progs/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 <GL/glut.h>
  13 #include <assert.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <math.h>
  18 #include "extfuncs.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 #if 1
  30 static GLenum TexTarget = GL_TEXTURE_2D;
  31 static int TexWidth = 512, TexHeight = 512;
  32 static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */
  33 #else
  34 static GLenum TexTarget = GL_TEXTURE_RECTANGLE_ARB;
  35 static int TexWidth = 200, TexHeight = 200;
  36 static GLenum TexIntFormat = GL_RGB5; /* either GL_RGB or GL_RGBA */
  37 #endif
  38 static GLuint TextureLevel = 0;  /* which texture level to render to */
  39
  40 static GLuint MyFB;
  41 static GLuint TexObj;
  42 static GLuint DepthRB = 0, StencilRB = 0;
  43 static GLboolean Anim = GL_FALSE;
  44 static GLfloat Rot = 0.0;
  45 static GLboolean UsePackedDepthStencil = GL_FALSE;
  46 static GLboolean UsePackedDepthStencilBoth = GL_FALSE;
  47 static GLboolean Use_ARB_fbo = GL_FALSE;
  48 static GLboolean Cull = GL_FALSE;
  49 static GLboolean Wireframe = GL_FALSE;
  50
  51
  52 static void
  53 CheckError(int line)
  54 {
  55    GLenum err = glGetError();
  56    if (err) {
  57       printf("GL Error 0x%x at line %d\n", (int) err, line);
  58    }
  59 }
  60
  61
  62 static void
  63 Idle(void)
  64 {
  65    Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
  66    glutPostRedisplay();
  67 }
  68
  69
  70 static void
  71 RenderTexture(void)
  72 {
  73    GLenum status;
  74
  75    glMatrixMode(GL_PROJECTION);
  76    glLoadIdentity();
  77    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  78    glMatrixMode(GL_MODELVIEW);
  79    glLoadIdentity();
  80    glTranslatef(0.0, 0.0, -15.0);
  81
  82    /* draw to texture image */
  83    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, MyFB);
  84
  85    status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
  86    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
  87       printf("Framebuffer incomplete!!!\n");
  88    }
  89
  90    glViewport(0, 0, TexWidth, TexHeight);
  91
  92    glClearColor(0.5, 0.5, 1.0, 0.0);
  93    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
  94    CheckError(__LINE__);
  95
  96 #if DEPTH
  97    glEnable(GL_DEPTH_TEST);
  98 #endif
  99
 100 #if STENCIL
 101    glEnable(GL_STENCIL_TEST);
 102    glStencilFunc(GL_NEVER, 1, ~0);
 103    glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE);
 104 #endif
 105
 106    CheckError(__LINE__);
 107
 108 #if DEPTH || STENCIL
 109    /* draw diamond-shaped stencil pattern */
 110    glColor3f(0, 1, 0);
 111    glBegin(GL_POLYGON);
 112    glVertex2f(-0.2,  0.0);
 113    glVertex2f( 0.0, -0.2);
 114    glVertex2f( 0.2,  0.0);
 115    glVertex2f( 0.0,  0.2);
 116    glEnd();
 117 #endif
 118
 119    /* draw teapot where stencil != 1 */
 120 #if STENCIL
 121    glStencilFunc(GL_NOTEQUAL, 1, ~0);
 122    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 123 #endif
 124
 125    CheckError(__LINE__);
 126
 127    if (Wireframe) {
 128       glPolygonMode(GL_FRONT, GL_LINE);
 129    }
 130    else {
 131       glPolygonMode(GL_FRONT, GL_FILL);
 132    }
 133
 134    if (Cull) {
 135       /* cull back */
 136       glCullFace(GL_BACK);
 137       glEnable(GL_CULL_FACE);
 138    }
 139    else {
 140       glDisable(GL_CULL_FACE);
 141    }
 142
 143 #if 0
 144    glBegin(GL_POLYGON);
 145    glColor3f(1, 0, 0);
 146    glVertex2f(-1, -1);
 147    glColor3f(0, 1, 0);
 148    glVertex2f(1, -1);
 149    glColor3f(0, 0, 1);
 150    glVertex2f(0, 1);
 151    glEnd();
 152 #else
