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/mfeatures.h"
  42 #include "main/renderbuffer.h"
  43
  44 #include "pipe/p_context.h"
  45 #include "pipe/p_defines.h"
  46 #include "pipe/p_screen.h"
  47 #include "st_context.h"
  48 #include "st_cb_fbo.h"
  49 #include "st_cb_flush.h"
  50 #include "st_format.h"
  51 #include "st_texture.h"
  52 #include "st_manager.h"
  53
  54 #include "util/u_format.h"
  55 #include "util/u_inlines.h"
  56 #include "util/u_surface.h"
  57
  58
  59 /**
  60  * gl_renderbuffer::AllocStorage()
  61  * This is called to allocate the original drawing surface, and
  62  * during window resize.
  63  */
  64 static GLboolean
  65 st_renderbuffer_alloc_storage(struct gl_context * ctx,
  66                               struct gl_renderbuffer *rb,
  67                               GLenum internalFormat,
  68                               GLuint width, GLuint height)
  69 {
  70    struct st_context *st = st_context(ctx);
  71    struct pipe_context *pipe = st->pipe;
  72    struct pipe_screen *screen = st->pipe->screen;
  73    struct st_renderbuffer *strb = st_renderbuffer(rb);
  74    enum pipe_format format;
  75    struct pipe_surface surf_tmpl;
  76
  77    if (strb->format != PIPE_FORMAT_NONE)
  78       format = strb->format;
  79    else
  80       format = st_choose_renderbuffer_format(screen, internalFormat,
  81                                              rb->NumSamples);
  82
  83    /* init renderbuffer fields */
  84    strb->Base.Width  = width;
  85    strb->Base.Height = height;
  86    strb->Base.Format = st_pipe_format_to_mesa_format(format);
  87    strb->Base._BaseFormat = _mesa_base_fbo_format(ctx, internalFormat);
  88    strb->Base.DataType = st_format_datatype(format);
  89
  90    strb->defined = GL_FALSE;  /* undefined contents now */
  91
  92    if (strb->software) {
  93       size_t size;
  94
  95       free(strb->data);
  96
  97       assert(strb->format != PIPE_FORMAT_NONE);
  98
  99       strb->stride = util_format_get_stride(strb->format, width);
 100       size = util_format_get_2d_size(strb->format, strb->stride, height);
 101
 102       strb->data = malloc(size);
 103
 104       return strb->data != NULL;
 105    }
 106    else {
 107       struct pipe_resource template;
 108
 109       /* Free the old surface and texture
 110        */
 111       pipe_surface_reference( &strb->surface, NULL );
 112       pipe_resource_reference( &strb->texture, NULL );
 113       pipe_sampler_view_reference(&strb->sampler_view, NULL);
 114
 115       /* Setup new texture template.
 116        */
 117       memset(&template, 0, sizeof(template));
 118       template.target = st->internal_target;
 119       template.format = format;
 120       template.width0 = width;
 121       template.height0 = height;
 122       template.depth0 = 1;
 123       template.array_size = 1;
 124       template.last_level = 0;
 125       template.nr_samples = rb->NumSamples;
 126       if (util_format_is_depth_or_stencil(format)) {
 127          template.bind = PIPE_BIND_DEPTH_STENCIL;
 128       }
 129       else {
 130          template.bind = (PIPE_BIND_DISPLAY_TARGET |
 131                           PIPE_BIND_RENDER_TARGET);
 132       }
 133
 134       strb->texture = screen->resource_create(screen, &template);
 135
 136       if (!strb->texture)
 137          return FALSE;
 138
 139       memset(&surf_tmpl, 0, sizeof(surf_tmpl));
 140       u_surface_default_template(&surf_tmpl, strb->texture, template.bind);
 141       strb->surface = pipe->create_surface(pipe,
 142                                            strb->texture,
 143                                            &surf_tmpl);
 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_resource_reference(&strb->texture, NULL);
 166    pipe_sampler_view_reference(&strb->sampler_view, NULL);
 167    free(strb->data);
 168    free(strb);
 169 }
 170
 171
 172 /**
 173  * gl_renderbuffer::GetPointer()
 174  */
 175 static void *
 176 null_get_pointer(struct gl_context * ctx, struct gl_renderbuffer *rb,
 177                  GLint x, GLint y)
 178 {
 179    /* By returning NULL we force all software rendering to go through
 180     * the span routines.
