progs/tests/fbotexture.c

   1 /*
   2  * Test GL_EXT_framebuffer_object render-to-texture
   3  *
   4  * Draw a teapot into a texture image with stenciling.
   5  * Then draw a textured quad using that texture.
   6  *
   7  * Brian Paul
   8  * 18 Apr 2005
   9  */
  10
  11
  12 #define GL_GLEXT_PROTOTYPES
  13 #include <GL/glut.h>
  14 #include <assert.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <math.h>
  19
  20 /* For debug */
  21 #define DEPTH 1
  22 #define STENCIL 1
  23 #define DRAW 1
  24
  25
  26 static int Win = 0;
  27 static int Width = 400, Height = 400;
  28
  29 static GLenum TexTarget = GL_TEXTURE_2D; /*GL_TEXTURE_RECTANGLE_ARB;*/
  30 static int TexWidth = 512, TexHeight = 512;
  31 /*static int TexWidth = 600, TexHeight = 600;*/
  32
  33 static GLuint MyFB;
  34 static GLuint TexObj;
  35 static GLuint DepthRB, StencilRB;
  36 static GLboolean Anim = GL_FALSE;
  37 static GLfloat Rot = 0.0;
  38 static GLboolean UsePackedDepthStencil = GL_FALSE;
  39 static GLuint TextureLevel = 1;  /* which texture level to render to */
  40 static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */
  41 static GLboolean Cull = GL_FALSE;
  42 static GLboolean Wireframe = GL_FALSE;
  43
  44
  45 static void
  46 CheckError(int line)
  47 {
  48    GLenum err = glGetError();
  49    if (err) {
  50       printf("GL Error 0x%x at line %d\n", (int) err, line);
  51    }
  52 }
  53
  54
  55 static void
  56 Idle(void)
  57 {
  58    Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
  59    glutPostRedisplay();
  60 }
  61
  62
  63 static void
  64 RenderTexture(void)
  65 {
  66    GLenum status;
  67
  68    glMatrixMode(GL_PROJECTION);
  69    glLoadIdentity();
  70    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  71    glMatrixMode(GL_MODELVIEW);
  72    glLoadIdentity();
  73    glTranslatef(0.0, 0.0, -15.0);
  74
  75    /* draw to texture image */
  76    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
  77
  78    status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
  79    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
  80       printf("Framebuffer incomplete!!!\n");
  81    }
  82
  83    glViewport(0, 0, TexWidth, TexHeight);
  84
  85    glClearColor(0.5, 0.5, 1.0, 0.0);
  86    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
  87    CheckError(__LINE__);
  88
  89 #if DEPTH
  90    glEnable(GL_DEPTH_TEST);
  91 #endif
  92
  93 #if STENCIL
  94    glEnable(GL_STENCIL_TEST);
  95    glStencilFunc(GL_NEVER, 1, ~0);
  96    glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE);
  97 #endif
  98
  99    CheckError(__LINE__);
 100
 101 #if DEPTH || STENCIL
 102    /* draw diamond-shaped stencil pattern */
 103    glColor3f(0, 1, 0);
 104    glBegin(GL_POLYGON);
 105    glVertex2f(-0.2,  0.0);
 106    glVertex2f( 0.0, -0.2);
 107    glVertex2f( 0.2,  0.0);
 108    glVertex2f( 0.0,  0.2);
 109    glEnd();
 110 #endif
 111
 112    /* draw teapot where stencil != 1 */
 113 #if STENCIL
 114    glStencilFunc(GL_NOTEQUAL, 1, ~0);
 115    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 116 #endif
 117
 118    CheckError(__LINE__);
 119
 120    if (Wireframe) {
 121       glPolygonMode(GL_FRONT, GL_LINE);
 122    }
 123    else {
 124       glPolygonMode(GL_FRONT, GL_FILL);
 125    }
 126
 127    if (Cull) {
 128       /* cull back */
 129       glCullFace(GL_BACK);
 130       glEnable(GL_CULL_FACE);
 131    }
 132    else {
 133       glDisable(GL_CULL_FACE);
 134    }
 135
 136 #if 0
 137    glBegin(GL_POLYGON);
 138    glColor3f(1, 0, 0);
 139    glVertex2f(-1, -1);
 140    glColor3f(0, 1, 0);
 141    glVertex2f(1, -1);
 142    glColor3f(0, 0, 1);
 143    glVertex2f(0, 1);
 144    glEnd();
 145 #else
 146    glEnable(GL_LIGHTING);
 147    glEnable(GL_LIGHT0);
 148    glPushMatrix();
 149    glRotatef(0.5 * Rot, 1.0, 0.0, 0.0);
 150    glFrontFace(GL_CW); /* Teapot patches backward */
 151    glutSolidTeapot(0.5);
 152    glFrontFace(GL_CCW);
 153    glPopMatrix();
 154    glDisable(GL_LIGHTING);
 155    /*
 156    PrintStencilHistogram(TexWidth, TexHeight);
 157    */
 158 #endif
 159
 160    glDisable(GL_DEPTH_TEST);
 161    glDisable(GL_STENCIL_TEST);
 162    glDisable(GL_CULL_FACE);
 163    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 164
 165 #if DRAW
 166    /* Bind normal framebuffer */
