src/demos/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 #include <assert.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <GL/glew.h>
  17 #include "glut_wrap.h"
  18
  19 /* For debug */
  20 #define DEPTH 1
  21 #define STENCIL 1
  22 #define DRAW 1
  23
  24
  25 static PFNGLISRENDERBUFFERPROC glIsRenderbuffer_func = NULL;
  26 static PFNGLBINDRENDERBUFFERPROC glBindRenderbuffer_func = NULL;
  27 static PFNGLDELETERENDERBUFFERSPROC glDeleteRenderbuffers_func = NULL;
  28 static PFNGLGENRENDERBUFFERSPROC glGenRenderbuffers_func = NULL;
  29 static PFNGLRENDERBUFFERSTORAGEPROC glRenderbufferStorage_func = NULL;
  30 static PFNGLGETRENDERBUFFERPARAMETERIVPROC glGetRenderbufferParameteriv_func = NULL;
  31 static PFNGLISFRAMEBUFFERPROC glIsFramebuffer_func = NULL;
  32 static PFNGLBINDFRAMEBUFFERPROC glBindFramebuffer_func = NULL;
  33 static PFNGLDELETEFRAMEBUFFERSPROC glDeleteFramebuffers_func = NULL;
  34 static PFNGLGENFRAMEBUFFERSPROC glGenFramebuffers_func = NULL;
  35 static PFNGLCHECKFRAMEBUFFERSTATUSPROC glCheckFramebufferStatus_func = NULL;
  36 static PFNGLFRAMEBUFFERTEXTURE1DPROC glFramebufferTexture1D_func = NULL;
  37 static PFNGLFRAMEBUFFERTEXTURE2DPROC glFramebufferTexture2D_func = NULL;
  38 static PFNGLFRAMEBUFFERTEXTURE3DPROC glFramebufferTexture3D_func = NULL;
  39 static PFNGLFRAMEBUFFERRENDERBUFFERPROC glFramebufferRenderbuffer_func = NULL;
  40 static PFNGLGETFRAMEBUFFERATTACHMENTPARAMETERIVPROC glGetFramebufferAttachmentParameteriv_func = NULL;
  41 static PFNGLGENERATEMIPMAPPROC glGenerateMipmap_func = NULL;
  42
  43
  44 static int Win = 0;
  45 static int Width = 400, Height = 400;
  46
  47 #if 1
  48 static GLenum TexTarget = GL_TEXTURE_2D;
  49 static int TexWidth = 512, TexHeight = 512;
  50 static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */
  51 #else
  52 static GLenum TexTarget = GL_TEXTURE_RECTANGLE_ARB;
  53 static int TexWidth = 200, TexHeight = 200;
  54 static GLenum TexIntFormat = GL_RGB5; /* either GL_RGB or GL_RGBA */
  55 #endif
  56 static GLuint TextureLevel = 0;  /* which texture level to render to */
  57
  58 static GLuint MyFB;
  59 static GLuint TexObj;
  60 static GLuint DepthRB = 0, StencilRB = 0;
  61 static GLboolean Anim = GL_FALSE;
  62 static GLfloat Rot = 0.0;
  63 static GLboolean UsePackedDepthStencil = GL_FALSE;
  64 static GLboolean UsePackedDepthStencilBoth = GL_FALSE;
  65 static GLboolean Use_ARB_fbo = GL_FALSE;
  66 static GLboolean Cull = GL_FALSE;
  67 static GLboolean Wireframe = GL_FALSE;
  68
  69
  70 static void
  71 CheckError(int line)
  72 {
  73    GLenum err = glGetError();
  74    if (err) {
  75       printf("GL Error 0x%x at line %d\n", (int) err, line);
  76    }
  77 }
  78
  79
  80 static void
  81 Idle(void)
  82 {
  83    Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
  84    glutPostRedisplay();
  85 }
  86
  87
  88 static void
  89 RenderTexture(void)
  90 {
  91    GLenum status;
  92
  93    glMatrixMode(GL_PROJECTION);
