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 #include "st_manager.h"
  52
  53 #include "util/u_format.h"
  54 #include "util/u_rect.h"
  55 #include "util/u_inlines.h"
  56
  57
  58 /**
  59  * gl_renderbuffer::AllocStorage()
  60  * This is called to allocate the original drawing surface, and
  61  * during window resize.
  62  */
  63 static GLboolean
  64 st_renderbuffer_alloc_storage(GLcontext * ctx, struct gl_renderbuffer *rb,
  65                               GLenum internalFormat,
  66                               GLuint width, GLuint height)
  67 {
  68    struct pipe_screen *screen = ctx->st->pipe->screen;
  69    struct st_renderbuffer *strb = st_renderbuffer(rb);
  70    enum pipe_format format;
  71
  72    if (strb->format != PIPE_FORMAT_NONE)
  73       format = strb->format;
  74    else
  75       format = st_choose_renderbuffer_format(screen, internalFormat);
  76
  77    /* init renderbuffer fields */
  78    strb->Base.Width  = width;
  79    strb->Base.Height = height;
  80    strb->Base.Format = st_pipe_format_to_mesa_format(format);
  81    strb->Base.DataType = st_format_datatype(format);
  82
  83    strb->defined = GL_FALSE;  /* undefined contents now */
  84
  85    if (strb->software) {
  86       size_t size;
  87
  88       free(strb->data);
  89
  90       assert(strb->format != PIPE_FORMAT_NONE);
  91
  92       strb->stride = util_format_get_stride(strb->format, width);
  93       size = util_format_get_2d_size(strb->format, strb->stride, height);
  94
  95       strb->data = malloc(size);
  96
  97       return strb->data != NULL;
  98    }
  99    else {
 100       struct pipe_texture template;
 101       unsigned surface_usage;
 102
 103       /* Free the old surface and texture
 104        */
 105       pipe_surface_reference( &strb->surface, NULL );
 106       pipe_texture_reference( &strb->texture, NULL );
 107
 108       /* Setup new texture template.
 109        */
 110       memset(&template, 0, sizeof(template));
 111       template.target = PIPE_TEXTURE_2D;
 112       template.format = format;
 113       template.width0 = width;
 114       template.height0 = height;
 115       template.depth0 = 1;
 116       template.last_level = 0;
 117       template.nr_samples = rb->NumSamples;
 118       if (util_format_is_depth_or_stencil(format)) {
 119          template.tex_usage = PIPE_TEXTURE_USAGE_DEPTH_STENCIL;
 120       }
 121       else {
 122          template.tex_usage = (PIPE_TEXTURE_USAGE_DISPLAY_TARGET |
 123                                PIPE_TEXTURE_USAGE_RENDER_TARGET);
 124       }
 125
 126       /* Probably need dedicated flags for surface usage too:
 127        */
 128       surface_usage = (PIPE_BUFFER_USAGE_GPU_READ |
 129                        PIPE_BUFFER_USAGE_GPU_WRITE);
 130 #if 0
 131                        PIPE_BUFFER_USAGE_CPU_READ |
 132                        PIPE_BUFFER_USAGE_CPU_WRITE);
 133 #endif
 134
 135       strb->texture = screen->texture_create(screen, &template);
 136
 137       if (!strb->texture)
 138          return FALSE;
 139
 140       strb->surface = screen->get_tex_surface(screen,
 141                                               strb->texture,
 142                                               0, 0, 0,
 143                                               surface_usage);
 144       if (strb->surface) {
 145          assert(strb->surface->texture);
 146          assert(strb->surface->format);
 147          assert(strb->surface->width == width);
 148          assert(strb->surface->height == height);
 149       }
 150
 151       return strb->surface != NULL;
 152    }
 153 }
 154
 155
 156 /**
 157  * gl_renderbuffer::Delete()
 158  */
 159 static void
 160 st_renderbuffer_delete(struct gl_renderbuffer *rb)
 161 {
 162    struct st_renderbuffer *strb = st_renderbuffer(rb);
 163    ASSERT(strb);
 164    pipe_surface_reference(&strb->surface, NULL);
 165    pipe_texture_reference(&strb->texture, NULL);
 166    free(strb->data);
 167    free(strb);
 168 }
 169
 170
 171 /**
 172  * gl_renderbuffer::GetPointer()
 173  */
 174 static void *
 175 null_get_pointer(GLcontext * ctx, struct gl_renderbuffer *rb,
 176                  GLint x, GLint y)
 177 {
 178    /* By returning NULL we force all software rendering to go through
 179     * the span routines.
