src/mesa/state_tracker/st_cb_fbo.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29 /**
  30  * Framebuffer/renderbuffer functions.
  31  *
  32  * \author Brian Paul
  33  */
  34
  35
  36 #include "main/imports.h"
  37 #include "main/context.h"
  38 #include "main/fbobject.h"
  39 #include "main/framebuffer.h"
  40 #include "main/renderbuffer.h"
  41
  42 #include "pipe/p_context.h"
  43 #include "pipe/p_defines.h"
  44 #include "pipe/p_screen.h"
  45 #include "st_context.h"
  46 #include "st_cb_fbo.h"
  47 #include "st_cb_texture.h"
  48 #include "st_format.h"
  49 #include "st_public.h"
  50 #include "st_texture.h"
  51
  52 #include "util/u_rect.h"
  53
  54
  55 /**
  56  * Compute the renderbuffer's Red/Green/EtcBit fields from the pipe format.
  57  */
  58 static int
  59 init_renderbuffer_bits(struct st_renderbuffer *strb,
  60                        enum pipe_format pipeFormat)
  61 {
  62    struct pipe_format_info info;
  63
  64    if (!st_get_format_info( pipeFormat, &info )) {
  65       assert( 0 );
  66    }
  67
  68    strb->Base.Format = info.mesa_format;
  69    strb->Base.DataType = st_format_datatype(pipeFormat);
  70
  71    return info.size;
  72 }
  73
  74 /**
  75  * gl_renderbuffer::AllocStorage()
  76  * This is called to allocate the original drawing surface, and
  77  * during window resize.
  78  */
  79 static GLboolean
  80 st_renderbuffer_alloc_storage(GLcontext * ctx, struct gl_renderbuffer *rb,
  81                               GLenum internalFormat,
  82                               GLuint width, GLuint height)
  83 {
  84    struct pipe_context *pipe = ctx->st->pipe;
  85    struct st_renderbuffer *strb = st_renderbuffer(rb);
  86    enum pipe_format format;
  87
  88    if (strb->format != PIPE_FORMAT_NONE)
  89       format = strb->format;
  90    else
  91       format = st_choose_renderbuffer_format(pipe->screen, internalFormat);
  92
  93    /* init renderbuffer fields */
  94    strb->Base.Width  = width;
  95    strb->Base.Height = height;
  96    init_renderbuffer_bits(strb, format);
  97
  98    strb->defined = GL_FALSE;  /* undefined contents now */
  99
 100    if(strb->software) {
 101       struct pipe_format_block block;
 102       size_t size;
 103
 104       _mesa_free(strb->data);
 105
 106       assert(strb->format != PIPE_FORMAT_NONE);
 107       pf_get_block(strb->format, &block);
 108
 109       strb->stride = pf_get_stride(&block, width);
 110       size = pf_get_2d_size(&block, strb->stride, height);
 111
 112       strb->data = _mesa_malloc(size);
 113
 114       return strb->data != NULL;
 115    }
 116    else {
 117       struct pipe_texture template;
 118       unsigned surface_usage;
 119
 120       /* Free the old surface and texture
 121        */
 122       pipe_surface_reference( &strb->surface, NULL );
 123       pipe_texture_reference( &strb->texture, NULL );
 124
 125       /* Setup new texture template.
