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_inlines.h"
  55
  56
  57 /**
  58  * gl_renderbuffer::AllocStorage()
  59  * This is called to allocate the original drawing surface, and
  60  * during window resize.
  61  */
  62 static GLboolean
  63 st_renderbuffer_alloc_storage(GLcontext * ctx, struct gl_renderbuffer *rb,
  64                               GLenum internalFormat,
  65                               GLuint width, GLuint height)
  66 {
  67    struct pipe_screen *screen = ctx->st->pipe->screen;
  68    struct st_renderbuffer *strb = st_renderbuffer(rb);
  69    enum pipe_format format;
  70
  71    if (strb->format != PIPE_FORMAT_NONE)
  72       format = strb->format;
  73    else
  74       format = st_choose_renderbuffer_format(screen, internalFormat);
  75
  76    /* init renderbuffer fields */
  77    strb->Base.Width  = width;
  78    strb->Base.Height = height;
  79    strb->Base.Format = st_pipe_format_to_mesa_format(format);
  80    strb->Base.DataType = st_format_datatype(format);
  81
  82    strb->defined = GL_FALSE;  /* undefined contents now */
  83
  84    if (strb->software) {
  85       size_t size;
  86
  87       free(strb->data);
  88
  89       assert(strb->format != PIPE_FORMAT_NONE);
  90
  91       strb->stride = util_format_get_stride(strb->format, width);
  92       size = util_format_get_2d_size(strb->format, strb->stride, height);
  93
  94       strb->data = malloc(size);
  95
  96       return strb->data != NULL;
  97    }
  98    else {
  99       struct pipe_resource template;
 100
 101       /* Free the old surface and texture
 102        */
 103       pipe_surface_reference( &strb->surface, NULL );
 104       pipe_resource_reference( &strb->texture, NULL );
 105       pipe_sampler_view_reference(&strb->sampler_view, NULL);
 106
 107       /* Setup new texture template.
 108        */
 109       memset(&template, 0, sizeof(template));
 110       template.target = PIPE_TEXTURE_2D;
 111       template.format = format;
 112       template.width0 = width;
 113       template.height0 = height;
 114       template.depth0 = 1;
 115       template.last_level = 0;
 116       template.nr_samples = rb->NumSamples;
 117       if (util_format_is_depth_or_stencil(format)) {
 118          template.bind = PIPE_BIND_DEPTH_STENCIL;
 119       }
 120       else {
 121          template.bind = (PIPE_BIND_DISPLAY_TARGET |
 122                           PIPE_BIND_RENDER_TARGET);
 123       }
 124
 125       strb->texture = screen->resource_create(screen, &template);
 126
 127       if (!strb->texture)
 128          return FALSE;
 129
 130       strb->surface = screen->get_tex_surface(screen,
 131                                               strb->texture,
 132                                               0, 0, 0,
 133                                               template.bind);
 134       if (strb->surface) {
 135          assert(strb->surface->texture);
 136          assert(strb->surface->format);
 137          assert(strb->surface->width == width);
 138          assert(strb->surface->height == height);
 139       }
 140
 141       return strb->surface != NULL;
 142    }
 143 }
 144
 145
 146 /**
 147  * gl_renderbuffer::Delete()
 148  */
 149 static void
 150 st_renderbuffer_delete(struct gl_renderbuffer *rb)
 151 {
 152    struct st_renderbuffer *strb = st_renderbuffer(rb);
 153    ASSERT(strb);
 154    pipe_surface_reference(&strb->surface, NULL);
 155    pipe_resource_reference(&strb->texture, NULL);
 156    pipe_sampler_view_reference(&strb->sampler_view, NULL);
 157    free(strb->data);
 158    free(strb);
 159 }
 160
 161
 162 /**
 163  * gl_renderbuffer::GetPointer()
 164  */
 165 static void *
 166 null_get_pointer(GLcontext * ctx, struct gl_renderbuffer *rb,
 167                  GLint x, GLint y)
 168 {
 169    /* By returning NULL we force all software rendering to go through
 170     * the span routines.
 171     */
 172 #if 0
 173    assert(0);  /* Should never get called with softpipe */
 174 #endif
 175    return NULL;
 176 }
 177
 178
 179 /**
 180  * Called via ctx->Driver.NewFramebuffer()
 181  */
 182 static struct gl_framebuffer *
 183 st_new_framebuffer(GLcontext *ctx, GLuint name)
 184 {
 185    /* XXX not sure we need to subclass gl_framebuffer for pipe */
 186    return _mesa_new_framebuffer(ctx, name);
 187 }
 188
 189
 190 /**
 191  * Called via ctx->Driver.NewRenderbuffer()
 192  */
 193 static struct gl_renderbuffer *
 194 st_new_renderbuffer(GLcontext *ctx, GLuint name)
 195 {
 196    struct st_renderbuffer *strb = ST_CALLOC_STRUCT(st_renderbuffer);
 197    if (strb) {
 198       _mesa_init_renderbuffer(&strb->Base, name);
 199       strb->Base.Delete = st_renderbuffer_delete;
 200       strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 201       strb->Base.GetPointer = null_get_pointer;
 202       strb->format = PIPE_FORMAT_NONE;
 203       return &strb->Base;
 204    }
 205    return NULL;
 206 }
 207
 208
 209 /**
 210  * Allocate a renderbuffer for a an on-screen window (not a user-created
 211  * renderbuffer).  The window system code determines the format.
