHeight - yBase) / numY;
 689    float        ySize = max( yOffset - yBase, 1 );
 690    float        x, y;
 691    int          i, j;
 692
 693    glViewport( 0, 0, winWidth, winHeight );
 694    glDisable( GL_SCISSOR_TEST );
 695    glClearColor( 0.0, 0.0, 0.0, 0.0 );
 696    glClear( GL_COLOR_BUFFER_BIT );
 697    glEnable( GL_SCISSOR_TEST );
 698
 699    x = xBase;
 700    y = (winHeight - 1) - yOffset;
 701
 702    for ( i = 0 ; i < NUM_BASE_FORMATS ; i++ )
 703    {
 704       struct formatInfo *format;
 705
 706       if ( i == baseFormat ) {
 707          labelInfoColor = labelColor1;
 708       } else {
 709          labelInfoColor = labelColor0;
 710       }
 711
 712       format = &baseFormats[i].format[baseFormats[i].current];
 713
 714       for ( j = 0 ; j < NUM_ENV_MODES ; j++ ) {
 715          struct envModeInfo *envMode;
 716
 717          envMode = &envModes[j];
 718          drawSample( x, y, xSize, ySize, format, envMode );
 719          x += xOffset;
 720       }
 721
 722       x = xBase;
 723       y -= yOffset;
 724    }
 725
 726    if ( doubleBuffered ) {
 727       glutSwapBuffers();
 728    } else {
 729       glFlush();
 730    }
 731
 732    checkErrors();
 733 }
 734
 735 static void usage( char *name )
 736 {
 737    fprintf( stderr, "usage: %s [ options ]\n", name );
 738    fprintf( stderr, "\n" );
 739    fprintf( stderr, "options:\n" );
 740    fprintf( stderr, "    -sb    single buffered\n" );
 741    fprintf( stderr, "    -db    double buffered\n" );
 742    fprintf( stderr, "    -info  print OpenGL driver info\n" );
 743 }
 744
 745 static void instructions( void )
 746 {
 747    fprintf( stderr, "texenv - texture environment and internal format test\n" );
 748    fprintf( stderr, "\n" );
 749    fprintf( stderr, "  [c] - cycle through background colors\n" );
 750    fprintf( stderr, "  [g] - toggle background\n" );
 751    fprintf( stderr, "  [b] - toggle blend\n" );
 752    fprintf( stderr, "  [s] - toggle smooth shading\n" );
 753    fprintf( stderr, "  [t] - toggle texturing\n" );
 754    fprintf( stderr, "  [i] - toggle information display\n" );
 755    fprintf( stderr, "  up/down - select row\n" );
 756    fprintf( stderr, "  left/right - change row's internal format\n" );
 757 }
 758
 759 int main( int argc, char *argv[] )
 760 {
 761    GLboolean info = GL_FALSE;
 762    int i;
 763
 764    glutInit( &argc, argv );
 765
 766    for ( i = 1 ; i < argc ; i++ ) {
 767       if ( !strcmp( "-sb", argv[i] ) ) {
 768          doubleBuffered = GL_FALSE;
 769       } else if ( !strcmp( "-db", argv[i] ) ) {
 770          doubleBuffered = GL_TRUE;
 771       } else if ( !strcmp( "-info", argv[i] ) ) {
 772          info = GL_TRUE;
 773       } else {
 774          usage( argv[0] );
 775          exit( 1 );
 776       }
 777    }
 778
 779    if ( doubleBuffered ) {
 780       glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 781    } else {
 782       glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE );
 783    }
 784
 785    glutInitWindowSize( winWidth, winHeight );
 786    glutInitWindowPosition( 0, 0 );
 787    glutCreateWindow( "Texture Environment Test" );
 788
 789    initialize();
 790    instructions();
 791
 792    if ( info ) {
 793       printf( "\n" );
 794       printf( "GL_RENDERER   = %s\n", (char *) glGetString( GL_RENDERER ) );
 795       printf( "GL_VERSION    = %s\n", (char *) glGetString( GL_VERSION ) );
 796       printf( "GL_VENDOR     = %s\n", (char *) glGetString( GL_VENDOR ) ) ;
 797       printf( "GL_EXTENSIONS = %s\n", (char *) glGetString( GL_EXTENSIONS ) );
 798    }
 799
 800 #if GL_EXT_texture_env_add
 801    if ( !glutExtensionSupported( "GL_EXT_texture_env_add" ) ) {
 802       fprintf( stderr, "missing extension: GL_EXT_texture_env_add\n" );
 803       NUM_ENV_MODES--;
 804    }
 805 #endif
 806
 807    glutDisplayFunc( display );
 808    glutReshapeFunc( reshape );
 809    glutKeyboardFunc( keyboard );
 810    glutSpecialFunc( special );
 811    glutMainLoop();
 812
 813    return 0;
 814 }