  94    glLoadIdentity();
  95    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  96    glMatrixMode(GL_MODELVIEW);
  97    glLoadIdentity();
  98    glTranslatef(0.0, 0.0, -15.0);
  99
 100    /* draw to texture image */
 101    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, MyFB);
 102
 103    status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 104    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 105       printf("Framebuffer incomplete!!!\n");
 106    }
 107
 108    glViewport(0, 0, TexWidth, TexHeight);
 109
 110    glClearColor(0.5, 0.5, 1.0, 0.0);
 111    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 112    CheckError(__LINE__);
 113
 114 #if DEPTH
 115    glEnable(GL_DEPTH_TEST);
 116 #endif
 117
 118 #if STENCIL
 119    glEnable(GL_STENCIL_TEST);
 120    glStencilFunc(GL_NEVER, 1, ~0);
 121    glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE);
 122 #endif
 123
 124    CheckError(__LINE__);
 125
 126 #if DEPTH || STENCIL
 127    /* draw diamond-shaped stencil pattern */
 128    glColor3f(0, 1, 0);
 129    glBegin(GL_POLYGON);
 130    glVertex2f(-0.2,  0.0);
 131    glVertex2f( 0.0, -0.2);
 132    glVertex2f( 0.2,  0.0);
 133    glVertex2f( 0.0,  0.2);
 134    glEnd();
 135 #endif
 136
 137    /* draw teapot where stencil != 1 */
 138 #if STENCIL
 139    glStencilFunc(GL_NOTEQUAL, 1, ~0);
 140    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 141 #endif
 142
 143    CheckError(__LINE__);
 144
 145    if (Wireframe) {
 146       glPolygonMode(GL_FRONT, GL_LINE);
 147    }
 148    else {
 149       glPolygonMode(GL_FRONT, GL_FILL);
 150    }
 151
 152    if (Cull) {
 153       /* cull back */
 154       glCullFace(GL_BACK);
 155       glEnable(GL_CULL_FACE);
 156    }
 157    else {
 158       glDisable(GL_CULL_FACE);
 159    }
 160
 161 #if 0
 162    glBegin(GL_POLYGON);
 163    glColor3f(1, 0, 0);
 164    glVertex2f(-1, -1);
 165    glColor3f(0, 1, 0);
 166    glVertex2f(1, -1);
 167    glColor3f(0, 0, 1);
 168    glVertex2f(0, 1);
 169    glEnd();
 170 #else
 171    glEnable(GL_LIGHTING);
 172    glEnable(GL_LIGHT0);
 173    glPushMatrix();
 174    glRotatef(0.5 * Rot, 1.0, 0.0, 0.0);
 175    glFrontFace(GL_CW); /* Teapot patches backward */
 176    glutSolidTeapot(0.5);
 177    glFrontFace(GL_CCW);
 178    glPopMatrix();
 179    glDisable(GL_LIGHTING);
 180    /*
 181    PrintStencilHistogram(TexWidth, TexHeight);
 182    */
 183 #endif
 184
 185    glDisable(GL_DEPTH_TEST);
 186    glDisable(GL_STENCIL_TEST);
 187    glDisable(GL_CULL_FACE);
 188    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 189
 190 #if DRAW
 191    /* Bind normal framebuffer */
 192    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 193 #endif
 194
 195    CheckError(__LINE__);
 196 }
 197
 198
 199
 200 static void
 201 Display(void)
 202 {
 203    float ar = (float) Width / (float) Height;
 204
 205    RenderTexture();
 206
 207    /* draw textured quad in the window */
