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/macros.h"
  41 #include "main/renderbuffer.h"
  42
  43 #include "pipe/p_context.h"
  44 #include "pipe/p_defines.h"
  45 #include "pipe/p_screen.h"
  46 #include "st_context.h"
  47 #include "st_cb_fbo.h"
  48 #include "st_format.h"
  49 #include "st_public.h"
  50 #include "st_texture.h"
  51
  52 #include "util/u_format.h"
  53 #include "util/u_rect.h"
  54 #include "util/u_inlines.h"
  55
  56
  57 /**
  58  * Compute the renderbuffer's Red/Green/EtcBit fields from the pipe format.
  59  */
  60 static int
  61 init_renderbuffer_bits(struct st_renderbuffer *strb,
  62                        enum pipe_format pipeFormat)
  63 {
  64    struct pipe_format_info info;
  65
  66    if (!st_get_format_info( pipeFormat, &info )) {
  67       assert( 0 );
  68    }
  69
  70    strb->Base.Format = info.mesa_format;
  71    strb->Base.DataType = st_format_datatype(pipeFormat);
  72
  73    return info.size;
  74 }
  75
  76 /**
  77  * gl_renderbuffer::AllocStorage()
  78  * This is called to allocate the original drawing surface, and
  79  * during window resize.
  80  */
  81 static GLboolean
  82 st_renderbuffer_alloc_storage(GLcontext * ctx, struct gl_renderbuffer *rb,
  83                               GLenum internalFormat,
  84                               GLuint width, GLuint height)
  85 {
  86    struct pipe_context *pipe = ctx->st->pipe;
  87    struct st_renderbuffer *strb = st_renderbuffer(rb);
  88    enum pipe_format format;
  89
  90    if (strb->format != PIPE_FORMAT_NONE)
  91       format = strb->format;
  92    else
  93       format = st_choose_renderbuffer_format(pipe->screen, internalFormat);
  94
  95    /* init renderbuffer fields */
  96    strb->Base.Width  = width;
  97    strb->Base.Height = height;
  98    init_renderbuffer_bits(strb, format);
  99
 100    strb->defined = GL_FALSE;  /* undefined contents now */
 101
 102    if(strb->software) {
 103       size_t size;
 104
 105       free(strb->data);
 106
 107       assert(strb->format != PIPE_FORMAT_NONE);
 108
 109       strb->stride = util_format_get_stride(strb->format, width);
 110       size = util_format_get_2d_size(strb->format, strb->stride, height);
 111
 112       strb->data = 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       template.width0 = width;
 131       template.height0 = height;
 132       template.depth0 = 1;
 133       template.last_level = 0;
 134       template.nr_samples = rb->NumSamples;
 135       if (util_format_is_depth_or_stencil(format)) {
 136          template.tex_usage = PIPE_TEXTURE_USAGE_DEPTH_STENCIL;
 137       }
 138       else {
 139          template.tex_usage = (PIPE_TEXTURE_USAGE_DISPLAY_TARGET |
 140                                PIPE_TEXTURE_USAGE_RENDER_TARGET);
 141       }
 142
 143       /* Probably need dedicated flags for surface usage too:
 144        */
 145       surface_usage = (PIPE_BUFFER_USAGE_GPU_READ |
 146                        PIPE_BUFFER_USAGE_GPU_WRITE);
 147 #if 0
 148                        PIPE_BUFFER_USAGE_CPU_READ |
 149                        PIPE_BUFFER_USAGE_CPU_WRITE);
 150 #endif
 151
 152       strb->texture = pipe->screen->texture_create( pipe->screen,
 153                                                     &template );
 154
 155       if (!strb->texture)
 156          return FALSE;
 157
 158       strb->surface = pipe->screen->get_tex_surface( pipe->screen,
 159                                                      strb->texture,
 160                                                      0, 0, 0,
 161                                                      surface_usage );
 162       if (strb->surface) {
 163          assert(strb->surface->texture);
 164          assert(strb->surface->format);
 165          assert(strb->surface->width == width);
 166          assert(strb->surface->height == height);
 167       }
 168
 169       return strb->surface != NULL;
 170    }
 171 }
 172
 173
 174 /**
 175  * gl_renderbuffer::Delete()
 176  */
 177 static void
 178 st_renderbuffer_delete(struct gl_renderbuffer *rb)
 179 {
 180    struct st_renderbuffer *strb = st_renderbuffer(rb);
 181    ASSERT(strb);
 182    pipe_surface_reference(&strb->surface, NULL);
 183    pipe_texture_reference(&strb->texture, NULL);
 184    free(strb->data);
 185    free(strb);
 186 }
 187
 188
 189 /**
 190  * gl_renderbuffer::GetPointer()
 191  */
 192 static void *
 193 null_get_pointer(GLcontext * ctx, struct gl_renderbuffer *rb,
 194                  GLint x, GLint y)
 195 {
 196    /* By returning NULL we force all software rendering to go through
 197     * the span routines.