 180     */
 181 #if 0
 182    assert(0);  /* Should never get called with softpipe */
 183 #endif
 184    return NULL;
 185 }
 186
 187
 188 /**
 189  * Called via ctx->Driver.NewFramebuffer()
 190  */
 191 static struct gl_framebuffer *
 192 st_new_framebuffer(GLcontext *ctx, GLuint name)
 193 {
 194    /* XXX not sure we need to subclass gl_framebuffer for pipe */
 195    return _mesa_new_framebuffer(ctx, name);
 196 }
 197
 198
 199 /**
 200  * Called via ctx->Driver.NewRenderbuffer()
 201  */
 202 static struct gl_renderbuffer *
 203 st_new_renderbuffer(GLcontext *ctx, GLuint name)
 204 {
 205    struct st_renderbuffer *strb = ST_CALLOC_STRUCT(st_renderbuffer);
 206    if (strb) {
 207       _mesa_init_renderbuffer(&strb->Base, name);
 208       strb->Base.Delete = st_renderbuffer_delete;
 209       strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 210       strb->Base.GetPointer = null_get_pointer;
 211       strb->format = PIPE_FORMAT_NONE;
 212       return &strb->Base;
 213    }
 214    return NULL;
 215 }
 216
 217
 218 /**
 219  * Allocate a renderbuffer for a an on-screen window (not a user-created
 220  * renderbuffer).  The window system code determines the format.
 221  */
 222 struct gl_renderbuffer *
 223 st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw)
 224 {
 225    struct st_renderbuffer *strb;
 226
 227    strb = ST_CALLOC_STRUCT(st_renderbuffer);
 228    if (!strb) {
 229       _mesa_error(NULL, GL_OUT_OF_MEMORY, "creating renderbuffer");
 230       return NULL;
 231    }
 232
 233    _mesa_init_renderbuffer(&strb->Base, 0);
 234    strb->Base.ClassID = 0x4242; /* just a unique value */
 235    strb->Base.NumSamples = samples;
 236    strb->Base.Format = st_pipe_format_to_mesa_format(format);
 237    strb->Base.DataType = st_format_datatype(format);
 238    strb->format = format;
 239    strb->software = sw;
 240
 241    switch (format) {
 242    case PIPE_FORMAT_B8G8R8A8_UNORM:
 243    case PIPE_FORMAT_A8R8G8B8_UNORM:
 244    case PIPE_FORMAT_B8G8R8X8_UNORM:
 245    case PIPE_FORMAT_X8R8G8B8_UNORM:
 246    case PIPE_FORMAT_B5G5R5A1_UNORM:
 247    case PIPE_FORMAT_B4G4R4A4_UNORM:
 248    case PIPE_FORMAT_B5G6R5_UNORM:
 249       strb->Base.InternalFormat = GL_RGBA;
 250       break;
 251    case PIPE_FORMAT_Z16_UNORM:
 252       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 253       break;
 254    case PIPE_FORMAT_Z32_UNORM:
 255       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 256       break;
 257    case PIPE_FORMAT_Z24S8_UNORM:
 258    case PIPE_FORMAT_S8Z24_UNORM:
 259    case PIPE_FORMAT_Z24X8_UNORM:
 260    case PIPE_FORMAT_X8Z24_UNORM:
 261       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 262       break;
 263    case PIPE_FORMAT_S8_UNORM:
 264       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 265       break;
 266    case PIPE_FORMAT_R16G16B16A16_SNORM:
 267       strb->Base.InternalFormat = GL_RGBA16;
 268       break;
 269    default:
 270       _mesa_problem(NULL,
 271                     "Unexpected format in st_new_renderbuffer_fb");
 272       free(strb);
 273       return NULL;
 274    }
 275
 276    /* st-specific methods */
 277    strb->Base.Delete = st_renderbuffer_delete;
 278    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 279    strb->Base.GetPointer = null_get_pointer;
 280
 281    /* surface is allocated in st_renderbuffer_alloc_storage() */
 282    strb->surface = NULL;
 283
 284    return &strb->Base;
 285 }
 286
 287
 288
 289
 290 /**
 291  * Called via ctx->Driver.BindFramebufferEXT().