 167    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
 168 #endif
 169
 170    CheckError(__LINE__);
 171 }
 172
 173
 174
 175 static void
 176 Display(void)
 177 {
 178    float ar = (float) Width / (float) Height;
 179
 180    RenderTexture();
 181
 182    /* draw textured quad in the window */
 183 #if DRAW
 184    glMatrixMode(GL_PROJECTION);
 185    glLoadIdentity();
 186    glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
 187    glMatrixMode(GL_MODELVIEW);
 188    glLoadIdentity();
 189    glTranslatef(0.0, 0.0, -7.0);
 190
 191    glViewport(0, 0, Width, Height);
 192
 193    glClearColor(0.25, 0.25, 0.25, 0);
 194    glClear(GL_COLOR_BUFFER_BIT);
 195
 196    glPushMatrix();
 197    glRotatef(Rot, 0, 1, 0);
 198    glEnable(TexTarget);
 199    glBindTexture(TexTarget, TexObj);
 200    glBegin(GL_POLYGON);
 201    glColor3f(0.25, 0.25, 0.25);
 202    if (TexTarget == GL_TEXTURE_2D) {
 203       glTexCoord2f(0, 0);
 204       glVertex2f(-1, -1);
 205       glTexCoord2f(1, 0);
 206       glVertex2f(1, -1);
 207       glColor3f(1.0, 1.0, 1.0);
 208       glTexCoord2f(1, 1);
 209       glVertex2f(1, 1);
 210       glTexCoord2f(0, 1);
 211       glVertex2f(-1, 1);
 212    }
 213    else {
 214       assert(TexTarget == GL_TEXTURE_RECTANGLE_ARB);
 215       glTexCoord2f(0, 0);
 216       glVertex2f(-1, -1);
 217       glTexCoord2f(TexWidth, 0);
 218       glVertex2f(1, -1);
 219       glColor3f(1.0, 1.0, 1.0);
 220       glTexCoord2f(TexWidth, TexHeight);
 221       glVertex2f(1, 1);
 222       glTexCoord2f(0, TexHeight);
 223       glVertex2f(-1, 1);
 224    }
 225    glEnd();
 226    glPopMatrix();
 227    glDisable(TexTarget);
 228 #endif
 229
 230    glutSwapBuffers();
 231    CheckError(__LINE__);
 232 }
 233
 234
 235 static void
 236 Reshape(int width, int height)
 237 {
 238    glViewport(0, 0, width, height);
 239    Width = width;
 240    Height = height;
 241 }
 242
 243
 244 static void
 245 CleanUp(void)
 246 {
 247 #if DEPTH
 248    glDeleteRenderbuffersEXT(1, &DepthRB);
 249 #endif
 250 #if STENCIL
 251    if (!UsePackedDepthStencil)
 252       glDeleteRenderbuffersEXT(1, &StencilRB);
 253 #endif
 254    glDeleteFramebuffersEXT(1, &MyFB);
 255
 256    glDeleteTextures(1, &TexObj);
 257
 258    glutDestroyWindow(Win);
 259
 260    exit(0);
 261 }
 262
 263
 264 static void
 265 Key(unsigned char key, int x, int y)
 266 {
 267    (void) x;
 268    (void) y;
 269    switch (key) {
 270    case 'a':
 271       Anim = !Anim;
 272       if (Anim)
 273          glutIdleFunc(Idle);
 274       else
 275          glutIdleFunc(NULL);
 276       break;
 277    case 'c':
 278       Cull = !Cull;
 279       break;
 280    case 'w':
 281       Wireframe = !Wireframe;
 282       break;
 283    case 's':
 284       Rot += 2.0;
 285       break;
 286    case 'S':
 287       Rot -= 2.0;
 288       break;
 289    case 27:
 290       CleanUp();
 291       break;
 292    }
 293    glutPostRedisplay();
 294 }
 295
 296
 297 static void
 298 Usage(void)
 299 {
 300    printf("Usage:\n");
 301    printf("  a    Toggle animation\n");
 302    printf("  s/s  Step/rotate\n");
 303    printf("  c    Toggle back-face culling\n");
 304    printf("  w    Toggle wireframe mode (front-face only)\n");
 305    printf("  Esc  Exit\n");
 306 }
 307
 308
 309 static void
 310 Init(int argc, char *argv[])
 311 {
 312    static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 };
 313    GLint i;
 314
 315    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 316       printf("GL_EXT_framebuffer_object not found!\n");
 317       exit(0);
 318    }
 319
 320    if (argc > 1 && strcmp(argv[1], "-ds") == 0) {
 321       if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
 322          printf("GL_EXT_packed_depth_stencil not found!\n");
 323          exit(0);
 324       }
 325       UsePackedDepthStencil = GL_TRUE;
 326       printf("Using GL_EXT_packed_depth_stencil\n");
 327    }
 328
 329    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 330
 331    /* gen framebuffer id, delete it, do some assertions, just for testing */
 332    glGenFramebuffersEXT(1, &MyFB);
 333    assert(MyFB);
 334    assert(!glIsFramebufferEXT(MyFB));
 335    glDeleteFramebuffersEXT(1, &MyFB);
 336    assert(!glIsFramebufferEXT(MyFB));
 337    /* Note, continue to use MyFB below */
 338
 339    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