 153    glEnable(GL_LIGHTING);
 154    glEnable(GL_LIGHT0);
 155    glPushMatrix();
 156    glRotatef(0.5 * Rot, 1.0, 0.0, 0.0);
 157    glFrontFace(GL_CW); /* Teapot patches backward */
 158    glutSolidTeapot(0.5);
 159    glFrontFace(GL_CCW);
 160    glPopMatrix();
 161    glDisable(GL_LIGHTING);
 162    /*
 163    PrintStencilHistogram(TexWidth, TexHeight);
 164    */
 165 #endif
 166
 167    glDisable(GL_DEPTH_TEST);
 168    glDisable(GL_STENCIL_TEST);
 169    glDisable(GL_CULL_FACE);
 170    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 171
 172 #if DRAW
 173    /* Bind normal framebuffer */
 174    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 175 #endif
 176
 177    CheckError(__LINE__);
 178 }
 179
 180
 181
 182 static void
 183 Display(void)
 184 {
 185    float ar = (float) Width / (float) Height;
 186
 187    RenderTexture();
 188
 189    /* draw textured quad in the window */
 190 #if DRAW
 191    glMatrixMode(GL_PROJECTION);
 192    glLoadIdentity();
 193    glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
 194    glMatrixMode(GL_MODELVIEW);
 195    glLoadIdentity();
 196    glTranslatef(0.0, 0.0, -7.0);
 197
 198    glViewport(0, 0, Width, Height);
 199
 200    glClearColor(0.25, 0.25, 0.25, 0);
 201    glClear(GL_COLOR_BUFFER_BIT);
 202
 203    glPushMatrix();
 204    glRotatef(Rot, 0, 1, 0);
 205    glEnable(TexTarget);
 206    glBindTexture(TexTarget, TexObj);
 207    glBegin(GL_POLYGON);
 208    glColor3f(0.25, 0.25, 0.25);
 209    if (TexTarget == GL_TEXTURE_2D) {
 210       glTexCoord2f(0, 0);
 211       glVertex2f(-1, -1);
 212       glTexCoord2f(1, 0);
 213       glVertex2f(1, -1);
 214       glColor3f(1.0, 1.0, 1.0);
 215       glTexCoord2f(1, 1);
 216       glVertex2f(1, 1);
 217       glTexCoord2f(0, 1);
 218       glVertex2f(-1, 1);
 219    }
 220    else {
 221       assert(TexTarget == GL_TEXTURE_RECTANGLE_ARB);
 222       glTexCoord2f(0, 0);
 223       glVertex2f(-1, -1);
 224       glTexCoord2f(TexWidth, 0);
 225       glVertex2f(1, -1);
 226       glColor3f(1.0, 1.0, 1.0);
 227       glTexCoord2f(TexWidth, TexHeight);
 228       glVertex2f(1, 1);
 229       glTexCoord2f(0, TexHeight);
 230       glVertex2f(-1, 1);
 231    }
 232    glEnd();
 233    glPopMatrix();
 234    glDisable(TexTarget);
 235 #endif
 236
 237    glutSwapBuffers();
 238    CheckError(__LINE__);
 239 }
 240
 241
 242 static void
 243 Reshape(int width, int height)
 244 {
 245    glViewport(0, 0, width, height);
 246    Width = width;
 247    Height = height;
 248 }
 249
 250
 251 static void
 252 CleanUp(void)
 253 {
 254 #if DEPTH
 255    glDeleteRenderbuffers_func(1, &DepthRB);
 256 #endif
 257 #if STENCIL
 258    glDeleteRenderbuffers_func(1, &StencilRB);
 259 #endif
 260    glDeleteFramebuffers_func(1, &MyFB);
 261
 262    glDeleteTextures(1, &TexObj);
 263
 264    glutDestroyWindow(Win);
 265
 266    exit(0);
 267 }
 268
 269
 270 static void
 271 Key(unsigned char key, int x, int y)
 272 {
 273    (void) x;
 274    (void) y;
 275    switch (key) {
 276    case 'a':
 277       Anim = !Anim;
 278       if (Anim)
 279          glutIdleFunc(Idle);
 280       else
 281          glutIdleFunc(NULL);
 282       break;
 283    case 'c':
 284       Cull = !Cull;
 285       break;
 286    case 'w':
 287       Wireframe = !Wireframe;
 288       break;
 289    case 's':
 290       Rot += 2.0;
 291       break;
 292    case 'S':
 293       Rot -= 2.0;
 294       break;
 295    case 27:
 296       CleanUp();
 297       break;
 298    }
 299    glutPostRedisplay();
 300 }
 301
 302
 303 /**
 304  * Attach depth and stencil renderbuffer(s) to the given framebuffer object.