 181     */
 182 #if 0
 183    assert(0);  /* Should never get called with softpipe */
 184 #endif
 185    return NULL;
 186 }
 187
 188
 189 /**
 190  * Called via ctx->Driver.NewFramebuffer()
 191  */
 192 static struct gl_framebuffer *
 193 st_new_framebuffer(struct gl_context *ctx, GLuint name)
 194 {
 195    /* XXX not sure we need to subclass gl_framebuffer for pipe */
 196    return _mesa_new_framebuffer(ctx, name);
 197 }
 198
 199
 200 /**
 201  * Called via ctx->Driver.NewRenderbuffer()
 202  */
 203 static struct gl_renderbuffer *
 204 st_new_renderbuffer(struct gl_context *ctx, GLuint name)
 205 {
 206    struct st_renderbuffer *strb = ST_CALLOC_STRUCT(st_renderbuffer);
 207    if (strb) {
 208       _mesa_init_renderbuffer(&strb->Base, name);
 209       strb->Base.Delete = st_renderbuffer_delete;
 210       strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 211       strb->Base.GetPointer = null_get_pointer;
 212       strb->format = PIPE_FORMAT_NONE;
 213       return &strb->Base;
 214    }
 215    return NULL;
 216 }
 217
 218
 219 /**
 220  * Allocate a renderbuffer for a an on-screen window (not a user-created
 221  * renderbuffer).  The window system code determines the format.
 222  */
 223 struct gl_renderbuffer *
 224 st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw)
 225 {
 226    struct st_renderbuffer *strb;
 227
 228    strb = ST_CALLOC_STRUCT(st_renderbuffer);
 229    if (!strb) {
 230       _mesa_error(NULL, GL_OUT_OF_MEMORY, "creating renderbuffer");
 231       return NULL;
 232    }
 233
 234    _mesa_init_renderbuffer(&strb->Base, 0);
 235    strb->Base.ClassID = 0x4242; /* just a unique value */
 236    strb->Base.NumSamples = samples;
 237    strb->Base.Format = st_pipe_format_to_mesa_format(format);
 238    strb->Base._BaseFormat = _mesa_get_format_base_format(strb->Base.Format);
 239    strb->Base.DataType = st_format_datatype(format);
 240    strb->format = format;
 241    strb->software = sw;
 242
 243    switch (format) {
 244    case PIPE_FORMAT_R8G8B8A8_UNORM:
 245    case PIPE_FORMAT_B8G8R8A8_UNORM:
 246    case PIPE_FORMAT_A8R8G8B8_UNORM:
 247    case PIPE_FORMAT_R8G8B8X8_UNORM:
 248    case PIPE_FORMAT_B8G8R8X8_UNORM:
 249    case PIPE_FORMAT_X8R8G8B8_UNORM:
 250    case PIPE_FORMAT_B5G5R5A1_UNORM:
 251    case PIPE_FORMAT_B4G4R4A4_UNORM:
 252    case PIPE_FORMAT_B5G6R5_UNORM:
 253       strb->Base.InternalFormat = GL_RGBA;
 254       break;
 255    case PIPE_FORMAT_Z16_UNORM:
 256       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 257       break;
 258    case PIPE_FORMAT_Z32_UNORM:
 259       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 260       break;
 261    case PIPE_FORMAT_Z24_UNORM_S8_USCALED:
 262    case PIPE_FORMAT_S8_USCALED_Z24_UNORM:
 263    case PIPE_FORMAT_Z24X8_UNORM:
 264    case PIPE_FORMAT_X8Z24_UNORM:
 265       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 266       break;
 267    case PIPE_FORMAT_S8_USCALED:
 268       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 269       break;
 270    case PIPE_FORMAT_R16G16B16A16_SNORM:
 271       strb->Base.InternalFormat = GL_RGBA16;
 272       break;
 273    case PIPE_FORMAT_R8_UNORM:
 274       strb->Base.InternalFormat = GL_R8;
 275       break;
 276    case PIPE_FORMAT_R8G8_UNORM:
 277       strb->Base.InternalFormat = GL_RG8;
 278       break;
 279    case PIPE_FORMAT_R16_UNORM:
 280       strb->Base.InternalFormat = GL_R16;
 281       break;
 282    case PIPE_FORMAT_R16G16_UNORM:
 283       strb->Base.InternalFormat = GL_RG16;
 284       break;
 285    default:
 286       _mesa_problem(NULL,
 287                     "Unexpected format in st_new_renderbuffer_fb");
 288       free(strb);
 289       return NULL;
 290    }
 291
 292    /* st-specific methods */
 293    strb->Base.Delete = st_renderbuffer_delete;
 294    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 295    strb->Base.GetPointer = null_get_pointer;
 296
 297    /* surface is allocated in st_renderbuffer_alloc_storage() */
 298    strb->surface = NULL;
 299
 300    return &strb->Base;
 301 }
 302
 303
 304
 305
 306 /**
 307  * Called via ctx->Driver.BindFramebufferEXT().