 208 #if DRAW
 209    glMatrixMode(GL_PROJECTION);
 210    glLoadIdentity();
 211    glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
 212    glMatrixMode(GL_MODELVIEW);
 213    glLoadIdentity();
 214    glTranslatef(0.0, 0.0, -7.0);
 215
 216    glViewport(0, 0, Width, Height);
 217
 218    glClearColor(0.25, 0.25, 0.25, 0);
 219    glClear(GL_COLOR_BUFFER_BIT);
 220
 221    glPushMatrix();
 222    glRotatef(Rot, 0, 1, 0);
 223    glEnable(TexTarget);
 224    glBindTexture(TexTarget, TexObj);
 225    glBegin(GL_POLYGON);
 226    glColor3f(0.25, 0.25, 0.25);
 227    if (TexTarget == GL_TEXTURE_2D) {
 228       glTexCoord2f(0, 0);
 229       glVertex2f(-1, -1);
 230       glTexCoord2f(1, 0);
 231       glVertex2f(1, -1);
 232       glColor3f(1.0, 1.0, 1.0);
 233       glTexCoord2f(1, 1);
 234       glVertex2f(1, 1);
 235       glTexCoord2f(0, 1);
 236       glVertex2f(-1, 1);
 237    }
 238    else {
 239       assert(TexTarget == GL_TEXTURE_RECTANGLE_ARB);
 240       glTexCoord2f(0, 0);
 241       glVertex2f(-1, -1);
 242       glTexCoord2f(TexWidth, 0);
 243       glVertex2f(1, -1);
 244       glColor3f(1.0, 1.0, 1.0);
 245       glTexCoord2f(TexWidth, TexHeight);
 246       glVertex2f(1, 1);
 247       glTexCoord2f(0, TexHeight);
 248       glVertex2f(-1, 1);
 249    }
 250    glEnd();
 251    glPopMatrix();
 252    glDisable(TexTarget);
 253 #endif
 254
 255    glutSwapBuffers();
 256    CheckError(__LINE__);
 257 }
 258
 259
 260 static void
 261 Reshape(int width, int height)
 262 {
 263    glViewport(0, 0, width, height);
 264    Width = width;
 265    Height = height;
 266 }
 267
 268
 269 static void
 270 CleanUp(void)
 271 {
 272 #if DEPTH
 273    glDeleteRenderbuffers_func(1, &DepthRB);
 274 #endif
 275 #if STENCIL
 276    glDeleteRenderbuffers_func(1, &StencilRB);
 277 #endif
 278    glDeleteFramebuffers_func(1, &MyFB);
 279
 280    glDeleteTextures(1, &TexObj);
 281
 282    glutDestroyWindow(Win);
 283
 284    exit(0);
 285 }
 286
 287
 288 static void
 289 Key(unsigned char key, int x, int y)
 290 {
 291    (void) x;
 292    (void) y;
 293    switch (key) {
 294    case 'a':
 295       Anim = !Anim;
 296       if (Anim)
 297          glutIdleFunc(Idle);
 298       else
 299          glutIdleFunc(NULL);
 300       break;
 301    case 'c':
 302       Cull = !Cull;
 303       break;
 304    case 'w':
 305       Wireframe = !Wireframe;
 306       break;
 307    case 's':
 308       Rot += 2.0;
 309       break;
 310    case 'S':
 311       Rot -= 2.0;
 312       break;
 313    case 27:
 314       CleanUp();
 315       break;
 316    }
 317    glutPostRedisplay();
 318 }
 319
 320
 321 /**
 322  * Attach depth and stencil renderbuffer(s) to the given framebuffer object.
 323  * \param tryDepthStencil  if true, try to use a combined depth+stencil buffer
 324  * \param bindDepthStencil  if true, and tryDepthStencil is true, bind with
 325  *                          the GL_DEPTH_STENCIL_ATTACHMENT target.