 126        */
 127       memset(&template, 0, sizeof(template));
 128       template.target = PIPE_TEXTURE_2D;
 129       template.format = format;
 130       pf_get_block(format, &template.block);
 131       template.width[0] = width;
 132       template.height[0] = height;
 133       template.depth[0] = 1;
 134       template.last_level = 0;
 135       template.nr_samples = rb->NumSamples;
 136       if (pf_is_depth_stencil(format)) {
 137          template.tex_usage = PIPE_TEXTURE_USAGE_DEPTH_STENCIL;
 138       }
 139       else {
 140          template.tex_usage = (PIPE_TEXTURE_USAGE_DISPLAY_TARGET |
 141                                PIPE_TEXTURE_USAGE_RENDER_TARGET);
 142       }
 143
 144       /* Probably need dedicated flags for surface usage too:
 145        */
 146       surface_usage = (PIPE_BUFFER_USAGE_GPU_READ |
 147                        PIPE_BUFFER_USAGE_GPU_WRITE);
 148 #if 0
 149                        PIPE_BUFFER_USAGE_CPU_READ |
 150                        PIPE_BUFFER_USAGE_CPU_WRITE);
 151 #endif
 152
 153       strb->texture = pipe->screen->texture_create( pipe->screen,
 154                                                     &template );
 155
 156       if (!strb->texture)
 157          return FALSE;
 158
 159       strb->surface = pipe->screen->get_tex_surface( pipe->screen,
 160                                                      strb->texture,
 161                                                      0, 0, 0,
 162                                                      surface_usage );
 163       if (strb->surface) {
 164          assert(strb->surface->texture);
 165          assert(strb->surface->format);
 166          assert(strb->surface->width == width);
 167          assert(strb->surface->height == height);
 168       }
 169
 170       return strb->surface != NULL;
 171    }
 172 }
 173
 174
 175 /**
 176  * gl_renderbuffer::Delete()
 177  */
 178 static void
 179 st_renderbuffer_delete(struct gl_renderbuffer *rb)
 180 {
 181    struct st_renderbuffer *strb = st_renderbuffer(rb);
 182    ASSERT(strb);
 183    pipe_surface_reference(&strb->surface, NULL);
 184    pipe_texture_reference(&strb->texture, NULL);
 185    _mesa_free(strb->data);
 186    _mesa_free(strb);
 187 }
 188
 189
 190 /**
 191  * gl_renderbuffer::GetPointer()
 192  */
 193 static void *
 194 null_get_pointer(GLcontext * ctx, struct gl_renderbuffer *rb,
 195                  GLint x, GLint y)
 196 {
 197    /* By returning NULL we force all software rendering to go through
 198     * the span routines.
 199     */
 200 #if 0
 201    assert(0);  /* Should never get called with softpipe */
 202 #endif
 203    return NULL;
 204 }
 205
 206
 207 /**
 208  * Called via ctx->Driver.NewFramebuffer()
 209  */
 210 static struct gl_framebuffer *
 211 st_new_framebuffer(GLcontext *ctx, GLuint name)
 212 {
 213    /* XXX not sure we need to subclass gl_framebuffer for pipe */
 214    return _mesa_new_framebuffer(ctx, name);
 215 }
 216
 217
 218 /**
 219  * Called via ctx->Driver.NewRenderbuffer()
 220  */
 221 static struct gl_renderbuffer *
 222 st_new_renderbuffer(GLcontext *ctx, GLuint name)
 223 {
 224    struct st_renderbuffer *strb = ST_CALLOC_STRUCT(st_renderbuffer);
 225    if (strb) {
 226       _mesa_init_renderbuffer(&strb->Base, name);
 227       strb->Base.Delete = st_renderbuffer_delete;
 228       strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 229       strb->Base.GetPointer = null_get_pointer;
 230       strb->format = PIPE_FORMAT_NONE;
 231       return &strb->Base;
 232    }
 233    return NULL;
 234 }
 235
 236
 237 /**
 238  * Allocate a renderbuffer for a an on-screen window (not a user-created
 239  * renderbuffer).  The window system code determines the format.
 240  */
 241 struct gl_renderbuffer *
 242 st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw)
 243 {
 244    struct st_renderbuffer *strb;
 245
 246    strb = ST_CALLOC_STRUCT(st_renderbuffer);
 247    if (!strb) {
 248       _mesa_error(NULL, GL_OUT_OF_MEMORY, "creating renderbuffer");
 249       return NULL;
 250    }
 251
 252    _mesa_init_renderbuffer(&strb->Base, 0);
 253    strb->Base.ClassID = 0x4242; /* just a unique value */
 254    strb->Base.NumSamples = samples;
 255    strb->format = format;
 256    init_renderbuffer_bits(strb, format);
 257    strb->software = sw;
 258
 259    switch (format) {
 260    case PIPE_FORMAT_A8R8G8B8_UNORM:
 261    case PIPE_FORMAT_B8G8R8A8_UNORM:
 262    case PIPE_FORMAT_X8R8G8B8_UNORM:
 263    case PIPE_FORMAT_B8G8R8X8_UNORM:
 264    case PIPE_FORMAT_A1R5G5B5_UNORM:
 265    case PIPE_FORMAT_A4R4G4B4_UNORM:
 266    case PIPE_FORMAT_R5G6B5_UNORM:
 267       strb->Base.InternalFormat = GL_RGBA;
 268       break;
 269    case PIPE_FORMAT_Z16_UNORM:
 270       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 271       break;
 272    case PIPE_FORMAT_Z32_UNORM:
 273       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 274       break;
 275    case PIPE_FORMAT_S8Z24_UNORM:
 276    case PIPE_FORMAT_Z24S8_UNORM:
 277    case PIPE_FORMAT_X8Z24_UNORM:
 278    case PIPE_FORMAT_Z24X8_UNORM:
 279       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 280       break;
 281    case PIPE_FORMAT_S8_UNORM:
 282       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 283       break;
 284    case PIPE_FORMAT_R16G16B16A16_SNORM:
 285       strb->Base.InternalFormat = GL_RGBA16;
 286       break;
 287    default:
 288       _mesa_problem(NULL,
 289                     "Unexpected format in st_new_renderbuffer_fb");
 290       _mesa_free(strb);
 291       return NULL;
 292    }
 293
 294    /* st-specific methods */
 295    strb->Base.Delete = st_renderbuffer_delete;
 296    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 297    strb->Base.GetPointer = null_get_pointer;
 298
 299    /* surface is allocated in st_renderbuffer_alloc_storage() */
 300    strb->surface = NULL;
 301
 302    return &strb->Base;
 303 }
 304
 305
 306
 307
 308 /**
 309  * Called via ctx->Driver.BindFramebufferEXT().
 310  */
 311 static void
 312 st_bind_framebuffer(GLcontext *ctx, GLenum target,
 313                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 314 {
 315
 316 }
 317
 318 /**
 319  * Called by ctx->Driver.FramebufferRenderbuffer
 320  */
 321 static void
 322 st_framebuffer_renderbuffer(GLcontext *ctx,
 323                             struct gl_framebuffer *fb,
 324                             GLenum attachment,
 325                             struct gl_renderbuffer *rb)
 326 {
 327    /* XXX no need for derivation? */
 328    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 329 }
 330
 331
 332 /**
 333  * Called by ctx->Driver.RenderTexture
 334  */
 335 static void
 336 st_render_texture(GLcontext *ctx,
 337                   struct gl_framebuffer *fb,
 338                   struct gl_renderbuffer_attachment *att)
 339 {
 340    struct pipe_screen *screen = ctx->st->pipe->screen;
 341    struct st_renderbuffer *strb;
 342    struct gl_renderbuffer *rb;
 343    struct pipe_texture *pt = st_get_texobj_texture(att->Texture);
 344    struct st_texture_object *stObj;
 345    const struct gl_texture_image *texImage =
 346       att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 347
 348    if (!pt)
 349       return;
 350
 351    /* create new renderbuffer which wraps the texture image */
 352    rb = st_new_renderbuffer(ctx, 0);
 353    if (!rb) {
 354       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 355       return;
 356    }
 357
 358    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 359    assert(rb->RefCount == 1);
 360    rb->AllocStorage = NULL; /* should not get called */
 361    strb = st_renderbuffer(rb);
 362
 363    assert(strb->Base.RefCount > 0);
 364
 365    /* get the texture for the texture object */
 366    stObj = st_texture_object(att->Texture);
 367
 368    /* point renderbuffer at texobject */
 369    strb->rtt = stObj;
 370    strb->rtt_level = att->TextureLevel;
 371    strb->rtt_face = att->CubeMapFace;
 372    strb->rtt_slice = att->Zoffset;
 373
 374    rb->Width = texImage->Width2;
 375    rb->Height = texImage->Height2;
 376    rb->_BaseFormat = texImage->_BaseFormat;
 377    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 378
 379    /*printf("***** pipe texture %d x %d\n", pt->width[0], pt->height[0]);*/
 380
 381    pipe_texture_reference( &strb->texture, pt );
 382
 383    pipe_surface_reference(&strb->surface, NULL);
 384
 385    /* new surface for rendering into the texture */
 386    strb->surface = screen->get_tex_surface(screen,
 387                                            strb->texture,
 388                                            strb->rtt_face,
 389                                            strb->rtt_level,
 390                                            strb->rtt_slice,
 391                                            PIPE_BUFFER_USAGE_GPU_READ |
 392                                            PIPE_BUFFER_USAGE_GPU_WRITE);
 393
 394    init_renderbuffer_bits(strb, pt->format);
 395
 396    /*
 397    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 398           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 399    */
 400
 401    /* Invalidate buffer state so that the pipe's framebuffer state
 402     * gets updated.