 198     */
 199 #if 0
 200    assert(0);  /* Should never get called with softpipe */
 201 #endif
 202    return NULL;
 203 }
 204
 205
 206 /**
 207  * Called via ctx->Driver.NewFramebuffer()
 208  */
 209 static struct gl_framebuffer *
 210 st_new_framebuffer(GLcontext *ctx, GLuint name)
 211 {
 212    /* XXX not sure we need to subclass gl_framebuffer for pipe */
 213    return _mesa_new_framebuffer(ctx, name);
 214 }
 215
 216
 217 /**
 218  * Called via ctx->Driver.NewRenderbuffer()
 219  */
 220 static struct gl_renderbuffer *
 221 st_new_renderbuffer(GLcontext *ctx, GLuint name)
 222 {
 223    struct st_renderbuffer *strb = ST_CALLOC_STRUCT(st_renderbuffer);
 224    if (strb) {
 225       _mesa_init_renderbuffer(&strb->Base, name);
 226       strb->Base.Delete = st_renderbuffer_delete;
 227       strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 228       strb->Base.GetPointer = null_get_pointer;
 229       strb->format = PIPE_FORMAT_NONE;
 230       return &strb->Base;
 231    }
 232    return NULL;
 233 }
 234
 235
 236 /**
 237  * Allocate a renderbuffer for a an on-screen window (not a user-created
 238  * renderbuffer).  The window system code determines the format.
 239  */
 240 struct gl_renderbuffer *
 241 st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw)
 242 {
 243    struct st_renderbuffer *strb;
 244
 245    strb = ST_CALLOC_STRUCT(st_renderbuffer);
 246    if (!strb) {
 247       _mesa_error(NULL, GL_OUT_OF_MEMORY, "creating renderbuffer");
 248       return NULL;
 249    }
 250
 251    _mesa_init_renderbuffer(&strb->Base, 0);
 252    strb->Base.ClassID = 0x4242; /* just a unique value */
 253    strb->Base.NumSamples = samples;
 254    strb->format = format;
 255    init_renderbuffer_bits(strb, format);
 256    strb->software = sw;
 257
 258    switch (format) {
 259    case PIPE_FORMAT_A8R8G8B8_UNORM:
 260    case PIPE_FORMAT_B8G8R8A8_UNORM:
 261    case PIPE_FORMAT_X8R8G8B8_UNORM:
 262    case PIPE_FORMAT_B8G8R8X8_UNORM:
 263    case PIPE_FORMAT_A1R5G5B5_UNORM:
 264    case PIPE_FORMAT_A4R4G4B4_UNORM:
 265    case PIPE_FORMAT_R5G6B5_UNORM:
 266       strb->Base.InternalFormat = GL_RGBA;
 267       break;
 268    case PIPE_FORMAT_Z16_UNORM:
 269       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 270       break;
 271    case PIPE_FORMAT_Z32_UNORM:
 272       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 273       break;
 274    case PIPE_FORMAT_S8Z24_UNORM:
 275    case PIPE_FORMAT_Z24S8_UNORM:
 276    case PIPE_FORMAT_X8Z24_UNORM:
 277    case PIPE_FORMAT_Z24X8_UNORM:
 278       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 279       break;
 280    case PIPE_FORMAT_S8_UNORM:
 281       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 282       break;
 283    case PIPE_FORMAT_R16G16B16A16_SNORM:
 284       strb->Base.InternalFormat = GL_RGBA16;
 285       break;
 286    default:
 287       _mesa_problem(NULL,
 288                     "Unexpected format in st_new_renderbuffer_fb");
 289       free(strb);
 290       return NULL;
 291    }
 292
 293    /* st-specific methods */
 294    strb->Base.Delete = st_renderbuffer_delete;
 295    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 296    strb->Base.GetPointer = null_get_pointer;
 297
 298    /* surface is allocated in st_renderbuffer_alloc_storage() */
 299    strb->surface = NULL;
 300
 301    return &strb->Base;
 302 }
 303
 304
 305
 306
 307 /**
 308  * Called via ctx->Driver.BindFramebufferEXT().