 305  * \param tryDepthStencil  if true, try to use a combined depth+stencil buffer
 306  * \param bindDepthStencil  if true, and tryDepthStencil is true, bind with
 307  *                          the GL_DEPTH_STENCIL_ATTACHMENT target.
 308  * \return GL_TRUE for success, GL_FALSE for failure
 309  */
 310 static GLboolean
 311 AttachDepthAndStencilBuffers(GLuint fbo,
 312                              GLsizei width, GLsizei height,
 313                              GLboolean tryDepthStencil,
 314                              GLboolean bindDepthStencil,
 315                              GLuint *depthRbOut, GLuint *stencilRbOut)
 316 {
 317    GLenum status;
 318
 319    *depthRbOut = *stencilRbOut = 0;
 320
 321    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fbo);
 322
 323    if (tryDepthStencil) {
 324       GLuint rb;
 325
 326       glGenRenderbuffers_func(1, &rb);
 327       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 328       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 329                                GL_DEPTH24_STENCIL8_EXT,
 330                                width, height);
 331       if (glGetError())
 332          return GL_FALSE;
 333
 334       if (bindDepthStencil) {
 335          /* attach to both depth and stencil at once */
 336          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 337                                       GL_DEPTH_STENCIL_ATTACHMENT,
 338                                       GL_RENDERBUFFER_EXT, rb);
 339          if (glGetError())
 340             return GL_FALSE;
 341       }
 342       else {
 343          /* attach to depth attachment point */
 344          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 345                                       GL_DEPTH_ATTACHMENT_EXT,
 346                                       GL_RENDERBUFFER_EXT, rb);
 347          if (glGetError())
 348             return GL_FALSE;
 349
 350          /* and attach to stencil attachment point */
 351          glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 352                                       GL_STENCIL_ATTACHMENT_EXT,
 353                                       GL_RENDERBUFFER_EXT, rb);
 354          if (glGetError())
 355             return GL_FALSE;
 356       }
 357
 358       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 359       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
 360          return GL_FALSE;
 361
 362       *depthRbOut = *stencilRbOut = rb;
 363       return GL_TRUE;
 364    }
 365
 366    /* just depth renderbuffer */
 367    {
 368       GLuint rb;
 369
 370       glGenRenderbuffers_func(1, &rb);
 371       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 372       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 373                                GL_DEPTH_COMPONENT,
 374                                width, height);
 375       if (glGetError())
 376          return GL_FALSE;
 377
 378       /* attach to depth attachment point */
 379       glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 380                                    GL_DEPTH_ATTACHMENT_EXT,
 381                                    GL_RENDERBUFFER_EXT, rb);
 382       if (glGetError())
 383          return GL_FALSE;
 384
 385       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 386       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
 387          return GL_FALSE;
 388
 389       *depthRbOut = rb;
 390    }
 391
 392    /* just stencil renderbuffer */
 393    {
 394       GLuint rb;
 395
 396       glGenRenderbuffers_func(1, &rb);
 397       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
 398       glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
 399                                GL_STENCIL_INDEX,
 400                                width, height);
 401       if (glGetError())
 402          return GL_FALSE;
 403
 404       /* attach to depth attachment point */
 405       glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
 406                                    GL_STENCIL_ATTACHMENT_EXT,
 407                                    GL_RENDERBUFFER_EXT, rb);
 408       if (glGetError())
 409          return GL_FALSE;
 410
 411       status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
 412       if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 413          glDeleteRenderbuffers_func(1, depthRbOut);
 414          *depthRbOut = 0;
 415          glDeleteRenderbuffers_func(1, &rb);
 416          return GL_FALSE;
 417       }
 418
 419       *stencilRbOut = rb;
 420    }
 421
 422    return GL_TRUE;
 423 }
 424
 425
 426 static void
 427 ParseArgs(int argc, char *argv[])
 428 {
 429    GLint i;
 430    for (i = 1; i < argc; i++) {
 431       if (strcmp(argv[i], "-ds") == 0) {