 403     * That's where the new renderbuffer (which we just created) gets
 404     * passed to the pipe as a (color/depth) render target.
 405     */
 406    st_invalidate_state(ctx, _NEW_BUFFERS);
 407 }
 408
 409
 410 /**
 411  * Called via ctx->Driver.FinishRenderTexture.
 412  */
 413 static void
 414 st_finish_render_texture(GLcontext *ctx,
 415                          struct gl_renderbuffer_attachment *att)
 416 {
 417    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 418
 419    if (!strb)
 420       return;
 421
 422    st_flush( ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL );
 423
 424    if (strb->surface)
 425       pipe_surface_reference( &strb->surface, NULL );
 426
 427    strb->rtt = NULL;
 428
 429    /*
 430    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 431    */
 432
 433    _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 434
 435    /* restore previous framebuffer state */
 436    st_invalidate_state(ctx, _NEW_BUFFERS);
 437 }
 438
 439
 440 /**
 441  * Validate a renderbuffer attachment for a particular usage.
 442  */
 443
 444 static GLboolean
 445 st_validate_attachment(struct pipe_screen *screen,
 446                        const struct gl_renderbuffer_attachment *att,
 447                        GLuint usage)
 448 {
 449    const struct st_texture_object *stObj =
 450       st_texture_object(att->Texture);
 451
 452    /**
 453     * Only validate texture attachments for now, since
 454     * st_renderbuffer_alloc_storage makes sure that
 455     * the format is supported.
 456     */
 457
 458    if (att->Type != GL_TEXTURE)
 459       return GL_TRUE;
 460
 461    if (!stObj)
 462       return GL_FALSE;
 463
 464    return screen->is_format_supported(screen, stObj->pt->format,
 465                                       PIPE_TEXTURE_2D,
 466                                       usage, 0);
 467 }
 468
 469 /**
 470  * Check that the framebuffer configuration is valid in terms of what
 471  * the driver can support.
 472  *
 473  * For Gallium we only supports combined Z+stencil, not separate buffers.
 474  */
 475 static void
 476 st_validate_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 477 {
 478    struct pipe_screen *screen = ctx->st->pipe->screen;
 479    const struct gl_renderbuffer *depthRb =
 480       fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 481    const struct gl_renderbuffer *stencilRb =
 482       fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 483    GLuint i;
 484
 485    if (stencilRb && depthRb && stencilRb != depthRb) {
 486       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 487       return;
 488    }
 489
 490    if (!st_validate_attachment(screen,
 491                                &fb->Attachment[BUFFER_DEPTH],
 492                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 493       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 494       return;
 495    }
 496    if (!st_validate_attachment(screen,
 497                                &fb->Attachment[BUFFER_STENCIL],
 498                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 499       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 500       return;
 501    }
 502    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 503       if (!st_validate_attachment(screen,
 504                                   &fb->Attachment[BUFFER_COLOR0 + i],
 505                                   PIPE_TEXTURE_USAGE_RENDER_TARGET)) {
 506          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 507          return;
 508       }
 509    }
 510 }
 511
 512
 513 /**
 514  * Copy back color buffer to front color buffer.
 515  */
 516 static void
 517 copy_back_to_front(struct st_context *st,
 518                    struct gl_framebuffer *fb,
 519                    gl_buffer_index frontIndex,
 520                    gl_buffer_index backIndex)
 521
 522 {
 523    struct st_framebuffer *stfb = (struct st_framebuffer *) fb;
 524    struct pipe_surface *surf_front, *surf_back;
 525
 526    (void) st_get_framebuffer_surface(stfb, frontIndex, &surf_front);
 527    (void) st_get_framebuffer_surface(stfb, backIndex, &surf_back);
 528
 529    if (surf_front && surf_back) {
 530       if (st->pipe->surface_copy) {
 531          st->pipe->surface_copy(st->pipe,
 532                                 surf_front, 0, 0,  /* dest */
 533                                 surf_back, 0, 0,   /* src */
 534                                 fb->Width, fb->Height);
 535       } else {
 536          util_surface_copy(st->pipe, FALSE,
 537                            surf_front, 0, 0,
 538                            surf_back, 0, 0,
 539                            fb->Width, fb->Height);
 540       }
 541    }
 542 }
 543
 544
 545 /**
 546  * Check if we're drawing into, or read from, a front color buffer.  If the
 547  * front buffer is missing, create it now.
