progs/demos/cubemap.c

   1 /*
   2  * GL_ARB_texture_cube_map demo
   3  *
   4  * Brian Paul
   5  * May 2000
   6  *
   7  *
   8  * Copyright (C) 2000  Brian Paul   All Rights Reserved.
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a
  11  * copy of this software and associated documentation files (the "Software"),
  12  * to deal in the Software without restriction, including without limitation
  13  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  14  * and/or sell copies of the Software, and to permit persons to whom the
  15  * Software is furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included
  18  * in all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  21  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  23  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  24  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  25  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  */
  27
  28
  29 /*
  30  * This is a pretty minimalistic demo for now.  Eventually, use some
  31  * interesting cube map textures and 3D objects.
  32  * For now, we use 6 checkerboard "walls" and a sphere (good for
  33  * verification purposes).
  34  */
  35
  36
  37 #include <assert.h>
  38 #include <math.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include "GL/glut.h"
  43 #include "readtex.h"
  44
  45
  46 static GLfloat Xrot = 0, Yrot = 0;
  47 static GLfloat EyeDist = 10;
  48 static GLboolean use_vertex_arrays = GL_FALSE;
  49 static GLboolean anim = GL_TRUE;
  50 static GLboolean NoClear = GL_FALSE;
  51 static GLint FrameParity = 0;
  52
  53 #define eps1 0.99
  54 #define br   20.0  /* box radius */
  55
  56 static const GLfloat tex_coords[] = {
  57    /* +X side */
  58    1.0, -eps1, -eps1,
  59    1.0, -eps1,  eps1,
  60    1.0,  eps1,  eps1,
  61    1.0,  eps1, -eps1,
  62
  63    /* -X side */
  64    -1.0,  eps1, -eps1,
  65    -1.0,  eps1,  eps1,
  66    -1.0, -eps1,  eps1,
  67    -1.0, -eps1, -eps1,
  68
  69    /* +Y side */
  70    -eps1, 1.0, -eps1,
  71    -eps1, 1.0,  eps1,
  72     eps1, 1.0,  eps1,
  73     eps1, 1.0, -eps1,
  74
  75    /* -Y side */
  76    -eps1, -1.0, -eps1,
  77    -eps1, -1.0,  eps1,
  78     eps1, -1.0,  eps1,
  79     eps1, -1.0, -eps1,
  80
  81    /* +Z side */
  82     eps1, -eps1, 1.0,
  83    -eps1, -eps1, 1.0,
  84    -eps1,  eps1, 1.0,
  85     eps1,  eps1, 1.0,
  86
  87    /* -Z side */
  88     eps1,  eps1, -1.0,
  89    -eps1,  eps1, -1.0,
  90    -eps1, -eps1, -1.0,
  91     eps1, -eps1, -1.0,
  92 };
  93
  94 static const GLfloat vtx_coords[] = {
  95    /* +X side */
  96    br, -br, -br,
  97    br, -br,  br,
  98    br,  br,  br,
  99    br,  br, -br,
 100
 101    /* -X side */
 102    -br,  br, -br,
 103    -br,  br,  br,
 104    -br, -br,  br,
 105    -br, -br, -br,
 106
 107    /* +Y side */
 108    -br,  br, -br,
 109    -br,  br,  br,
 110     br,  br,  br,
 111     br,  br, -br,
 112
 113    /* -Y side */
 114    -br, -br, -br,
 115    -br, -br,  br,
 116     br, -br,  br,
 117     br, -br, -br,
 118
 119    /* +Z side */
 120     br, -br, br,
 121    -br, -br, br,
 122    -br,  br, br,
 123     br,  br, br,
 124
 125    /* -Z side */
 126     br,  br, -br,
 127    -br,  br, -br,
 128    -br, -br, -br,
 129     br, -br, -br,
 130 };
 131
 132 static void draw_skybox( void )
 133 {
 134    if ( use_vertex_arrays ) {
 135       glTexCoordPointer( 3, GL_FLOAT, 0, tex_coords );
 136       glVertexPointer(   3, GL_FLOAT, 0, vtx_coords );
 137
 138       glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 139       glEnableClientState( GL_VERTEX_ARRAY );
 140
 141       glDrawArrays( GL_QUADS, 0, 24 );
 142
 143       glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 144       glDisableClientState( GL_VERTEX_ARRAY );
 145    }
 146    else {
 147       unsigned   i;
 148
 149       glBegin(GL_QUADS);
 150       for ( i = 0 ; i < 24 ; i++ ) {
 151          glTexCoord3fv( & tex_coords[ i * 3 ] );
 152          glVertex3fv  ( & vtx_coords[ i * 3 ] );
 153       }
 154       glEnd();
 155    }
 156 }
 157
 158
 159 static void draw( void )
 160 {
 161    if (NoClear) {
 162       /* This demonstrates how we can avoid calling glClear.