 326  * \return GL_TRUE for success, GL_FALSE for failure
 327  */
 328 static GLboolean
 329 AttachDepthAndStencilBuffers(GLuint fbo,
 330                              GLsizei width, GLsizei height,
 331                              GLboolean tryDepthStencil,
 332                              GLboolean bindDepthStencil,
 333                              GLuint *depthRbOut, GLuint *stencilRbOut)
 334 {
 335    GLenum status;
 336
 337    *depthRbOut = *stencilRbOut = 0;
 338
 339    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fbo);
 340
 341    if (tryDepthStencil) {
 342       GLuint rb;
 343
 344       glGenRenderbuffers_func(1, &rb);
 345       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 346       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 347                                GL_DEPTH24_STENCIL8_EXT,
 348                                width, height);
 349       if (glGetError())
 350          return GL_FALSE;
 351
 352       if (bindDepthStencil) {
 353          /* attach to both depth and stencil at once */
 354          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 355                                       GL_DEPTH_STENCIL_ATTACHMENT,
 356                                       GL_RENDERBUFFER_EXT, rb);
 357          if (glGetError())
 358             return GL_FALSE;
 359       }
 360       else {
 361          /* attach to depth attachment point */
 362          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 363                                       GL_DEPTH_ATTACHMENT_EXT,
 364                                       GL_RENDERBUFFER_EXT, rb);
 365          if (glGetError())
 366             return GL_FALSE;
 367
 368          /* and attach to stencil attachment point */
 369          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 370                                       GL_STENCIL_ATTACHMENT_EXT,
 371                                       GL_RENDERBUFFER_EXT, rb);
 372          if (glGetError())
 373             return GL_FALSE;
 374       }
 375
 376       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 377       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
 378          return GL_FALSE;
 379
 380       *depthRbOut = *stencilRbOut = rb;
 381       return GL_TRUE;
 382    }
 383
 384    /* just depth renderbuffer */
 385    {
 386       GLuint rb;
 387
 388       glGenRenderbuffers_func(1, &rb);
 389       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 390       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 391                                GL_DEPTH_COMPONENT,
 392                                width, height);
 393       if (glGetError())
 394          return GL_FALSE;
 395
 396       /* attach to depth attachment point */
 397       glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 398                                    GL_DEPTH_ATTACHMENT_EXT,
 399                                    GL_RENDERBUFFER_EXT, rb);
 400       if (glGetError())
 401          return GL_FALSE;
 402
 403       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 404       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
 405          return GL_FALSE;
 406
 407       *depthRbOut = rb;
 408    }
 409
 410    /* just stencil renderbuffer */
 411    {
 412       GLuint rb;
 413
 414       glGenRenderbuffers_func(1, &rb);
 415       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 416       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 417                                GL_STENCIL_INDEX,
 418                                width, height);
 419       if (glGetError())
 420          return GL_FALSE;
 421
 422       /* attach to depth attachment point */
 423       glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 424                                    GL_STENCIL_ATTACHMENT_EXT,
 425                                    GL_RENDERBUFFER_EXT, rb);
 426       if (glGetError())
 427          return GL_FALSE;
 428
 429       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 430       if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 431          glDeleteRenderbuffers_func(1, depthRbOut);
 432          *depthRbOut = 0;
 433          glDeleteRenderbuffers_func(1, &rb);
 434          return GL_FALSE;
 435       }
 436
 437       *stencilRbOut = rb;
 438    }
 439
 440    return GL_TRUE;
 441 }
 442
 443
 444 static void
 445 ParseArgs(int argc, char *argv[])
 446 {
 447    GLint i;
 448    for (i = 1; i < argc; i++) {
 449       if (strcmp(argv[i], "-ds") == 0) {
 450          if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
 451             printf("GL_EXT_packed_depth_stencil not found!\n");
 452             exit(0);
 453          }
 454          UsePackedDepthStencil = GL_TRUE;
 455          printf("Using GL_EXT_packed_depth_stencil\n");
 456       }
 457       else if (strcmp(argv[i], "-ds2") == 0) {
 458          if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
 459             printf("GL_EXT_packed_depth_stencil not found!\n");