 432          if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
 433             printf("GL_EXT_packed_depth_stencil not found!\n");
 434             exit(0);
 435          }
 436          UsePackedDepthStencil = GL_TRUE;
 437          printf("Using GL_EXT_packed_depth_stencil\n");
 438       }
 439       else if (strcmp(argv[i], "-ds2") == 0) {
 440          if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
 441             printf("GL_EXT_packed_depth_stencil not found!\n");
 442             exit(0);
 443          }
 444          if (!glutExtensionSupported("GL_ARB_framebuffer_object")) {
 445             printf("GL_ARB_framebuffer_object not found!\n");
 446             exit(0);
 447          }
 448          UsePackedDepthStencilBoth = GL_TRUE;
 449          printf("Using GL_EXT_packed_depth_stencil and GL_DEPTH_STENCIL attachment point\n");
 450       }
 451       else if (strcmp(argv[i], "-arb") == 0) {
 452          if (!glutExtensionSupported("GL_ARB_framebuffer_object")) {
 453             printf("Sorry, GL_ARB_framebuffer object not supported!\n");
 454          }
 455          else {
 456             Use_ARB_fbo = GL_TRUE;
 457          }
 458       }
 459       else {
 460          printf("Unknown option: %s\n", argv[i]);
 461       }
 462    }
 463 }
 464
 465
 466 static void
 467 SetupFunctionPointers(void)
 468 {
 469    GetExtensionFuncs();
 470
 471    if (Use_ARB_fbo) {
 472       /* no-op: use the ARB functions as-is */
 473    }
 474    else {
 475       /* set the ARB-flavor function pointers to point to the EXT functions */
 476       glIsRenderbuffer_func = glIsRenderbufferEXT_func;
 477       glBindRenderbuffer_func = glBindRenderbufferEXT_func;
 478       glDeleteRenderbuffers_func = glDeleteRenderbuffersEXT_func;
 479       glGenRenderbuffers_func = glGenRenderbuffersEXT_func;
 480       glRenderbufferStorage_func = glRenderbufferStorageEXT_func;
 481       glGetRenderbufferParameteriv_func = glGetRenderbufferParameterivEXT_func;
 482       glIsFramebuffer_func = glIsFramebufferEXT_func;
 483       glBindFramebuffer_func = glBindFramebufferEXT_func;
 484       glDeleteFramebuffers_func = glDeleteFramebuffersEXT_func;
 485       glGenFramebuffers_func = glGenFramebuffersEXT_func;
 486       glCheckFramebufferStatus_func = glCheckFramebufferStatusEXT_func;
 487       glFramebufferTexture1D_func = glFramebufferTexture1DEXT_func;
 488       glFramebufferTexture2D_func = glFramebufferTexture2DEXT_func;
 489       glFramebufferTexture3D_func = glFramebufferTexture3DEXT_func;
 490       glFramebufferRenderbuffer_func = glFramebufferRenderbufferEXT_func;
 491       glGetFramebufferAttachmentParameteriv_func = glGetFramebufferAttachmentParameterivEXT_func;
 492       glGenerateMipmap_func = glGenerateMipmapEXT_func;
 493    }
 494 }
 495
 496
 497 /*
 498  * Make FBO to render into given texture.
 499  */
 500 static GLuint
 501 MakeFBO_RenderTexture(GLuint texObj)
 502 {
 503    GLuint fb;
 504    GLint sizeFudge = 0;
 505
 506    glGenFramebuffers_func(1, &fb);
 507    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fb);
 508    /* Render color to texture */
 509    glFramebufferTexture2D_func(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
 510                              TexTarget, texObj, TextureLevel);
 511
 512    if (Use_ARB_fbo) {
 513       /* use a smaller depth buffer to see what happens */
 514       sizeFudge = 90;
 515    }
 516
 517    /* Setup depth and stencil buffers */
 518    {
 519       GLboolean b;
 520       b = AttachDepthAndStencilBuffers(fb,
 521                                        TexWidth - sizeFudge,
 522                                        TexHeight - sizeFudge,
 523                                        UsePackedDepthStencil,
 524                                        UsePackedDepthStencilBoth,
 525                                        &DepthRB, &StencilRB);
 526       if (!b) {
 527          /* try !UsePackedDepthStencil */
 528          b = AttachDepthAndStencilBuffers(fb,
 529                                           TexWidth - sizeFudge,
 530                                           TexHeight - sizeFudge,
 531                                           !UsePackedDepthStencil,
 532                                           UsePackedDepthStencilBoth,
 533                                           &DepthRB, &StencilRB);
 534       }
 535       if (!b) {
 536          printf("Unable to create/attach depth and stencil renderbuffers "
 537                 " to FBO!\n");
 538          exit(1);
 539       }
 540    }
 541
 542    /* queries */
 543    {
 544       GLint bits, w, h, name;
 545
 546       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, DepthRB);
 547       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 548                                       GL_RENDERBUFFER_WIDTH_EXT, &w);