 292  */
 293 static void
 294 st_bind_framebuffer(GLcontext *ctx, GLenum target,
 295                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 296 {
 297
 298 }
 299
 300 /**
 301  * Called by ctx->Driver.FramebufferRenderbuffer
 302  */
 303 static void
 304 st_framebuffer_renderbuffer(GLcontext *ctx,
 305                             struct gl_framebuffer *fb,
 306                             GLenum attachment,
 307                             struct gl_renderbuffer *rb)
 308 {
 309    /* XXX no need for derivation? */
 310    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 311 }
 312
 313
 314 /**
 315  * Called by ctx->Driver.RenderTexture
 316  */
 317 static void
 318 st_render_texture(GLcontext *ctx,
 319                   struct gl_framebuffer *fb,
 320                   struct gl_renderbuffer_attachment *att)
 321 {
 322    struct pipe_screen *screen = ctx->st->pipe->screen;
 323    struct st_renderbuffer *strb;
 324    struct gl_renderbuffer *rb;
 325    struct pipe_texture *pt = st_get_texobj_texture(att->Texture);
 326    struct st_texture_object *stObj;
 327    const struct gl_texture_image *texImage;
 328    GLint pt_level;
 329
 330    /* When would this fail?  Perhaps assert? */
 331    if (!pt)
 332       return;
 333
 334    /* The first gallium texture level = Mesa BaseLevel */
 335    pt_level = MAX2(0, (GLint) att->TextureLevel - att->Texture->BaseLevel);
 336    texImage = att->Texture->Image[att->CubeMapFace][pt_level];
 337
 338    /* create new renderbuffer which wraps the texture image */
 339    rb = st_new_renderbuffer(ctx, 0);
 340    if (!rb) {
 341       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 342       return;
 343    }
 344
 345    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 346    assert(rb->RefCount == 1);
 347    rb->AllocStorage = NULL; /* should not get called */
 348    strb = st_renderbuffer(rb);
 349
 350    assert(strb->Base.RefCount > 0);
 351
 352    /* get the texture for the texture object */
 353    stObj = st_texture_object(att->Texture);
 354
 355    /* point renderbuffer at texobject */
 356    strb->rtt = stObj;
 357    strb->rtt_level = pt_level;
 358    strb->rtt_face = att->CubeMapFace;
 359    strb->rtt_slice = att->Zoffset;
 360
 361    rb->Width = texImage->Width2;
 362    rb->Height = texImage->Height2;
 363    rb->_BaseFormat = texImage->_BaseFormat;
 364    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 365
 366    /*printf("***** pipe texture %d x %d\n", pt->width0, pt->height0);*/
 367
 368    pipe_texture_reference( &strb->texture, pt );
 369
 370    pipe_surface_reference(&strb->surface, NULL);
 371
 372    assert(strb->rtt_level <= strb->texture->last_level);
 373
 374    /* new surface for rendering into the texture */
 375    strb->surface = screen->get_tex_surface(screen,
 376                                            strb->texture,
 377                                            strb->rtt_face,
 378                                            strb->rtt_level,
 379                                            strb->rtt_slice,
 380                                            PIPE_BUFFER_USAGE_GPU_READ |
 381                                            PIPE_BUFFER_USAGE_GPU_WRITE);
 382
 383    strb->format = pt->format;
 384
 385    strb->Base.Format = st_pipe_format_to_mesa_format(pt->format);
 386    strb->Base.DataType = st_format_datatype(pt->format);
 387
 388    /*
 389    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 390           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 391    */
 392
 393    /* Invalidate buffer state so that the pipe's framebuffer state
 394     * gets updated.
 395     * That's where the new renderbuffer (which we just created) gets
 396     * passed to the pipe as a (color/depth) render target.
 397     */
 398    st_invalidate_state(ctx, _NEW_BUFFERS);
 399 }
 400
 401
 402 /**
 403  * Called via ctx->Driver.FinishRenderTexture.