 460             exit(0);
 461          }
 462          if (!glutExtensionSupported("GL_ARB_framebuffer_object")) {
 463             printf("GL_ARB_framebuffer_object not found!\n");
 464             exit(0);
 465          }
 466          UsePackedDepthStencil = GL_TRUE;
 467          UsePackedDepthStencilBoth = GL_TRUE;
 468          printf("Using GL_EXT_packed_depth_stencil and GL_DEPTH_STENCIL attachment point\n");
 469       }
 470       else if (strcmp(argv[i], "-arb") == 0) {
 471          if (!glutExtensionSupported("GL_ARB_framebuffer_object")) {
 472             printf("Sorry, GL_ARB_framebuffer object not supported!\n");
 473          }
 474          else {
 475             Use_ARB_fbo = GL_TRUE;
 476          }
 477       }
 478       else {
 479          printf("Unknown option: %s\n", argv[i]);
 480       }
 481    }
 482 }
 483
 484
 485 static void
 486 SetupFunctionPointers(void)
 487 {
 488    if (Use_ARB_fbo) {
 489       /* use the ARB functions */
 490       glIsRenderbuffer_func = glIsRenderbuffer;
 491       glBindRenderbuffer_func = glBindRenderbuffer;
 492       glDeleteRenderbuffers_func = glDeleteRenderbuffers;
 493       glGenRenderbuffers_func = glGenRenderbuffers;
 494       glRenderbufferStorage_func = glRenderbufferStorage;
 495       glGetRenderbufferParameteriv_func = glGetRenderbufferParameteriv;
 496       glIsFramebuffer_func = glIsFramebuffer;
 497       glBindFramebuffer_func = glBindFramebuffer;
 498       glDeleteFramebuffers_func = glDeleteFramebuffers;
 499       glGenFramebuffers_func = glGenFramebuffers;
 500       glCheckFramebufferStatus_func = glCheckFramebufferStatus;
 501       glFramebufferTexture1D_func = glFramebufferTexture1D;
 502       glFramebufferTexture2D_func = glFramebufferTexture2D;
 503       glFramebufferTexture3D_func = glFramebufferTexture3D;
 504       glFramebufferRenderbuffer_func = glFramebufferRenderbuffer;
 505       glGetFramebufferAttachmentParameteriv_func = glGetFramebufferAttachmentParameteriv;
 506       glGenerateMipmap_func = glGenerateMipmap;
 507    }
 508    else {
 509       /* use the EXT functions */
 510       glIsRenderbuffer_func = glIsRenderbufferEXT;
 511       glBindRenderbuffer_func = glBindRenderbufferEXT;
 512       glDeleteRenderbuffers_func = glDeleteRenderbuffersEXT;
 513       glGenRenderbuffers_func = glGenRenderbuffersEXT;
 514       glRenderbufferStorage_func = glRenderbufferStorageEXT;
 515       glGetRenderbufferParameteriv_func = glGetRenderbufferParameterivEXT;
 516       glIsFramebuffer_func = glIsFramebufferEXT;
 517       glBindFramebuffer_func = glBindFramebufferEXT;
 518       glDeleteFramebuffers_func = glDeleteFramebuffersEXT;
 519       glGenFramebuffers_func = glGenFramebuffersEXT;
 520       glCheckFramebufferStatus_func = glCheckFramebufferStatusEXT;
 521       glFramebufferTexture1D_func = glFramebufferTexture1DEXT;
 522       glFramebufferTexture2D_func = glFramebufferTexture2DEXT;
 523       glFramebufferTexture3D_func = glFramebufferTexture3DEXT;
 524       glFramebufferRenderbuffer_func = glFramebufferRenderbufferEXT;
 525       glGetFramebufferAttachmentParameteriv_func = glGetFramebufferAttachmentParameterivEXT;
 526       glGenerateMipmap_func = glGenerateMipmapEXT;
 527    }
 528 }
 529
 530
 531 /*
 532  * Make FBO to render into given texture.
 533  */
 534 static GLuint
 535 MakeFBO_RenderTexture(GLuint texObj)
 536 {
 537    GLuint fb;
 538    GLint sizeFudge = 0;
 539
 540    glGenFramebuffers_func(1, &fb);
 541    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fb);
 542    /* Render color to texture */
 543    glFramebufferTexture2D_func(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
 544                              TexTarget, texObj, TextureLevel);
 545
 546    if (Use_ARB_fbo) {
 547       /* use a smaller depth buffer to see what happens */
 548       sizeFudge = 90;
 549    }
 550
 551    /* Setup depth and stencil buffers */
 552    {
 553       GLboolean b;
 554       b = AttachDepthAndStencilBuffers(fb,
 555                                        TexWidth - sizeFudge,
 556                                        TexHeight - sizeFudge,
 557                                        UsePackedDepthStencil,
 558                                        UsePackedDepthStencilBoth,
 559                                        &DepthRB, &StencilRB);
 560       if (!b) {
 561          /* try !UsePackedDepthStencil */
 562          b = AttachDepthAndStencilBuffers(fb,
 563                                           TexWidth - sizeFudge,
 564                                           TexHeight - sizeFudge,
 565                                           !UsePackedDepthStencil,
 566                                           UsePackedDepthStencilBoth,
 567                                           &DepthRB, &StencilRB);
 568       }
 569       if (!b) {
 570          printf("Unable to create/attach depth and stencil renderbuffers "
 571                 " to FBO!\n");
 572          exit(1);
 573       }
 574    }
 575
