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.DataType = st_format_datatype(format);
  88
  89    strb->defined = GL_FALSE;  /* undefined contents now */
  90
  91    if (strb->software) {
  92       size_t size;
  93
  94       free(strb->data);
  95
  96       assert(strb->format != PIPE_FORMAT_NONE);
  97
  98       strb->stride = util_format_get_stride(strb->format, width);
  99       size = util_format_get_2d_size(strb->format, strb->stride, height);
 100
 101       strb->data = malloc(size);
 102
 103       return strb->data != NULL;
 104    }
 105    else {
 106       struct pipe_resource template;
 107
 108       /* Free the old surface and texture
 109        */
 110       pipe_surface_reference( &strb->surface, NULL );
 111       pipe_resource_reference( &strb->texture, NULL );
 112       pipe_sampler_view_reference(&strb->sampler_view, NULL);
 113
 114       /* Setup new texture template.
 115        */
 116       memset(&template, 0, sizeof(template));
 117       template.target = st->internal_target;
 118       template.format = format;
 119       template.width0 = width;
 120       template.height0 = height;
 121       template.depth0 = 1;
 122       template.array_size = 1;
 123       template.last_level = 0;
 124       template.nr_samples = rb->NumSamples;
 125       if (util_format_is_depth_or_stencil(format)) {
 126          template.bind = PIPE_BIND_DEPTH_STENCIL;
 127       }
 128       else {
 129          template.bind = (PIPE_BIND_DISPLAY_TARGET |
 130                           PIPE_BIND_RENDER_TARGET);
 131       }
 132
 133       strb->texture = screen->resource_create(screen, &template);
 134
 135       if (!strb->texture)
 136          return FALSE;
 137
 138       memset(&surf_tmpl, 0, sizeof(surf_tmpl));
 139       u_surface_default_template(&surf_tmpl, strb->texture, template.bind);
 140       strb->surface = pipe->create_surface(pipe,
 141                                            strb->texture,
 142                                            &surf_tmpl);
 143       if (strb->surface) {
 144          assert(strb->surface->texture);
 145          assert(strb->surface->format);
 146          assert(strb->surface->width == width);
 147          assert(strb->surface->height == height);
 148       }
 149
 150       return strb->surface != NULL;
 151    }
 152 }
 153
 154
 155 /**
 156  * gl_renderbuffer::Delete()
 157  */
 158 static void
 159 st_renderbuffer_delete(struct gl_renderbuffer *rb)
 160 {
 161    struct st_renderbuffer *strb = st_renderbuffer(rb);
 162    ASSERT(strb);
 163    pipe_surface_reference(&strb->surface, NULL);
 164    pipe_resource_reference(&strb->texture, NULL);
 165    pipe_sampler_view_reference(&strb->sampler_view, NULL);
 166    free(strb->data);
 167    free(strb);
 168 }
 169
 170
 171 /**
 172  * gl_renderbuffer::GetPointer()
 173  */
 174 static void *
 175 null_get_pointer(struct gl_context * 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(struct gl_context *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(struct gl_context *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_R8G8B8A8_UNORM:
 243    case PIPE_FORMAT_B8G8R8A8_UNORM:
 244    case PIPE_FORMAT_A8R8G8B8_UNORM:
 245    case PIPE_FORMAT_R8G8B8X8_UNORM:
 246    case PIPE_FORMAT_B8G8R8X8_UNORM:
 247    case PIPE_FORMAT_X8R8G8B8_UNORM:
 248    case PIPE_FORMAT_B5G5R5A1_UNORM:
 249    case PIPE_FORMAT_B4G4R4A4_UNORM:
 250    case PIPE_FORMAT_B5G6R5_UNORM:
 251       strb->Base.InternalFormat = GL_RGBA;
 252       break;
 253    case PIPE_FORMAT_Z16_UNORM:
 254       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 255       break;
 256    case PIPE_FORMAT_Z32_UNORM:
 257       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 258       break;
 259    case PIPE_FORMAT_Z24_UNORM_S8_USCALED:
 260    case PIPE_FORMAT_S8_USCALED_Z24_UNORM:
 261    case PIPE_FORMAT_Z24X8_UNORM:
 262    case PIPE_FORMAT_X8Z24_UNORM:
 263       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 264       break;
 265    case PIPE_FORMAT_S8_USCALED:
 266       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 267       break;
 268    case PIPE_FORMAT_R16G16B16A16_SNORM:
 269       strb->Base.InternalFormat = GL_RGBA16;
 270       break;
 271    case PIPE_FORMAT_R8_UNORM:
 272       strb->Base.InternalFormat = GL_R8;
 273       break;
 274    case PIPE_FORMAT_R8G8_UNORM:
 275       strb->Base.InternalFormat = GL_RG8;
 276       break;
 277    case PIPE_FORMAT_R16_UNORM:
 278       strb->Base.InternalFormat = GL_R16;
 279       break;
 280    case PIPE_FORMAT_R16G16_UNORM:
 281       strb->Base.InternalFormat = GL_RG16;
 282       break;
 283    default:
 284       _mesa_problem(NULL,
 285                     "Unexpected format in st_new_renderbuffer_fb");
 286       free(strb);
 287       return NULL;
 288    }
 289
 290    /* st-specific methods */
 291    strb->Base.Delete = st_renderbuffer_delete;
 292    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 293    strb->Base.GetPointer = null_get_pointer;
 294
 295    /* surface is allocated in st_renderbuffer_alloc_storage() */
 296    strb->surface = NULL;
 297
 298    return &strb->Base;
 299 }
 300
 301
 302
 303
 304 /**
 305  * Called via ctx->Driver.BindFramebufferEXT().
 306  */
 307 static void
 308 st_bind_framebuffer(struct gl_context *ctx, GLenum target,
 309                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 310 {
 311
 312 }
 313
 314 /**
 315  * Called by ctx->Driver.FramebufferRenderbuffer
 316  */
 317 static void
 318 st_framebuffer_renderbuffer(struct gl_context *ctx,
 319                             struct gl_framebuffer *fb,
 320                             GLenum attachment,
 321                             struct gl_renderbuffer *rb)
 322 {
 323    /* XXX no need for derivation? */
 324    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 325 }
 326
 327
 328 /**
 329  * Called by ctx->Driver.RenderTexture
 330  */
 331 static void
 332 st_render_texture(struct gl_context *ctx,
 333                   struct gl_framebuffer *fb,
 334                   struct gl_renderbuffer_attachment *att)
 335 {
 336    struct st_context *st = st_context(ctx);
 337    struct pipe_context *pipe = st->pipe;
 338    struct st_renderbuffer *strb;
 339    struct gl_renderbuffer *rb;
 340    struct pipe_resource *pt = st_get_texobj_resource(att->Texture);
 341    struct st_texture_object *stObj;
 342    const struct gl_texture_image *texImage;
 343    struct pipe_surface surf_tmpl;
 344
 345    /* When would this fail?  Perhaps assert? */
 346    if (!pt)
 347       return;
 348
 349    /* get pointer to texture image we're rendeing to */
 350    texImage = att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 351
 352    /* create new renderbuffer which wraps the texture image */
 353    rb = st_new_renderbuffer(ctx, 0);
 354    if (!rb) {
 355       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 356       return;
 357    }
 358
 359    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 360    assert(rb->RefCount == 1);
 361    rb->AllocStorage = NULL; /* should not get called */
 362    strb = st_renderbuffer(rb);
 363
 364    assert(strb->Base.RefCount > 0);
 365
 366    /* get the texture for the texture object */
 367    stObj = st_texture_object(att->Texture);
 368
 369    /* point renderbuffer at texobject */
 370    strb->rtt = stObj;
 371    strb->rtt_level = att->TextureLevel;
 372    strb->rtt_face = att->CubeMapFace;
 373    strb->rtt_slice = att->Zoffset;
 374
 375    rb->Width = texImage->Width2;
 376    rb->Height = texImage->Height2;
 377    rb->_BaseFormat = texImage->_BaseFormat;
 378    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 379
 380    /*printf("***** pipe texture %d x %d\n", pt->width0, pt->height0);*/
 381
 382    pipe_resource_reference( &strb->texture, pt );
 383
 384    pipe_surface_reference(&strb->surface, NULL);
 385
 386    pipe_sampler_view_reference(&strb->sampler_view,
 387                                st_get_texture_sampler_view(stObj, pipe));
 388
 389    assert(strb->rtt_level <= strb->texture->last_level);
 390
 391    /* new surface for rendering into the texture */
 392    memset(&surf_tmpl, 0, sizeof(surf_tmpl));
 393    surf_tmpl.format = ctx->Color.sRGBEnabled ? strb->texture->format : util_format_linear(strb->texture->format);
 394    surf_tmpl.usage = PIPE_BIND_RENDER_TARGET;
 395    surf_tmpl.u.tex.level = strb->rtt_level;
 396    surf_tmpl.u.tex.first_layer = strb->rtt_face + strb->rtt_slice;
 397    surf_tmpl.u.tex.last_layer = strb->rtt_face + strb->rtt_slice;
 398    strb->surface = pipe->create_surface(pipe,
 399                                         strb->texture,
 400                                         &surf_tmpl);
 401
 402    strb->format = pt->format;
 403
 404    strb->Base.Format = st_pipe_format_to_mesa_format(pt->format);
 405    strb->Base.DataType = st_format_datatype(pt->format);
 406
 407    /*
 408    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 409           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 410    */
 411
 412    /* Invalidate buffer state so that the pipe's framebuffer state
 413     * gets updated.