 404  */
 405 static void
 406 st_finish_render_texture(GLcontext *ctx,
 407                          struct gl_renderbuffer_attachment *att)
 408 {
 409    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 410
 411    if (!strb)
 412       return;
 413
 414    st_flush( ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL );
 415
 416    strb->rtt = NULL;
 417
 418    /*
 419    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 420    */
 421
 422    /* restore previous framebuffer state */
 423    st_invalidate_state(ctx, _NEW_BUFFERS);
 424 }
 425
 426
 427 /**
 428  * Validate a renderbuffer attachment for a particular usage.
 429  */
 430
 431 static GLboolean
 432 st_validate_attachment(struct pipe_screen *screen,
 433                        const struct gl_renderbuffer_attachment *att,
 434                        GLuint usage)
 435 {
 436    const struct st_texture_object *stObj =
 437       st_texture_object(att->Texture);
 438
 439    /**
 440     * Only validate texture attachments for now, since
 441     * st_renderbuffer_alloc_storage makes sure that
 442     * the format is supported.
 443     */
 444
 445    if (att->Type != GL_TEXTURE)
 446       return GL_TRUE;
 447
 448    if (!stObj)
 449       return GL_FALSE;
 450
 451    return screen->is_format_supported(screen, stObj->pt->format,
 452                                       PIPE_TEXTURE_2D,
 453                                       usage, 0);
 454 }
 455
 456 /**
 457  * Check that the framebuffer configuration is valid in terms of what
 458  * the driver can support.
 459  *
 460  * For Gallium we only supports combined Z+stencil, not separate buffers.
 461  */
 462 static void
 463 st_validate_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 464 {
 465    struct pipe_screen *screen = ctx->st->pipe->screen;
 466    const struct gl_renderbuffer *depthRb =
 467       fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 468    const struct gl_renderbuffer *stencilRb =
 469       fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 470    GLuint i;
 471
 472    if (stencilRb && depthRb && stencilRb != depthRb) {
 473       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 474       return;
 475    }
 476
 477    if (!st_validate_attachment(screen,
 478                                &fb->Attachment[BUFFER_DEPTH],
 479                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 480       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 481       return;
 482    }
 483    if (!st_validate_attachment(screen,
 484                                &fb->Attachment[BUFFER_STENCIL],
 485                                PIPE_TEXTURE_USAGE_DEPTH_STENCIL)) {
 486       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 487       return;
 488    }
 489    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 490       if (!st_validate_attachment(screen,
 491                                   &fb->Attachment[BUFFER_COLOR0 + i],
 492                                   PIPE_TEXTURE_USAGE_RENDER_TARGET)) {
 493          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 494          return;
 495       }
 496    }
 497 }
 498
 499
 500 /**
 501  * Copy back color buffer to front color buffer.
 502  */
 503 static void
 504 copy_back_to_front(struct st_context *st,
 505                    struct gl_framebuffer *fb,
 506                    gl_buffer_index frontIndex,
 507                    gl_buffer_index backIndex)
 508
 509 {
 510    struct st_framebuffer *stfb = (struct st_framebuffer *) fb;
 511    struct pipe_surface *surf_front, *surf_back;
 512
 513    (void) st_get_framebuffer_surface(stfb, frontIndex, &surf_front);
 514    (void) st_get_framebuffer_surface(stfb, backIndex, &surf_back);
 515
 516    if (surf_front && surf_back) {
 517       if (st->pipe->surface_copy) {
 518          st->pipe->surface_copy(st->pipe,
 519                                 surf_front, 0, 0,  /* dest */
 520                                 surf_back, 0, 0,   /* src */
 521                                 fb->Width, fb->Height);
 522       } else {
 523          util_surface_copy(st->pipe, FALSE,
 524                            surf_front, 0, 0,
 525                            surf_back, 0, 0,
 526                            fb->Width, fb->Height);
 527       }
 528    }
 529 }
 530
 531
 532 /**
 533  * Check if we're drawing into, or read from, a front color buffer.  If the
 534  * front buffer is missing, create it now.
 535  *
 536  * The back color buffer must exist since we'll use its format/samples info
 537  * for creating the front buffer.