 309  */
 310 static void
 311 st_bind_framebuffer(GLcontext *ctx, GLenum target,
 312                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 313 {
 314
 315 }
 316
 317 /**
 318  * Called by ctx->Driver.FramebufferRenderbuffer
 319  */
 320 static void
 321 st_framebuffer_renderbuffer(GLcontext *ctx,
 322                             struct gl_framebuffer *fb,
 323                             GLenum attachment,
 324                             struct gl_renderbuffer *rb)
 325 {
 326    /* XXX no need for derivation? */
 327    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 328 }
 329
 330
 331 /**
 332  * Called by ctx->Driver.RenderTexture
 333  */
 334 static void
 335 st_render_texture(GLcontext *ctx,
 336                   struct gl_framebuffer *fb,
 337                   struct gl_renderbuffer_attachment *att)
 338 {
 339    struct pipe_screen *screen = ctx->st->pipe->screen;
 340    struct st_renderbuffer *strb;
 341    struct gl_renderbuffer *rb;
 342    struct pipe_texture *pt = st_get_texobj_texture(att->Texture);
 343    struct st_texture_object *stObj;
 344    const struct gl_texture_image *texImage;
 345    GLint pt_level;
 346
 347    /* When would this fail?  Perhaps assert? */
 348    if (!pt)
 349       return;
 350
 351    /* The first gallium texture level = Mesa BaseLevel */
 352    pt_level = MAX2(0, (GLint) att->TextureLevel - att->Texture->BaseLevel);
 353    texImage = att->Texture->Image[att->CubeMapFace][pt_level];
 354
 355    /* create new renderbuffer which wraps the texture image */
 356    rb = st_new_renderbuffer(ctx, 0);
 357    if (!rb) {
 358       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 359       return;
 360    }
 361
 362    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 363    assert(rb->RefCount == 1);
 364    rb->AllocStorage = NULL; /* should not get called */
 365    strb = st_renderbuffer(rb);
 366
 367    assert(strb->Base.RefCount > 0);
 368
 369    /* get the texture for the texture object */
 370    stObj = st_texture_object(att->Texture);
 371
 372    /* point renderbuffer at texobject */
 373    strb->rtt = stObj;
 374    strb->rtt_level = pt_level;
 375    strb->rtt_face = att->CubeMapFace;
 376    strb->rtt_slice = att->Zoffset;
 377
 378    rb->Width = texImage->Width2;
 379    rb->Height = texImage->Height2;
 380    rb->_BaseFormat = texImage->_BaseFormat;
 381    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 382
 383    /*printf("***** pipe texture %d x %d\n", pt->width0, pt->height0);*/
 384
 385    pipe_texture_reference( &strb->texture, pt );
 386
 387    pipe_surface_reference(&strb->surface, NULL);
 388
 389    assert(strb->rtt_level <= strb->texture->last_level);
 390
 391    /* new surface for rendering into the texture */
 392    strb->surface = screen->get_tex_surface(screen,
 393                                            strb->texture,
 394                                            strb->rtt_face,
 395                                            strb->rtt_level,
 396                                            strb->rtt_slice,
 397                                            PIPE_BUFFER_USAGE_GPU_READ |
 398                                            PIPE_BUFFER_USAGE_GPU_WRITE);
 399
 400    init_renderbuffer_bits(strb, pt->format);
 401
 402    /*
 403    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 404           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 405    */
 406
 407    /* Invalidate buffer state so that the pipe's framebuffer state
 408     * gets updated.
 409     * That's where the new renderbuffer (which we just created) gets
 410     * passed to the pipe as a (color/depth) render target.
