progs/demos/cubemap.c

   1 /* $Id: cubemap.c,v 1.4 2002/10/25 17:20:26 brianp Exp $ */
   2
   3 /*
   4  * GL_ARB_texture_cube_map demo
   5  *
   6  * Brian Paul
   7  * May 2000
   8  *
   9  *
  10  * Copyright (C) 2000  Brian Paul   All Rights Reserved.
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a
  13  * copy of this software and associated documentation files (the "Software"),
  14  * to deal in the Software without restriction, including without limitation
  15  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  16  * and/or sell copies of the Software, and to permit persons to whom the
  17  * Software is furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included
  20  * in all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  23  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  25  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  26  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  27  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28  */
  29
  30
  31 /*
  32  * This is a pretty minimalistic demo for now.  Eventually, use some
  33  * interesting cube map textures and 3D objects.
  34  * For now, we use 6 checkerboard "walls" and a sphere (good for
  35  * verification purposes).
  36  */
  37
  38
  39 #include <assert.h>
  40 #include <math.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include "GL/glut.h"
  45 #include "../util/readtex.c" /* a hack */
  46
  47
  48 static GLfloat Xrot = 0, Yrot = 0;
  49 static GLfloat EyeDist = 10;
  50
  51
  52 static void draw_skybox( void )
  53 {
  54    const GLfloat eps1 = 0.99;
  55    const GLfloat br = 20.0; /* box radius */
  56
  57    glBegin(GL_QUADS);
  58
  59    /* +X side */
  60    glTexCoord3f(1.0, -eps1, -eps1);  glVertex3f(br, -br, -br);
  61    glTexCoord3f(1.0, -eps1,  eps1);  glVertex3f(br, -br,  br);
  62    glTexCoord3f(1.0,  eps1,  eps1);  glVertex3f(br,  br,  br);
  63    glTexCoord3f(1.0,  eps1, -eps1);  glVertex3f(br,  br, -br);
  64
  65    /* -X side */
  66    glTexCoord3f(-1.0,  eps1, -eps1);  glVertex3f(-br,  br, -br);
  67    glTexCoord3f(-1.0,  eps1,  eps1);  glVertex3f(-br,  br,  br);
  68    glTexCoord3f(-1.0, -eps1,  eps1);  glVertex3f(-br, -br,  br);
  69    glTexCoord3f(-1.0, -eps1, -eps1);  glVertex3f(-br, -br, -br);
  70
  71    /* +Y side */
  72    glTexCoord3f(-eps1, 1.0, -eps1);  glVertex3f(-br,  br, -br);
  73    glTexCoord3f(-eps1, 1.0,  eps1);  glVertex3f(-br,  br,  br);
  74    glTexCoord3f( eps1, 1.0,  eps1);  glVertex3f( br,  br,  br);
  75    glTexCoord3f( eps1, 1.0, -eps1);  glVertex3f( br,  br, -br);
  76
  77    /* -Y side */
  78    glTexCoord3f(-eps1, -1.0, -eps1);  glVertex3f(-br, -br, -br);
  79    glTexCoord3f(-eps1, -1.0,  eps1);  glVertex3f(-br, -br,  br);
  80    glTexCoord3f( eps1, -1.0,  eps1);  glVertex3f( br, -br,  br);
  81    glTexCoord3f( eps1, -1.0, -eps1);  glVertex3f( br, -br, -br);
  82
  83    /* +Z side */
  84    glTexCoord3f( eps1, -eps1, 1.0);  glVertex3f( br, -br, br);
  85    glTexCoord3f(-eps1, -eps1, 1.0);  glVertex3f(-br, -br, br);
  86    glTexCoord3f(-eps1,  eps1, 1.0);  glVertex3f(-br,  br, br);
  87    glTexCoord3f( eps1,  eps1, 1.0);  glVertex3f( br,  br, br);
  88
  89    /* -Z side */
  90    glTexCoord3f( eps1,  eps1, -1.0);  glVertex3f( br,  br, -br);
  91    glTexCoord3f(-eps1,  eps1, -1.0);  glVertex3f(-br,  br, -br);
  92    glTexCoord3f(-eps1, -eps1, -1.0);  glVertex3f(-br, -br, -br);
  93    glTexCoord3f( eps1, -eps1, -1.0);  glVertex3f( br, -br, -br);
  94
  95    glEnd();
  96 }
  97
  98
  99 static void draw( void )
 100 {
 101    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 102
 103    glPushMatrix(); /*MODELVIEW*/
 104       glTranslatef( 0.0, 0.0, -EyeDist );
 105
 106       /* skybox */
 107       glDisable(GL_TEXTURE_GEN_S);
 108       glDisable(GL_TEXTURE_GEN_T);
 109       glDisable(GL_TEXTURE_GEN_R);
 110
 111       glMatrixMode(GL_MODELVIEW);
 112       glPushMatrix();
 113          glRotatef(Xrot, 1, 0, 0);
 114          glRotatef(Yrot, 0, 1, 0);
 115          draw_skybox();
 116       glPopMatrix();
 117
 118       /* sphere */
 119       glMatrixMode(GL_TEXTURE);
 120       glLoadIdentity();
 121       glRotatef(-Yrot, 0, 1, 0);
 122       glRotatef(-Xrot, 1, 0, 0);
 123
 124       glEnable(GL_TEXTURE_GEN_S);
 125       glEnable(GL_TEXTURE_GEN_T);
 126       glEnable(GL_TEXTURE_GEN_R);
 127       glutSolidSphere(2.0, 20, 20);
 128
 129       glLoadIdentity(); /* texture */
 130
 131       glMatrixMode(GL_MODELVIEW);
 132    glPopMatrix();
 133
 134    glutSwapBuffers();
 135 }
 136
 137
 138 static void idle(void)
 139 {
 140    GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