 538  *
 539  * \param frontIndex  either BUFFER_FRONT_LEFT or BUFFER_FRONT_RIGHT
 540  * \param backIndex  either BUFFER_BACK_LEFT or BUFFER_BACK_RIGHT
 541  */
 542 static void
 543 check_create_front_buffer(GLcontext *ctx, struct gl_framebuffer *fb,
 544                           gl_buffer_index frontIndex,
 545                           gl_buffer_index backIndex)
 546 {
 547    if (fb->Attachment[frontIndex].Renderbuffer == NULL) {
 548       GLboolean create = GL_FALSE;
 549
 550       /* check if drawing to or reading from front buffer */
 551       if (fb->_ColorReadBufferIndex == frontIndex) {
 552          create = GL_TRUE;
 553       }
 554       else {
 555          GLuint b;
 556          for (b = 0; b < fb->_NumColorDrawBuffers; b++) {
 557             if (fb->_ColorDrawBufferIndexes[b] == frontIndex) {
 558                create = GL_TRUE;
 559                break;
 560             }
 561          }
 562       }
 563
 564       if (create) {
 565          struct st_renderbuffer *back;
 566          struct gl_renderbuffer *front;
 567          enum pipe_format colorFormat;
 568          uint samples;
 569
 570          if (0)
 571             _mesa_debug(ctx, "Allocate new front buffer\n");
 572
 573          /* get back renderbuffer info */
 574          back = st_renderbuffer(fb->Attachment[backIndex].Renderbuffer);
 575          colorFormat = back->format;
 576          samples = back->Base.NumSamples;
 577
 578          /* create front renderbuffer */
 579          front = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
 580          _mesa_add_renderbuffer(fb, frontIndex, front);
 581
 582          /* alloc texture/surface for new front buffer */
 583          front->AllocStorage(ctx, front, front->InternalFormat,
 584                              fb->Width, fb->Height);
 585
 586          /* initialize the front color buffer contents by copying
 587           * the back buffer.
 588           */
 589          copy_back_to_front(ctx->st, fb, frontIndex, backIndex);
 590       }
 591    }
 592 }
 593
 594
 595 /**
 596  * If front left/right color buffers are missing, create them now.
 597  */
 598 static void
 599 check_create_front_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 600 {
 601    /* check if we need to create the front left buffer now */
 602    check_create_front_buffer(ctx, fb, BUFFER_FRONT_LEFT, BUFFER_BACK_LEFT);
 603
 604    if (fb->Visual.stereoMode) {
 605       check_create_front_buffer(ctx, fb, BUFFER_FRONT_RIGHT, BUFFER_BACK_RIGHT);
 606    }
 607
 608    st_invalidate_state(ctx, _NEW_BUFFERS);
 609 }
 610
 611
 612 /**
 613  * Called via glDrawBuffer.
 614  */
 615 static void
 616 st_DrawBuffers(GLcontext *ctx, GLsizei count, const GLenum *buffers)
 617 {
 618    GLframebuffer *fb = ctx->DrawBuffer;
 619    GLuint i;
 620
 621    (void) count;
 622    (void) buffers;
 623
 624    /* add the renderbuffers on demand */
 625    for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
 626       gl_buffer_index idx = fb->_ColorDrawBufferIndexes[i];
 627       st_manager_add_color_renderbuffer(ctx->st, fb, idx);
 628    }
 629
 630    check_create_front_buffers(ctx, ctx->DrawBuffer);
 631 }
 632
 633
 634 /**
 635  * Called via glReadBuffer.
 636  */
 637 static void
 638 st_ReadBuffer(GLcontext *ctx, GLenum buffer)
 639 {
 640    GLframebuffer *fb = ctx->ReadBuffer;
 641
 642    (void) buffer;
 643
 644    /* add the renderbuffer on demand */
 645    st_manager_add_color_renderbuffer(ctx->st, fb, fb->_ColorReadBufferIndex);
 646    check_create_front_buffers(ctx, fb);
 647 }
 648
 649
 650 void st_init_fbo_functions(struct dd_function_table *functions)
 651 {
 652    functions->NewFramebuffer = st_new_framebuffer;
 653    functions->NewRenderbuffer = st_new_renderbuffer;
 654    functions->BindFramebuffer = st_bind_framebuffer;
 655    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 656    functions->RenderTexture = st_render_texture;
 657    functions->FinishRenderTexture = st_finish_render_texture;
 658    functions->ValidateFramebuffer = st_validate_framebuffer;
 659    /* no longer needed by core Mesa, drivers handle resizes...
 660    functions->ResizeBuffers = st_resize_buffers;
 661    */
 662
 663    functions->DrawBuffers = st_DrawBuffers;
 664    functions->ReadBuffer = st_ReadBuffer;
 665 }