 549       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 550                                       GL_RENDERBUFFER_HEIGHT_EXT, &h);
 551       printf("Color/Texture size: %d x %d\n", TexWidth, TexHeight);
 552       printf("Depth buffer size: %d x %d\n", w, h);
 553
 554       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 555                                       GL_RENDERBUFFER_DEPTH_SIZE_EXT, &bits);
 556       printf("Depth renderbuffer size = %d bits\n", bits);
 557
 558       glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, StencilRB);
 559       glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
 560                                       GL_RENDERBUFFER_STENCIL_SIZE_EXT, &bits);
 561       printf("Stencil renderbuffer size = %d bits\n", bits);
 562
 563       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 564                                       GL_COLOR_ATTACHMENT0,
 565                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 566                                       &name);
 567       printf("Render to texture name: %d\n", texObj);
 568       printf("Color attachment[0] name: %d\n", name);
 569       assert(texObj == name);
 570
 571       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 572                                       GL_STENCIL_ATTACHMENT,
 573                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 574                                       &name);
 575       printf("Stencil attachment name: %d\n", name);
 576
 577       glGetFramebufferAttachmentParameteriv_func(GL_FRAMEBUFFER_EXT,
 578                                       GL_DEPTH_ATTACHMENT,
 579                                       GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_EXT,
 580                                       &name);
 581       printf("Depth attachment name: %d\n", name);
 582
 583    }
 584    /* bind the regular framebuffer */
 585    glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 586
 587    return fb;
 588 }
 589
 590
 591 static void
 592 Init(void)
 593 {
 594    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 595       printf("GL_EXT_framebuffer_object not found!\n");
 596       exit(0);
 597    }
 598
 599    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 600
 601    SetupFunctionPointers();
 602
 603    /* lighting */
 604    {
 605       static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 };
 606       glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
 607    }
 608
 609    /*
 610     * Make texture object/image (we'll render into this texture)
 611     */
 612    {
 613       glGenTextures(1, &TexObj);
 614       glBindTexture(TexTarget, TexObj);
 615
 616       /* make two image levels */
 617       glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0,
 618                    GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 619       if (TexTarget == GL_TEXTURE_2D) {
 620          glTexImage2D(TexTarget, 1, TexIntFormat, TexWidth/2, TexHeight/2, 0,
 621                       GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 622          TexWidth = TexWidth >> TextureLevel;
 623          TexHeight = TexHeight >> TextureLevel;
 624          glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel);
 625       }
 626
 627       glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 628       glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 629       glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel);
 630       glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 631    }
 632
 633    MyFB = MakeFBO_RenderTexture(TexObj);
 634 }
 635
 636
 637 static void
 638 Usage(void)
 639 {
 640    printf("Usage:\n");
 641    printf("  -ds  Use combined depth/stencil renderbuffer\n");
 642    printf("  -arb Try GL_ARB_framebuffer_object's mismatched buffer sizes\n");
 643    printf("  -ds2 Try GL_ARB_framebuffer_object's GL_DEPTH_STENCIL_ATTACHMENT\n");
 644    printf("Keys:\n");
 645    printf("  a    Toggle animation\n");
 646    printf("  s/s  Step/rotate\n");
 647    printf("  c    Toggle back-face culling\n");
 648    printf("  w    Toggle wireframe mode (front-face only)\n");
 649    printf("  Esc  Exit\n");
 650 }
 651
 652
 653 int
 654 main(int argc, char *argv[])
 655 {
 656    glutInit(&argc, argv);
 657    glutInitWindowPosition(0, 0);
 658    glutInitWindowSize(Width, Height);
 659    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 660    Win = glutCreateWindow(argv[0]);
 661    glutReshapeFunc(Reshape);
 662    glutKeyboardFunc(Key);
 663    glutDisplayFunc(Display);
 664    if (Anim)
 665       glutIdleFunc(Idle);
 666
 667    ParseArgs(argc, argv);
 668    Init();
 669    Usage();
 670
 671    glutMainLoop();
 672    return 0;
 673 }