 308  */
 309 static void
 310 st_bind_framebuffer(struct gl_context *ctx, GLenum target,
 311                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 312 {
 313
 314 }
 315
 316 /**
 317  * Called by ctx->Driver.FramebufferRenderbuffer
 318  */
 319 static void
 320 st_framebuffer_renderbuffer(struct gl_context *ctx,
 321                             struct gl_framebuffer *fb,
 322                             GLenum attachment,
 323                             struct gl_renderbuffer *rb)
 324 {
 325    /* XXX no need for derivation? */
 326    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 327 }
 328
 329
 330 /**
 331  * Called by ctx->Driver.RenderTexture
 332  */
 333 static void
 334 st_render_texture(struct gl_context *ctx,
 335                   struct gl_framebuffer *fb,
 336                   struct gl_renderbuffer_attachment *att)
 337 {
 338    struct st_context *st = st_context(ctx);
 339    struct pipe_context *pipe = st->pipe;
 340    struct st_renderbuffer *strb;
 341    struct gl_renderbuffer *rb;
 342    struct pipe_resource *pt = st_get_texobj_resource(att->Texture);
 343    struct st_texture_object *stObj;
 344    const struct gl_texture_image *texImage;
 345    struct pipe_surface surf_tmpl;
 346
 347    /* When would this fail?  Perhaps assert? */
 348    if (!pt)
 349       return;
 350
 351    /* get pointer to texture image we're rendeing to */
 352    texImage = att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 353
 354    /* create new renderbuffer which wraps the texture image */
 355    rb = st_new_renderbuffer(ctx, 0);
 356    if (!rb) {
 357       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 358       return;
 359    }
 360
 361    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 362    assert(rb->RefCount == 1);
 363    rb->AllocStorage = NULL; /* should not get called */
 364    strb = st_renderbuffer(rb);
 365
 366    assert(strb->Base.RefCount > 0);
 367
 368    /* get the texture for the texture object */
 369    stObj = st_texture_object(att->Texture);
 370
 371    /* point renderbuffer at texobject */
 372    strb->rtt = stObj;
 373    strb->rtt_level = att->TextureLevel;
 374    strb->rtt_face = att->CubeMapFace;
 375    strb->rtt_slice = att->Zoffset;
 376
 377    rb->Width = texImage->Width2;
 378    rb->Height = texImage->Height2;
 379    rb->_BaseFormat = texImage->_BaseFormat;
 380    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 381
 382    /*printf("***** pipe texture %d x %d\n", pt->width0, pt->height0);*/
 383
 384    pipe_resource_reference( &strb->texture, pt );
 385
 386    pipe_surface_reference(&strb->surface, NULL);
 387
 388    pipe_sampler_view_reference(&strb->sampler_view,
 389                                st_get_texture_sampler_view(stObj, pipe));
 390
 391    assert(strb->rtt_level <= strb->texture->last_level);
 392
 393    /* new surface for rendering into the texture */
 394    memset(&surf_tmpl, 0, sizeof(surf_tmpl));
 395    surf_tmpl.format = ctx->Color.sRGBEnabled ? strb->texture->format : util_format_linear(strb->texture->format);
 396    surf_tmpl.usage = PIPE_BIND_RENDER_TARGET;
 397    surf_tmpl.u.tex.level = strb->rtt_level;
 398    surf_tmpl.u.tex.first_layer = strb->rtt_face + strb->rtt_slice;
 399    surf_tmpl.u.tex.last_layer = strb->rtt_face + strb->rtt_slice;
 400    strb->surface = pipe->create_surface(pipe,
 401                                         strb->texture,
 402                                         &surf_tmpl);
 403
 404    strb->format = pt->format;
 405
 406    strb->Base.Format = st_pipe_format_to_mesa_format(pt->format);
 407    strb->Base.DataType = st_format_datatype(pt->format);
 408
 409    /*
 410    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 411           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 412    */
 413
 414    /* Invalidate buffer state so that the pipe's framebuffer state
 415     * gets updated.