 163        * This method only works if every pixel in the window is painted for
 164        * every frame.
 165        * We can simply skip clearing of the color buffer in this case.
 166        * For the depth buffer, we alternately use a different subrange of
 167        * the depth buffer for each frame.  For the odd frame use the range
 168        * [0, 0.5] with GL_LESS.  For the even frames, use the range [1, 0.5]
 169        * with GL_GREATER.
 170        */
 171       FrameParity = 1 - FrameParity;
 172       if (FrameParity) {
 173          glDepthRange(0.0, 0.5);
 174          glDepthFunc(GL_LESS);
 175       }
 176       else {
 177          glDepthRange(1.0, 0.5);
 178          glDepthFunc(GL_GREATER);
 179       }
 180    }
 181    else {
 182       /* ordinary clearing */
 183       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 184    }
 185
 186    glPushMatrix(); /*MODELVIEW*/
 187       glTranslatef( 0.0, 0.0, -EyeDist );
 188
 189       /* skybox */
 190       glDisable(GL_TEXTURE_GEN_S);
 191       glDisable(GL_TEXTURE_GEN_T);
 192       glDisable(GL_TEXTURE_GEN_R);
 193
 194       glMatrixMode(GL_MODELVIEW);
 195       glPushMatrix();
 196          glRotatef(Xrot, 1, 0, 0);
 197          glRotatef(Yrot, 0, 1, 0);
 198          draw_skybox();
 199       glPopMatrix();
 200
 201       /* sphere */
 202       glMatrixMode(GL_TEXTURE);
 203       glLoadIdentity();
 204       glRotatef(-Yrot, 0, 1, 0);
 205       glRotatef(-Xrot, 1, 0, 0);
 206
 207       glEnable(GL_TEXTURE_GEN_S);
 208       glEnable(GL_TEXTURE_GEN_T);
 209       glEnable(GL_TEXTURE_GEN_R);
 210       glutSolidSphere(2.0, 20, 20);
 211
 212       glLoadIdentity(); /* texture */
 213
 214       glMatrixMode(GL_MODELVIEW);
 215    glPopMatrix();
 216
 217    glutSwapBuffers();
 218 }
 219
 220
 221 static void idle(void)
 222 {
 223    GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
 224    Yrot = t;
 225    glutPostRedisplay();
 226 }
 227
 228
 229 static void set_mode(GLuint mode)
 230 {
 231    if (mode == 0) {
 232       glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 233       glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 234       glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 235       printf("GL_REFLECTION_MAP_ARB mode\n");
 236    }
 237    else if (mode == 1) {
 238       glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 239       glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 240       glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 241       printf("GL_NORMAL_MAP_ARB mode\n");
 242    }
 243 }
 244
 245
 246 static void key(unsigned char k, int x, int y)
 247 {
 248    static GLuint mode = 0;
 249    (void) x;
 250    (void) y;
 251    switch (k) {
 252       case ' ':
 253          anim = !anim;
 254          if (anim)
 255             glutIdleFunc(idle);
 256          else
 257             glutIdleFunc(NULL);
 258          break;
 259       case 'm':
 260          mode = !mode;
 261          set_mode(mode);
 262          break;
 263       case 'v':
 264          use_vertex_arrays = ! use_vertex_arrays;
 265          printf( "Vertex arrays are %sabled\n",
 266                  (use_vertex_arrays) ? "en" : "dis" );
 267          break;
 268       case 'z':
 269          EyeDist -= 0.5;
 270          if (EyeDist < 6.0)
 271             EyeDist = 6.0;
 272          break;
 273       case 'Z':
 274          EyeDist += 0.5;
 275          if (EyeDist > 90.0)