 141    Yrot = t;
 142    glutPostRedisplay();
 143 }
 144
 145
 146 static void set_mode(GLuint mode)
 147 {
 148    if (mode == 0) {
 149       glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 150       glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 151       glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
 152       printf("GL_REFLECTION_MAP_ARB mode\n");
 153    }
 154    else if (mode == 1) {
 155       glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 156       glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 157       glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
 158       printf("GL_NORMAL_MAP_ARB mode\n");
 159    }
 160 }
 161
 162
 163 static void key(unsigned char k, int x, int y)
 164 {
 165    static GLboolean anim = GL_TRUE;
 166    static GLuint mode = 0;
 167    (void) x;
 168    (void) y;
 169    switch (k) {
 170       case ' ':
 171          anim = !anim;
 172          if (anim)
 173             glutIdleFunc(idle);
 174          else
 175             glutIdleFunc(NULL);
 176          break;
 177       case 'm':
 178          mode = !mode;
 179          set_mode(mode);
 180          break;
 181       case 'z':
 182          EyeDist -= 0.5;
 183          if (EyeDist < 6.0)
 184             EyeDist = 6.0;
 185          break;
 186       case 'Z':
 187          EyeDist += 0.5;
 188          if (EyeDist > 90.0)
 189             EyeDist = 90;
 190          break;
 191       case 27:
 192          exit(0);
 193    }
 194    glutPostRedisplay();
 195 }
 196
 197
 198 static void specialkey(int key, int x, int y)
 199 {
 200    GLfloat step = 5;
 201    (void) x;
 202    (void) y;
 203    switch (key) {
 204       case GLUT_KEY_UP:
 205          Xrot += step;
 206          break;
 207       case GLUT_KEY_DOWN:
 208          Xrot -= step;
 209          break;
 210       case GLUT_KEY_LEFT:
 211          Yrot -= step;
 212          break;
 213       case GLUT_KEY_RIGHT:
 214          Yrot += step;
 215          break;
 216    }
 217    glutPostRedisplay();
 218 }
 219
 220
 221 /* new window size or exposure */
 222 static void reshape(int width, int height)
 223 {
 224    GLfloat ar = (float) width / (float) height;
 225    glViewport(0, 0, (GLint)width, (GLint)height);
 226    glMatrixMode(GL_PROJECTION);
 227    glLoadIdentity();
 228    glFrustum( -2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0 );
 229    glMatrixMode(GL_MODELVIEW);
 230    glLoadIdentity();
 231 }
 232
 233
 234 static void init_checkers( void )
 235 {
 236 #define CUBE_TEX_SIZE 64
 237    GLubyte image[CUBE_TEX_SIZE][CUBE_TEX_SIZE][3];
 238    static const GLubyte colors[6][3] = {
 239       { 255,   0,   0 },
 240       {   0, 255, 255 },
 241       {   0, 255,   0 },
 242       { 255,   0, 255 },
 243       {   0,   0, 255 },
 244       { 255, 255,   0 }
 245    };
 246    static const GLenum targets[6] = {
 247       GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 248       GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 249       GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 250       GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 251       GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 252       GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB
 253    };
 254
 255    GLint i, j, f;
 256
 257    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 258
 259    /* make colored checkerboard cube faces */
 260    for (f = 0; f < 6; f++) {
 261       for (i = 0; i < CUBE_TEX_SIZE; i++) {
 262          for (j = 0; j < CUBE_TEX_SIZE; j++) {
 263             if ((i/4 + j/4) & 1) {
 264                image[i][j][0] = colors[f][0];
 265                image[i][j][1] = colors[f][1];
 266                image[i][j][2] = colors[f][2];
 267             }
 268             else {
 269                image[i][j][0] = 255;
 270                image[i][j][1] = 255;
 271                image[i][j][2] = 255;
 272             }
 273          }
 274       }
 275
 276       glTexImage2D(targets[f], 0, GL_RGB, CUBE_TEX_SIZE, CUBE_TEX_SIZE, 0,
 277                    GL_RGB, GL_UNSIGNED_BYTE, image);
 278    }
 279 }
 280
 281
 282 static void load(GLenum target, const char *filename,
 283                  GLboolean flipTB, GLboolean flipLR)
 284 {
 285    GLint w, h;
 286    GLenum format;
 287    GLubyte *img = LoadRGBImage( filename, &w, &h, &format );
 288    if (!img) {
 289       printf("Error: couldn't load texture image %s\n", filename);
 290       exit(1);
 291    }
 292    assert(format == GL_RGB);
 293
 294    /* <sigh> the way the texture cube mapping works, we have to flip
 295     * images to make things look right.