 416     * That's where the new renderbuffer (which we just created) gets
 417     * passed to the pipe as a (color/depth) render target.
 418     */
 419    st_invalidate_state(ctx, _NEW_BUFFERS);
 420 }
 421
 422
 423 /**
 424  * Called via ctx->Driver.FinishRenderTexture.
 425  */
 426 static void
 427 st_finish_render_texture(struct gl_context *ctx,
 428                          struct gl_renderbuffer_attachment *att)
 429 {
 430    struct st_context *st = st_context(ctx);
 431    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 432
 433    if (!strb)
 434       return;
 435
 436    st_flush(st, PIPE_FLUSH_RENDER_CACHE, NULL);
 437
 438    strb->rtt = NULL;
 439
 440    /*
 441    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 442    */
 443
 444    /* restore previous framebuffer state */
 445    st_invalidate_state(ctx, _NEW_BUFFERS);
 446 }
 447
 448
 449 /**
 450  * Validate a renderbuffer attachment for a particular set of bindings.
 451  */
 452 static GLboolean
 453 st_validate_attachment(struct gl_context *ctx,
 454                        struct pipe_screen *screen,
 455                        const struct gl_renderbuffer_attachment *att,
 456                        unsigned bindings)
 457 {
 458    const struct st_texture_object *stObj = st_texture_object(att->Texture);
 459    enum pipe_format format;
 460    gl_format texFormat;
 461
 462    /* Only validate texture attachments for now, since
 463     * st_renderbuffer_alloc_storage makes sure that
 464     * the format is supported.
 465     */
 466    if (att->Type != GL_TEXTURE)
 467       return GL_TRUE;
 468
 469    if (!stObj)
 470       return GL_FALSE;
 471
 472    format = stObj->pt->format;
 473    texFormat =
 474       stObj->base.Image[att->CubeMapFace][att->TextureLevel]->TexFormat;
 475
 476    /* If the encoding is sRGB and sRGB rendering cannot be enabled,
 477     * check for linear format support instead.
 478     * Later when we create a surface, we change the format to a linear one. */
 479    if (!ctx->Const.sRGBCapable &&
 480        _mesa_get_format_color_encoding(texFormat) == GL_SRGB) {
 481       const gl_format linearFormat = _mesa_get_srgb_format_linear(texFormat);
 482       format = st_mesa_format_to_pipe_format(linearFormat);
 483    }
 484
 485    return screen->is_format_supported(screen, format,
 486                                       PIPE_TEXTURE_2D,
 487                                       stObj->pt->nr_samples, bindings, 0);
 488 }
 489
 490
 491 /**
 492  * Check if two renderbuffer attachments name a combined depth/stencil
 493  * renderbuffer.
 494  */
 495 GLboolean
 496 st_is_depth_stencil_combined(const struct gl_renderbuffer_attachment *depth,
 497                              const struct gl_renderbuffer_attachment *stencil)
 498 {
 499    assert(depth && stencil);
 500
 501    if (depth->Type == stencil->Type) {
 502       if (depth->Type == GL_RENDERBUFFER_EXT &&
 503           depth->Renderbuffer == stencil->Renderbuffer)
 504          return GL_TRUE;
 505
 506       if (depth->Type == GL_TEXTURE &&
 507           depth->Texture == stencil->Texture)
 508          return GL_TRUE;
 509    }
 510
 511    return GL_FALSE;
 512 }
 513
 514
 515 /**
 516  * Check that the framebuffer configuration is valid in terms of what
 517  * the driver can support.
 518  *
 519  * For Gallium we only supports combined Z+stencil, not separate buffers.