 411     */
 412    st_invalidate_state(ctx, _NEW_BUFFERS);
 413 }
 414
 415
 416 /**
 417  * Called via ctx->Driver.FinishRenderTexture.
 418  */
 419 static void
 420 st_finish_render_texture(GLcontext *ctx,
 421                          struct gl_renderbuffer_attachment *att)
 422 {
 423    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 424
 425    if (!strb)
 426       return;
 427
 428    st_flush( ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL );
 429
 430    if (strb->surface)
 431       pipe_surface_reference( &strb->surface, NULL );
 432
 433    strb->rtt = NULL;
 434
 435    /*
 436    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 437    */
 438
 439    _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 440
 441    /* restore previous framebuffer state */
 442    st_invalidate_state(ctx, _NEW_BUFFERS);
 443 }
 444
 445
 446 /**
 447  * Validate a renderbuffer attachment for a particular usage.
 448  */
 449
 450 static GLboolean
 451 st_validate_attachment(struct pipe_screen *screen,
 452                        const struct gl_renderbuffer_attachment *att,
 453                        GLuint usage)
 454 {
 455    const struct st_texture_object *stObj =
 456       st_texture_object(att->Texture);
 457
 458    /**
 459     * Only validate texture attachments for now, since
 460     * st_renderbuffer_alloc_storage makes sure that
 461     * the format is supported.
 462     */
 463
 464    if (att->Type != GL_TEXTURE)
 465       return GL_TRUE;
 466
 467    if (!stObj)
 468       return GL_FALSE;
 469
 470    return screen->is_format_supported(screen, stObj->pt->format,
 471                                       PIPE_TEXTURE_2D,
 472                                       usage, 0);
 473 }
 474
 475 /**
 476  * Check that the framebuffer configuration is valid in terms of what
 477  * the driver can support.
 478  *
 479  * For Gallium we only supports combined Z+stencil, not separate buffers.
 480  */
 481 static void
 482 st_validate_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 483 {
 484    struct pipe_screen *screen = ctx->st->pipe->screen;
 485    const struct gl_renderbuffer *depthRb =
 486       fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 487    const struct gl_renderbuffer *stencilRb =
 488       fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 489    GLuint i;
 490
 491    if (stencilRb && depthRb && stencilRb != depthRb) {
 492       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 493       return;
 494    }
 495
 496    if (!st_validate_attachment(screen,
 497                                &fb->Attachment[BUFFER_DEPTH],
 498                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 499       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 500       return;
 501    }
 502    if (!st_validate_attachment(screen,
 503                                &fb->Attachment[BUFFER_STENCIL],
 504                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 505       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 506       return;
 507    }
 508    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 509       if (!st_validate_attachment(screen,
 510                                   &fb->Attachment[BUFFER_COLOR0 + i],
 511                                   PIPE_TEXTURE_USAGE_RENDER_TARGET)) {
 512          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 513          return;
 514       }
 515    }
 516 }
 517
 518
 519 /**
 520  * Copy back color buffer to front color buffer.
 521  */
 522 static void
 523 copy_back_to_front(struct st_context *st,
 524                    struct gl_framebuffer *fb,
 525                    gl_buffer_index frontIndex,
 526                    gl_buffer_index backIndex)
 527
 528 {
 529    struct st_framebuffer *stfb = (struct st_framebuffer *) fb;
 530    struct pipe_surface *surf_front, *surf_back;
 531
 532    (void) st_get_framebuffer_surface(stfb, frontIndex, &surf_front);
 533    (void) st_get_framebuffer_surface(stfb, backIndex, &surf_back);
 534
 535    if (surf_front && surf_back) {
 536       if (st->pipe->surface_copy) {
 537          st->pipe->surface_copy(st->pipe,
 538                                 surf_front, 0, 0,  /* dest */
 539                                 surf_back, 0, 0,   /* src */
 540                                 fb->Width, fb->Height);
 541       } else {
 542          util_surface_copy(st->pipe, FALSE,
 543                            surf_front, 0, 0,
 544                            surf_back, 0, 0,
 545                            fb->Width, fb->Height);
 546       }
 547    }
 548 }
 549
 550
 551 /**
 552  * Check if we're drawing into, or read from, a front color buffer.  If the
 553  * front buffer is missing, create it now.
 554  *
 555  * The back color buffer must exist since we'll use its format/samples info
 556  * for creating the front buffer.