 276             EyeDist = 90;
 277          break;
 278       case 27:
 279          exit(0);
 280    }
 281    glutPostRedisplay();
 282 }
 283
 284
 285 static void specialkey(int key, int x, int y)
 286 {
 287    GLfloat step = 5;
 288    (void) x;
 289    (void) y;
 290    switch (key) {
 291       case GLUT_KEY_UP:
 292          Xrot += step;
 293          break;
 294       case GLUT_KEY_DOWN:
 295          Xrot -= step;
 296          break;
 297       case GLUT_KEY_LEFT:
 298          Yrot -= step;
 299          break;
 300       case GLUT_KEY_RIGHT:
 301          Yrot += step;
 302          break;
 303    }
 304    glutPostRedisplay();
 305 }
 306
 307
 308 /* new window size or exposure */
 309 static void reshape(int width, int height)
 310 {
 311    GLfloat ar = (float) width / (float) height;
 312    glViewport(0, 0, (GLint)width, (GLint)height);
 313    glMatrixMode(GL_PROJECTION);
 314    glLoadIdentity();
 315    glFrustum( -2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0 );
 316    glMatrixMode(GL_MODELVIEW);
 317    glLoadIdentity();
 318 }
 319
 320
 321 static void init_checkers( void )
 322 {
 323 #define CUBE_TEX_SIZE 64
 324    GLubyte image[CUBE_TEX_SIZE][CUBE_TEX_SIZE][3];
 325    static const GLubyte colors[6][3] = {
 326       { 255,   0,   0 },        /* face 0 - red */
 327       {   0, 255, 255 },        /* face 1 - cyan */
 328       {   0, 255,   0 },        /* face 2 - green */
 329       { 255,   0, 255 },        /* face 3 - purple */
 330       {   0,   0, 255 },        /* face 4 - blue */
 331       { 255, 255,   0 }         /* face 5 - yellow */
 332    };
 333    static const GLenum targets[6] = {
 334       GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 335       GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 336       GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 337       GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 338       GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 339       GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB
 340    };
 341
 342    GLint i, j, f;
 343
 344    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 345
 346    /* make colored checkerboard cube faces */
 347    for (f = 0; f < 6; f++) {
 348       for (i = 0; i < CUBE_TEX_SIZE; i++) {
 349          for (j = 0; j < CUBE_TEX_SIZE; j++) {
 350             if ((i/4 + j/4) & 1) {
 351                image[i][j][0] = colors[f][0];
 352                image[i][j][1] = colors[f][1];
 353                image[i][j][2] = colors[f][2];
 354             }
 355             else {
 356                image[i][j][0] = 255;
 357                image[i][j][1] = 255;
 358                image[i][j][2] = 255;
 359             }
 360          }
 361       }
 362
 363       glTexImage2D(targets[f], 0, GL_RGB, CUBE_TEX_SIZE, CUBE_TEX_SIZE, 0,
 364                    GL_RGB, GL_UNSIGNED_BYTE, image);
 365    }
 366 }
 367
 368
 369 static void load(GLenum target, const char *filename,
 370                  GLboolean flipTB, GLboolean flipLR)
 371 {
 372    GLint w, h;
 373    GLenum format;
 374    GLubyte *img = LoadRGBImage( filename, &w, &h, &format );
 375    if (!img) {
 376       printf("Error: couldn't load texture image %s\n", filename);
 377       exit(1);
 378    }
 379    assert(format == GL_RGB);
 380
 381    /* <sigh> the way the texture cube mapping works, we have to flip
 382     * images to make things look right.