 414     * That's where the new renderbuffer (which we just created) gets
 415     * passed to the pipe as a (color/depth) render target.
 416     */
 417    st_invalidate_state(ctx, _NEW_BUFFERS);
 418 }
 419
 420
 421 /**
 422  * Called via ctx->Driver.FinishRenderTexture.
 423  */
 424 static void
 425 st_finish_render_texture(struct gl_context *ctx,
 426                          struct gl_renderbuffer_attachment *att)
 427 {
 428    struct st_context *st = st_context(ctx);
 429    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 430
 431    if (!strb)
 432       return;
 433
 434    st_flush(st, PIPE_FLUSH_RENDER_CACHE, NULL);
 435
 436    strb->rtt = NULL;
 437
 438    /*
 439    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 440    */
 441
 442    /* restore previous framebuffer state */
 443    st_invalidate_state(ctx, _NEW_BUFFERS);
 444 }
 445
 446
 447 /**
 448  * Validate a renderbuffer attachment for a particular set of bindings.
 449  */
 450 static GLboolean
 451 st_validate_attachment(struct gl_context *ctx,
 452                        struct pipe_screen *screen,
 453                        const struct gl_renderbuffer_attachment *att,
 454                        unsigned bindings)
 455 {
 456    const struct st_texture_object *stObj = st_texture_object(att->Texture);
 457    enum pipe_format format;
 458    gl_format texFormat;
 459
 460    /* Only validate texture attachments for now, since
 461     * st_renderbuffer_alloc_storage makes sure that
 462     * the format is supported.
 463     */
 464    if (att->Type != GL_TEXTURE)
 465       return GL_TRUE;
 466
 467    if (!stObj)
 468       return GL_FALSE;
 469
 470    format = stObj->pt->format;
 471    texFormat =
 472       stObj->base.Image[att->CubeMapFace][att->TextureLevel]->TexFormat;
 473
 474    /* If the encoding is sRGB and sRGB rendering cannot be enabled,
 475     * check for linear format support instead.
 476     * Later when we create a surface, we change the format to a linear one. */
 477    if (!ctx->Const.sRGBCapable &&
 478        _mesa_get_format_color_encoding(texFormat) == GL_SRGB) {
 479       const gl_format linearFormat = _mesa_get_srgb_format_linear(texFormat);
 480       format = st_mesa_format_to_pipe_format(linearFormat);
 481    }
 482
 483    return screen->is_format_supported(screen, format,
 484                                       PIPE_TEXTURE_2D,
 485                                       stObj->pt->nr_samples, bindings, 0);
 486 }
 487
 488
 489 /**
 490  * Check if two renderbuffer attachments name a combined depth/stencil
 491  * renderbuffer.
 492  */
 493 GLboolean
 494 st_is_depth_stencil_combined(const struct gl_renderbuffer_attachment *depth,
 495                              const struct gl_renderbuffer_attachment *stencil)
 496 {
 497    assert(depth && stencil);
 498
 499    if (depth->Type == stencil->Type) {
 500       if (depth->Type == GL_RENDERBUFFER_EXT &&
 501           depth->Renderbuffer == stencil->Renderbuffer)
 502          return GL_TRUE;
 503
 504       if (depth->Type == GL_TEXTURE &&
 505           depth->Texture == stencil->Texture)
 506          return GL_TRUE;
 507    }
 508
 509    return GL_FALSE;
 510 }
 511
 512
 513 /**
 514  * Check that the framebuffer configuration is valid in terms of what
 515  * the driver can support.