 557  *
 558  * \param frontIndex  either BUFFER_FRONT_LEFT or BUFFER_FRONT_RIGHT
 559  * \param backIndex  either BUFFER_BACK_LEFT or BUFFER_BACK_RIGHT
 560  */
 561 static void
 562 check_create_front_buffer(GLcontext *ctx, struct gl_framebuffer *fb,
 563                           gl_buffer_index frontIndex,
 564                           gl_buffer_index backIndex)
 565 {
 566    if (fb->Attachment[frontIndex].Renderbuffer == NULL) {
 567       GLboolean create = GL_FALSE;
 568
 569       /* check if drawing to or reading from front buffer */
 570       if (fb->_ColorReadBufferIndex == frontIndex) {
 571          create = GL_TRUE;
 572       }
 573       else {
 574          GLuint b;
 575          for (b = 0; b < fb->_NumColorDrawBuffers; b++) {
 576             if (fb->_ColorDrawBufferIndexes[b] == frontIndex) {
 577                create = GL_TRUE;
 578                break;
 579             }
 580          }
 581       }
 582
 583       if (create) {
 584          struct st_renderbuffer *back;
 585          struct gl_renderbuffer *front;
 586          enum pipe_format colorFormat;
 587          uint samples;
 588
 589          if (0)
 590             _mesa_debug(ctx, "Allocate new front buffer\n");
 591
 592          /* get back renderbuffer info */
 593          back = st_renderbuffer(fb->Attachment[backIndex].Renderbuffer);
 594          colorFormat = back->format;
 595          samples = back->Base.NumSamples;
 596
 597          /* create front renderbuffer */
 598          front = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
 599          _mesa_add_renderbuffer(fb, frontIndex, front);
 600
 601          /* alloc texture/surface for new front buffer */
 602          front->AllocStorage(ctx, front, front->InternalFormat,
 603                              fb->Width, fb->Height);
 604
 605          /* initialize the front color buffer contents by copying
 606           * the back buffer.
 607           */
 608          copy_back_to_front(ctx->st, fb, frontIndex, backIndex);
 609       }
 610    }
 611 }
 612
 613
 614 /**
 615  * If front left/right color buffers are missing, create them now.
 616  */
 617 static void
 618 check_create_front_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 619 {
 620    /* check if we need to create the front left buffer now */
 621    check_create_front_buffer(ctx, fb, BUFFER_FRONT_LEFT, BUFFER_BACK_LEFT);
 622
 623    if (fb->Visual.stereoMode) {
 624       check_create_front_buffer(ctx, fb, BUFFER_FRONT_RIGHT, BUFFER_BACK_RIGHT);
 625    }
 626
 627    st_invalidate_state(ctx, _NEW_BUFFERS);
 628 }
 629
 630
 631 /**
 632  * Called via glDrawBuffer.
 633  */
 634 static void
 635 st_DrawBuffers(GLcontext *ctx, GLsizei count, const GLenum *buffers)
 636 {
 637    (void) count;
 638    (void) buffers;
 639    check_create_front_buffers(ctx, ctx->DrawBuffer);
 640 }
 641
 642
 643 /**
 644  * Called via glReadBuffer.
 645  */
 646 static void
 647 st_ReadBuffer(GLcontext *ctx, GLenum buffer)
 648 {
 649    (void) buffer;
 650    check_create_front_buffers(ctx, ctx->ReadBuffer);
 651 }
 652
 653
 654 void st_init_fbo_functions(struct dd_function_table *functions)
 655 {
 656    functions->NewFramebuffer = st_new_framebuffer;
 657    functions->NewRenderbuffer = st_new_renderbuffer;
 658    functions->BindFramebuffer = st_bind_framebuffer;
 659    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 660    functions->RenderTexture = st_render_texture;
 661    functions->FinishRenderTexture = st_finish_render_texture;
 662    functions->ValidateFramebuffer = st_validate_framebuffer;
 663    /* no longer needed by core Mesa, drivers handle resizes...
 664    functions->ResizeBuffers = st_resize_buffers;
 665    */
 666
 667    functions->DrawBuffers = st_DrawBuffers;
 668    functions->ReadBuffer = st_ReadBuffer;
 669 }