 340    assert(glIsFramebufferEXT(MyFB));
 341    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
 342    assert(i == MyFB);
 343
 344    /* Make texture object/image */
 345    glGenTextures(1, &TexObj);
 346    glBindTexture(TexTarget, TexObj);
 347    /* make two image levels */
 348    glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0,
 349                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 350    glTexImage2D(TexTarget, 1, TexIntFormat, TexWidth/2, TexHeight/2, 0,
 351                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 352    TexWidth = TexWidth >> TextureLevel;
 353    TexHeight = TexHeight >> TextureLevel;
 354
 355    glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 356    glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 357    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 358    glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel);
 359    glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel);
 360
 361    CheckError(__LINE__);
 362
 363    /* Render color to texture */
 364    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
 365                              TexTarget, TexObj, TextureLevel);
 366
 367
 368 #if DEPTH
 369    /* make depth renderbuffer */
 370    glGenRenderbuffersEXT(1, &DepthRB);
 371    assert(DepthRB);
 372    assert(!glIsRenderbufferEXT(DepthRB));
 373    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRB);
 374    assert(glIsRenderbufferEXT(DepthRB));
 375    if (UsePackedDepthStencil)
 376       glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_STENCIL_EXT,
 377                                TexWidth, TexHeight);
 378    else
 379       glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
 380                                TexWidth, TexHeight);
 381    CheckError(__LINE__);
 382    glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 383                                    GL_RENDERBUFFER_DEPTH_SIZE_EXT, &i);
 384    CheckError(__LINE__);
 385    printf("Depth renderbuffer size = %d bits\n", i);
 386    assert(i > 0);
 387
 388    /* attach DepthRB to MyFB */
 389    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
 390                                 GL_RENDERBUFFER_EXT, DepthRB);
 391 #endif
 392
 393    CheckError(__LINE__);
 394
 395 #if STENCIL
 396    if (UsePackedDepthStencil) {
 397       /* DepthRb is a combined depth/stencil renderbuffer */
 398       glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
 399                                    GL_STENCIL_ATTACHMENT_EXT,
 400                                    GL_RENDERBUFFER_EXT, DepthRB);
 401    }
 402    else {
 403       /* make stencil renderbuffer */
 404       glGenRenderbuffersEXT(1, &StencilRB);
 405       assert(StencilRB);
 406       assert(!glIsRenderbufferEXT(StencilRB));
 407       glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, StencilRB);
 408       assert(glIsRenderbufferEXT(StencilRB));
 409       glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX,
 410                                TexWidth, TexHeight);
 411       /* attach StencilRB to MyFB */
 412       glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
 413                                    GL_STENCIL_ATTACHMENT_EXT,
 414                                    GL_RENDERBUFFER_EXT, StencilRB);
 415    }
 416    glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 417                                    GL_RENDERBUFFER_STENCIL_SIZE_EXT, &i);
 418    CheckError(__LINE__);
 419    printf("Stencil renderbuffer size = %d bits\n", i);
 420    assert(i > 0);
 421 #endif
 422
 423    CheckError(__LINE__);
 424
 425    /* bind regular framebuffer */
 426    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
 427
 428
 429    /* lighting */
 430    glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
 431 }
 432
 433
 434 int
 435 main(int argc, char *argv[])
 436 {
 437    glutInit(&argc, argv);
 438    glutInitWindowPosition(0, 0);
 439    glutInitWindowSize(Width, Height);
 440    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 441    Win = glutCreateWindow(argv[0]);
 442    glutReshapeFunc(Reshape);
 443    glutKeyboardFunc(Key);
 444    glutDisplayFunc(Display);
 445    if (Anim)
 446       glutIdleFunc(Idle);
 447    Init(argc, argv);
 448    Usage();
 449    glutMainLoop();
 450    return 0;
 451 }