 516  *
 517  * For Gallium we only supports combined Z+stencil, not separate buffers.
 518  */
 519 static void
 520 st_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 521 {
 522    struct st_context *st = st_context(ctx);
 523    struct pipe_screen *screen = st->pipe->screen;
 524    const struct gl_renderbuffer_attachment *depth =
 525          &fb->Attachment[BUFFER_DEPTH];
 526    const struct gl_renderbuffer_attachment *stencil =
 527          &fb->Attachment[BUFFER_STENCIL];
 528    GLuint i;
 529
 530    if (depth->Type && stencil->Type && depth->Type != stencil->Type) {
 531       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 532       return;
 533    }
 534    if (depth->Type == GL_RENDERBUFFER_EXT &&
 535        stencil->Type == GL_RENDERBUFFER_EXT &&
 536        depth->Renderbuffer != stencil->Renderbuffer) {
 537       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 538       return;
 539    }
 540    if (depth->Type == GL_TEXTURE &&
 541        stencil->Type == GL_TEXTURE &&
 542        depth->Texture != stencil->Texture) {
 543       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 544       return;
 545    }
 546
 547    if (!st_validate_attachment(ctx,
 548                                screen,
 549                                depth,
 550                                PIPE_BIND_DEPTH_STENCIL)) {
 551       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 552       return;
 553    }
 554    if (!st_validate_attachment(ctx,
 555                                screen,
 556                                stencil,
 557                                PIPE_BIND_DEPTH_STENCIL)) {
 558       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 559       return;
 560    }
 561    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 562       if (!st_validate_attachment(ctx,
 563                                   screen,
 564                                   &fb->Attachment[BUFFER_COLOR0 + i],
 565                                   PIPE_BIND_RENDER_TARGET)) {
 566          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 567          return;
 568       }
 569    }
 570 }
 571
 572
 573 /**
 574  * Called via glDrawBuffer.
 575  */
 576 static void
 577 st_DrawBuffers(struct gl_context *ctx, GLsizei count, const GLenum *buffers)
 578 {
 579    struct st_context *st = st_context(ctx);
 580    struct gl_framebuffer *fb = ctx->DrawBuffer;
 581    GLuint i;
 582
 583    (void) count;
 584    (void) buffers;
 585
 586    /* add the renderbuffers on demand */
 587    for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
 588       gl_buffer_index idx = fb->_ColorDrawBufferIndexes[i];
 589       st_manager_add_color_renderbuffer(st, fb, idx);
 590    }
 591 }
 592
 593
 594 /**
 595  * Called via glReadBuffer.
 596  */
 597 static void
 598 st_ReadBuffer(struct gl_context *ctx, GLenum buffer)
 599 {
 600    struct st_context *st = st_context(ctx);
 601    struct gl_framebuffer *fb = ctx->ReadBuffer;
 602
 603    (void) buffer;
 604
 605    /* add the renderbuffer on demand */
 606    st_manager_add_color_renderbuffer(st, fb, fb->_ColorReadBufferIndex);
 607 }
 608
 609
 610 void st_init_fbo_functions(struct dd_function_table *functions)
 611 {
 612 #if FEATURE_EXT_framebuffer_object
 613    functions->NewFramebuffer = st_new_framebuffer;
 614    functions->NewRenderbuffer = st_new_renderbuffer;
 615    functions->BindFramebuffer = st_bind_framebuffer;
 616    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 617    functions->RenderTexture = st_render_texture;
 618    functions->FinishRenderTexture = st_finish_render_texture;
 619    functions->ValidateFramebuffer = st_validate_framebuffer;
 620 #endif
 621    /* no longer needed by core Mesa, drivers handle resizes...
 622    functions->ResizeBuffers = st_resize_buffers;
 623    */
 624
 625    functions->DrawBuffers = st_DrawBuffers;
 626    functions->ReadBuffer = st_ReadBuffer;
 627 }
 628
 629 /* XXX unused ? */
 630 struct pipe_sampler_view *
 631 st_get_renderbuffer_sampler_view(struct st_renderbuffer *rb,
 632                                  struct pipe_context *pipe)
 633 {
 634    if (!rb->sampler_view) {
 635       rb->sampler_view = st_create_texture_sampler_view(pipe, rb->texture);
 636    }
 637
 638    return rb->sampler_view;
 639 }