 383     */
 384    if (flipTB) {
 385       const int stride = 3 * w;
 386       GLubyte temp[3*1024];
 387       int i;
 388       for (i = 0; i < h / 2; i++) {
 389          memcpy(temp, img + i * stride, stride);
 390          memcpy(img + i * stride, img + (h - i - 1) * stride, stride);
 391          memcpy(img + (h - i - 1) * stride, temp, stride);
 392       }
 393    }
 394    if (flipLR) {
 395       const int stride = 3 * w;
 396       GLubyte temp[3];
 397       GLubyte *row;
 398       int i, j;
 399       for (i = 0; i < h; i++) {
 400          row = img + i * stride;
 401          for (j = 0; j < w / 2; j++) {
 402             int k = w - j - 1;
 403             temp[0] = row[j*3+0];
 404             temp[1] = row[j*3+1];
 405             temp[2] = row[j*3+2];
 406             row[j*3+0] = row[k*3+0];
 407             row[j*3+1] = row[k*3+1];
 408             row[j*3+2] = row[k*3+2];
 409             row[k*3+0] = temp[0];
 410             row[k*3+1] = temp[1];
 411             row[k*3+2] = temp[2];
 412          }
 413       }
 414    }
 415
 416    gluBuild2DMipmaps(target, GL_RGB, w, h, format, GL_UNSIGNED_BYTE, img);
 417    free(img);
 418 }
 419
 420
 421 static void load_envmaps(void)
 422 {
 423    load(GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB, "right.rgb", GL_TRUE, GL_FALSE);
 424    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB, "left.rgb", GL_TRUE, GL_FALSE);
 425    load(GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB, "top.rgb", GL_FALSE, GL_TRUE);
 426    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB, "bottom.rgb", GL_FALSE, GL_TRUE);
 427    load(GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB, "front.rgb", GL_TRUE, GL_FALSE);
 428    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB, "back.rgb", GL_TRUE, GL_FALSE);
 429 }
 430
 431
 432 static void init( GLboolean useImageFiles )
 433 {
 434    GLenum filter;
 435
 436    /* check for extension */
 437    {
 438       char *exten = (char *) glGetString(GL_EXTENSIONS);
 439       if (!strstr(exten, "GL_ARB_texture_cube_map")) {
 440          printf("Sorry, this demo requires GL_ARB_texture_cube_map\n");
 441          exit(0);
 442       }
 443    }
 444    printf("GL_RENDERER: %s\n", (char *) glGetString(GL_RENDERER));
 445
 446    if (useImageFiles) {
 447       load_envmaps();
 448       filter = GL_LINEAR;
 449    }
 450    else {
 451       init_checkers();
 452       filter = GL_NEAREST;
 453    }
 454
 455    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, filter);
 456    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, filter);
 457    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 458    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 459
 460    glEnable(GL_TEXTURE_CUBE_MAP_ARB);
 461    glEnable(GL_DEPTH_TEST);
 462
 463    glClearColor(.3, .3, .3, 0);
 464    glColor3f( 1.0, 1.0, 1.0 );
 465
 466    set_mode(0);
 467 }
 468
 469
 470 static void usage(void)
 471 {
 472    printf("keys:\n");
 473    printf("  SPACE - toggle animation\n");
 474    printf("  CURSOR KEYS - rotation\n");
 475    printf("  m - toggle texgen reflection mode\n");
 476    printf("  z/Z - change viewing distance\n");
 477 }
 478
 479
 480 static void parse_args(int argc, char *argv[])
 481 {
 482    int initFlag = 0;
 483    int i;
 484
 485    for (i = 1; i < argc; i++) {
 486       if (strcmp(argv[i], "-i") == 0)
 487          initFlag = 1;
 488       else if (strcmp(argv[i], "--noclear") == 0)
 489          NoClear = GL_TRUE;
 490       else {
 491          fprintf(stderr, "Bad option: %s\n", argv[i]);
 492          exit(1);
 493       }
 494    }
 495    init (initFlag);
 496 }
 497
 498 int main( int argc, char *argv[] )
 499 {
 500    glutInit(&argc, argv);
 501    glutInitWindowPosition(0, 0);
 502    glutInitWindowSize(600, 500);
 503    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 504    glutCreateWindow("Texture Cube Mapping");
 505    glutReshapeFunc( reshape );
 506    glutKeyboardFunc( key );
 507    glutSpecialFunc( specialkey );
 508    glutDisplayFunc( draw );
 509    if (anim)
 510       glutIdleFunc(idle);
 511    parse_args(argc, argv);
 512    usage();
 513    glutMainLoop();
 514    return 0;
 515 }