 548  *
 549  * The back color buffer must exist since we'll use its format/samples info
 550  * for creating the front buffer.
 551  *
 552  * \param frontIndex  either BUFFER_FRONT_LEFT or BUFFER_FRONT_RIGHT
 553  * \param backIndex  either BUFFER_BACK_LEFT or BUFFER_BACK_RIGHT
 554  */
 555 static void
 556 check_create_front_buffer(GLcontext *ctx, struct gl_framebuffer *fb,
 557                           gl_buffer_index frontIndex,
 558                           gl_buffer_index backIndex)
 559 {
 560    if (fb->Attachment[frontIndex].Renderbuffer == NULL) {
 561       GLboolean create = GL_FALSE;
 562
 563       /* check if drawing to or reading from front buffer */
 564       if (fb->_ColorReadBufferIndex == frontIndex) {
 565          create = GL_TRUE;
 566       }
 567       else {
 568          GLuint b;
 569          for (b = 0; b < fb->_NumColorDrawBuffers; b++) {
 570             if (fb->_ColorDrawBufferIndexes[b] == frontIndex) {
 571                create = GL_TRUE;
 572                break;
 573             }
 574          }
 575       }
 576
 577       if (create) {
 578          struct st_renderbuffer *back;
 579          struct gl_renderbuffer *front;
 580          enum pipe_format colorFormat;
 581          uint samples;
 582
 583          if (0)
 584             _mesa_debug(ctx, "Allocate new front buffer\n");
 585
 586          /* get back renderbuffer info */
 587          back = st_renderbuffer(fb->Attachment[backIndex].Renderbuffer);
 588          colorFormat = back->format;
 589          samples = back->Base.NumSamples;
 590
 591          /* create front renderbuffer */
 592          front = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
 593          _mesa_add_renderbuffer(fb, frontIndex, front);
 594
 595          /* alloc texture/surface for new front buffer */
 596          front->AllocStorage(ctx, front, front->InternalFormat,
 597                              fb->Width, fb->Height);
 598
 599          /* initialize the front color buffer contents by copying
 600           * the back buffer.
 601           */
 602          copy_back_to_front(ctx->st, fb, frontIndex, backIndex);
 603       }
 604    }
 605 }
 606
 607
 608 /**
 609  * If front left/right color buffers are missing, create them now.
 610  */
 611 static void
 612 check_create_front_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 613 {
 614    /* check if we need to create the front left buffer now */
 615    check_create_front_buffer(ctx, fb, BUFFER_FRONT_LEFT, BUFFER_BACK_LEFT);
 616
 617    if (fb->Visual.stereoMode) {
 618       check_create_front_buffer(ctx, fb, BUFFER_FRONT_RIGHT, BUFFER_BACK_RIGHT);
 619    }
 620
 621    st_invalidate_state(ctx, _NEW_BUFFERS);
 622 }
 623
 624
 625 /**
 626  * Called via glDrawBuffer.
 627  */
 628 static void
 629 st_DrawBuffers(GLcontext *ctx, GLsizei count, const GLenum *buffers)
 630 {
 631    (void) count;
 632    (void) buffers;
 633    check_create_front_buffers(ctx, ctx->DrawBuffer);
 634 }
 635
 636
 637 /**
 638  * Called via glReadBuffer.
 639  */
 640 static void
 641 st_ReadBuffer(GLcontext *ctx, GLenum buffer)
 642 {
 643    (void) buffer;
 644    check_create_front_buffers(ctx, ctx->ReadBuffer);
 645 }
 646
 647
 648 void st_init_fbo_functions(struct dd_function_table *functions)
 649 {
 650    functions->NewFramebuffer = st_new_framebuffer;
 651    functions->NewRenderbuffer = st_new_renderbuffer;
 652    functions->BindFramebuffer = st_bind_framebuffer;
 653    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 654    functions->RenderTexture = st_render_texture;
 655    functions->FinishRenderTexture = st_finish_render_texture;
 656    functions->ValidateFramebuffer = st_validate_framebuffer;
 657    /* no longer needed by core Mesa, drivers handle resizes...
 658    functions->ResizeBuffers = st_resize_buffers;
 659    */
 660
 661    functions->DrawBuffers = st_DrawBuffers;
 662    functions->ReadBuffer = st_ReadBuffer;
 663 }