 520  */
 521 static void
 522 st_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 523 {
 524    struct st_context *st = st_context(ctx);
 525    struct pipe_screen *screen = st->pipe->screen;
 526    const struct gl_renderbuffer_attachment *depth =
 527          &fb->Attachment[BUFFER_DEPTH];
 528    const struct gl_renderbuffer_attachment *stencil =
 529          &fb->Attachment[BUFFER_STENCIL];
 530    GLuint i;
 531
 532    if (depth->Type && stencil->Type && depth->Type != stencil->Type) {
 533       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 534       return;
 535    }
 536    if (depth->Type == GL_RENDERBUFFER_EXT &&
 537        stencil->Type == GL_RENDERBUFFER_EXT &&
 538        depth->Renderbuffer != stencil->Renderbuffer) {
 539       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 540       return;
 541    }
 542    if (depth->Type == GL_TEXTURE &&
 543        stencil->Type == GL_TEXTURE &&
 544        depth->Texture != stencil->Texture) {
 545       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 546       return;
 547    }
 548
 549    if (!st_validate_attachment(ctx,
 550                                screen,
 551                                depth,
 552                                PIPE_BIND_DEPTH_STENCIL)) {
 553       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 554       return;
 555    }
 556    if (!st_validate_attachment(ctx,
 557                                screen,
 558                                stencil,
 559                                PIPE_BIND_DEPTH_STENCIL)) {
 560       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 561       return;
 562    }
 563    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 564       if (!st_validate_attachment(ctx,
 565                                   screen,
 566                                   &fb->Attachment[BUFFER_COLOR0 + i],
 567                                   PIPE_BIND_RENDER_TARGET)) {
 568          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 569          return;
 570       }
 571    }
 572 }
 573
 574
 575 /**
 576  * Called via glDrawBuffer.
 577  */
 578 static void
 579 st_DrawBuffers(struct gl_context *ctx, GLsizei count, const GLenum *buffers)
 580 {
 581    struct st_context *st = st_context(ctx);
 582    struct gl_framebuffer *fb = ctx->DrawBuffer;
 583    GLuint i;
 584
 585    (void) count;
 586    (void) buffers;
 587
 588    /* add the renderbuffers on demand */
 589    for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
 590       gl_buffer_index idx = fb->_ColorDrawBufferIndexes[i];
 591       st_manager_add_color_renderbuffer(st, fb, idx);
 592    }
 593 }
 594
 595
 596 /**
 597  * Called via glReadBuffer.
 598  */
 599 static void
 600 st_ReadBuffer(struct gl_context *ctx, GLenum buffer)
 601 {
 602    struct st_context *st = st_context(ctx);
 603    struct gl_framebuffer *fb = ctx->ReadBuffer;
 604
 605    (void) buffer;
 606
 607    /* add the renderbuffer on demand */
 608    st_manager_add_color_renderbuffer(st, fb, fb->_ColorReadBufferIndex);
 609 }
 610
 611
 612 void st_init_fbo_functions(struct dd_function_table *functions)
 613 {
 614 #if FEATURE_EXT_framebuffer_object
 615    functions->NewFramebuffer = st_new_framebuffer;
 616    functions->NewRenderbuffer = st_new_renderbuffer;
 617    functions->BindFramebuffer = st_bind_framebuffer;
 618    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 619    functions->RenderTexture = st_render_texture;
 620    functions->FinishRenderTexture = st_finish_render_texture;
 621    functions->ValidateFramebuffer = st_validate_framebuffer;
 622 #endif
 623    /* no longer needed by core Mesa, drivers handle resizes...
 624    functions->ResizeBuffers = st_resize_buffers;
 625    */
 626
 627    functions->DrawBuffers = st_DrawBuffers;
 628    functions->ReadBuffer = st_ReadBuffer;
 629 }
 630
 631 /* XXX unused ? */
 632 struct pipe_sampler_view *
 633 st_get_renderbuffer_sampler_view(struct st_renderbuffer *rb,
 634                                  struct pipe_context *pipe)
 635 {
 636    if (!rb->sampler_view) {
 637       rb->sampler_view = st_create_texture_sampler_view(pipe, rb->texture);
 638    }
 639
 640    return rb->sampler_view;
 641 }