 296     */
 297    if (flipTB) {
 298       const int stride = 3 * w;
 299       GLubyte temp[3*1024];
 300       int i;
 301       for (i = 0; i < h / 2; i++) {
 302          memcpy(temp, img + i * stride, stride);
 303          memcpy(img + i * stride, img + (h - i - 1) * stride, stride);
 304          memcpy(img + (h - i - 1) * stride, temp, stride);
 305       }
 306    }
 307    if (flipLR) {
 308       const int stride = 3 * w;
 309       GLubyte temp[3];
 310       GLubyte *row;
 311       int i, j;
 312       for (i = 0; i < h; i++) {
 313          row = img + i * stride;
 314          for (j = 0; j < w / 2; j++) {
 315             int k = w - j - 1;
 316             temp[0] = row[j*3+0];
 317             temp[1] = row[j*3+1];
 318             temp[2] = row[j*3+2];
 319             row[j*3+0] = row[k*3+0];
 320             row[j*3+1] = row[k*3+1];
 321             row[j*3+2] = row[k*3+2];
 322             row[k*3+0] = temp[0];
 323             row[k*3+1] = temp[1];
 324             row[k*3+2] = temp[2];
 325          }
 326       }
 327    }
 328
 329    gluBuild2DMipmaps(target, GL_RGB, w, h, format, GL_UNSIGNED_BYTE, img);
 330    free(img);
 331 }
 332
 333
 334 static void load_envmaps(void)
 335 {
 336    load(GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB, "right.rgb", GL_TRUE, GL_FALSE);
 337    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB, "left.rgb", GL_TRUE, GL_FALSE);
 338    load(GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB, "top.rgb", GL_FALSE, GL_TRUE);
 339    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB, "bottom.rgb", GL_FALSE, GL_TRUE);
 340    load(GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB, "front.rgb", GL_TRUE, GL_FALSE);
 341    load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB, "back.rgb", GL_TRUE, GL_FALSE);
 342 }
 343
 344
 345 static void init( GLboolean useImageFiles )
 346 {
 347    GLenum filter;
 348
 349    /* check for extension */
 350    {
 351       char *exten = (char *) glGetString(GL_EXTENSIONS);
 352       if (!strstr(exten, "GL_ARB_texture_cube_map")) {
 353          printf("Sorry, this demo requires GL_ARB_texture_cube_map\n");
 354          exit(0);
 355       }
 356    }
 357    printf("GL_RENDERER: %s\n", (char *) glGetString(GL_RENDERER));
 358
 359    if (useImageFiles) {
 360       load_envmaps();
 361       filter = GL_LINEAR;
 362    }
 363    else {
 364       init_checkers();
 365       filter = GL_NEAREST;
 366    }
 367
 368    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, filter);
 369    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, filter);
 370    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 371    glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 372
 373    glEnable(GL_TEXTURE_CUBE_MAP_ARB);
 374    glEnable(GL_DEPTH_TEST);
 375
 376    glClearColor(.3, .3, .3, 0);
 377    glColor3f( 1.0, 1.0, 1.0 );
 378
 379    set_mode(0);
 380 }
 381
 382
 383 static void usage(void)
 384 {
 385    printf("keys:\n");
 386    printf("  SPACE - toggle animation\n");
 387    printf("  CURSOR KEYS - rotation\n");
 388    printf("  m - toggle texgen reflection mode\n");
 389    printf("  z/Z - change viewing distance\n");
 390 }
 391
 392
 393 int main( int argc, char *argv[] )
 394 {
 395    glutInitWindowPosition(0, 0);
 396    glutInitWindowSize(600, 500);
 397    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 398    glutCreateWindow("Texture Cube Maping");
 399
 400    if (argc > 1 && strcmp(argv[1] , "-i") == 0)
 401       init( 1 );
 402    else
 403       init( 0 );
 404    glutReshapeFunc( reshape );
 405    glutKeyboardFunc( key );
 406    glutSpecialFunc( specialkey );
 407    glutIdleFunc( idle );
 408    glutDisplayFunc( draw );
 409    usage();
 410    glutMainLoop();
 411    return 0;
 412 }