 576    /* queries */
 577    {
 578       GLint bits, w, h, name;
 579
 580       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, DepthRB);
 581       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 582                                       GL_RENDERBUFFER_WIDTH_EXT, &w);
 583       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 584                                       GL_RENDERBUFFER_HEIGHT_EXT, &h);
 585       printf("Color/Texture size: %d x %d\n", TexWidth, TexHeight);
 586       printf("Depth buffer size: %d x %d\n", w, h);
 587
 588       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 589                                       GL_RENDERBUFFER_DEPTH_SIZE_EXT, &bits);
 590       printf("Depth renderbuffer size = %d bits\n", bits);
 591
 592       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, StencilRB);
 593       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 594                                       GL_RENDERBUFFER_STENCIL_SIZE_EXT, &bits);
 595       printf("Stencil renderbuffer size = %d bits\n", bits);
 596
 597       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 598                                       GL_COLOR_ATTACHMENT0,
 599                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 600                                       &name);
 601       printf("Render to texture name: %d\n", texObj);
 602       printf("Color attachment[0] name: %d\n", name);
 603       assert(texObj == name);
 604
 605       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 606                                       GL_STENCIL_ATTACHMENT,
 607                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 608                                       &name);
 609       printf("Stencil attachment name: %d\n", name);
 610
 611       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 612                                       GL_DEPTH_ATTACHMENT,
 613                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 614                                       &name);
 615       printf("Depth attachment name: %d\n", name);
 616
 617    }
 618    /* bind the regular framebuffer */
 619    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 620
 621    return fb;
 622 }
 623
 624
 625 static void
 626 Init(void)
 627 {
 628    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 629       printf("GL_EXT_framebuffer_object not found!\n");
 630       exit(0);
 631    }
 632
 633    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 634
 635    SetupFunctionPointers();
 636
 637    /* lighting */
 638    {
 639       static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 };
 640       glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
 641    }
 642
 643    /*
 644     * Make texture object/image (we'll render into this texture)
 645     */
 646    {
 647       glGenTextures(1, &TexObj);
 648       glBindTexture(TexTarget, TexObj);
 649
 650       /* make two image levels */
 651       glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0,
 652                    GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 653       if (TexTarget == GL_TEXTURE_2D) {
 654          glTexImage2D(TexTarget, 1, TexIntFormat, TexWidth/2, TexHeight/2, 0,
 655                       GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 656          TexWidth = TexWidth >> TextureLevel;
 657          TexHeight = TexHeight >> TextureLevel;
 658          glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel);
 659       }
 660
 661       glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 662       glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 663       glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel);
 664       glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 665    }
 666
 667    MyFB = MakeFBO_RenderTexture(TexObj);
 668 }
 669
 670
 671 static void
 672 Usage(void)
 673 {
 674    printf("Usage:\n");
 675    printf("  -ds  Use combined depth/stencil renderbuffer\n");
 676    printf("  -arb Try GL_ARB_framebuffer_object's mismatched buffer sizes\n");
 677    printf("  -ds2 Try GL_ARB_framebuffer_object's GL_DEPTH_STENCIL_ATTACHMENT\n");
 678    printf("Keys:\n");
 679    printf("  a    Toggle animation\n");
 680    printf("  s/s  Step/rotate\n");
 681    printf("  c    Toggle back-face culling\n");
 682    printf("  w    Toggle wireframe mode (front-face only)\n");
 683    printf("  Esc  Exit\n");
 684 }
 685
 686
 687 int
 688 main(int argc, char *argv[])
 689 {
 690    glutInit(&argc, argv);
 691    glutInitWindowPosition(0, 0);
 692    glutInitWindowSize(Width, Height);
 693    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 694    Win = glutCreateWindow(argv[0]);
 695    glutReshapeFunc(Reshape);
 696    glutKeyboardFunc(Key);
 697    glutDisplayFunc(Display);
 698    if (Anim)
 699       glutIdleFunc(Idle);
 700
 701    ParseArgs(argc, argv);
 702    glewInit();
 703    Init();
 704    Usage();
 705
 706    glutMainLoop();
 707    return 0;
 708 }