 212  */
 213 struct gl_renderbuffer *
 214 st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw)
 215 {
 216    struct st_renderbuffer *strb;
 217
 218    strb = ST_CALLOC_STRUCT(st_renderbuffer);
 219    if (!strb) {
 220       _mesa_error(NULL, GL_OUT_OF_MEMORY, "creating renderbuffer");
 221       return NULL;
 222    }
 223
 224    _mesa_init_renderbuffer(&strb->Base, 0);
 225    strb->Base.ClassID = 0x4242; /* just a unique value */
 226    strb->Base.NumSamples = samples;
 227    strb->Base.Format = st_pipe_format_to_mesa_format(format);
 228    strb->Base.DataType = st_format_datatype(format);
 229    strb->format = format;
 230    strb->software = sw;
 231
 232    switch (format) {
 233    case PIPE_FORMAT_B8G8R8A8_UNORM:
 234    case PIPE_FORMAT_A8R8G8B8_UNORM:
 235    case PIPE_FORMAT_B8G8R8X8_UNORM:
 236    case PIPE_FORMAT_X8R8G8B8_UNORM:
 237    case PIPE_FORMAT_B5G5R5A1_UNORM:
 238    case PIPE_FORMAT_B4G4R4A4_UNORM:
 239    case PIPE_FORMAT_B5G6R5_UNORM:
 240       strb->Base.InternalFormat = GL_RGBA;
 241       break;
 242    case PIPE_FORMAT_Z16_UNORM:
 243       strb->Base.InternalFormat = GL_DEPTH_COMPONENT16;
 244       break;
 245    case PIPE_FORMAT_Z32_UNORM:
 246       strb->Base.InternalFormat = GL_DEPTH_COMPONENT32;
 247       break;
 248    case PIPE_FORMAT_Z24_UNORM_S8_USCALED:
 249    case PIPE_FORMAT_S8_USCALED_Z24_UNORM:
 250    case PIPE_FORMAT_Z24X8_UNORM:
 251    case PIPE_FORMAT_X8Z24_UNORM:
 252       strb->Base.InternalFormat = GL_DEPTH24_STENCIL8_EXT;
 253       break;
 254    case PIPE_FORMAT_S8_USCALED:
 255       strb->Base.InternalFormat = GL_STENCIL_INDEX8_EXT;
 256       break;
 257    case PIPE_FORMAT_R16G16B16A16_SNORM:
 258       strb->Base.InternalFormat = GL_RGBA16;
 259       break;
 260    default:
 261       _mesa_problem(NULL,
 262                     "Unexpected format in st_new_renderbuffer_fb");
 263       free(strb);
 264       return NULL;
 265    }
 266
 267    /* st-specific methods */
 268    strb->Base.Delete = st_renderbuffer_delete;
 269    strb->Base.AllocStorage = st_renderbuffer_alloc_storage;
 270    strb->Base.GetPointer = null_get_pointer;
 271
 272    /* surface is allocated in st_renderbuffer_alloc_storage() */
 273    strb->surface = NULL;
 274
 275    return &strb->Base;
 276 }
 277
 278
 279
 280
 281 /**
 282  * Called via ctx->Driver.BindFramebufferEXT().
 283  */
 284 static void
 285 st_bind_framebuffer(GLcontext *ctx, GLenum target,
 286                     struct gl_framebuffer *fb, struct gl_framebuffer *fbread)
 287 {
 288
 289 }
 290
 291 /**
 292  * Called by ctx->Driver.FramebufferRenderbuffer
 293  */
 294 static void
 295 st_framebuffer_renderbuffer(GLcontext *ctx,
 296                             struct gl_framebuffer *fb,
 297                             GLenum attachment,
 298                             struct gl_renderbuffer *rb)
 299 {
 300    /* XXX no need for derivation? */
 301    _mesa_framebuffer_renderbuffer(ctx, fb, attachment, rb);
 302 }
 303
 304
 305 /**
 306  * Called by ctx->Driver.RenderTexture
 307  */
 308 static void
 309 st_render_texture(GLcontext *ctx,
 310                   struct gl_framebuffer *fb,
 311                   struct gl_renderbuffer_attachment *att)
 312 {
 313    struct pipe_screen *screen = ctx->st->pipe->screen;
 314    struct st_renderbuffer *strb;
 315    struct gl_renderbuffer *rb;
 316    struct pipe_resource *pt = st_get_texobj_texture(att->Texture);
 317    struct st_texture_object *stObj;
 318    const struct gl_texture_image *texImage;
 319    GLint pt_level;
 320
 321    /* When would this fail?  Perhaps assert? */
 322    if (!pt)
 323       return;
 324
 325    /* The first gallium texture level = Mesa BaseLevel */
 326    pt_level = MAX2(0, (GLint) att->TextureLevel - att->Texture->BaseLevel);
 327    texImage = att->Texture->Image[att->CubeMapFace][pt_level];
 328
 329    /* create new renderbuffer which wraps the texture image */
 330    rb = st_new_renderbuffer(ctx, 0);
 331    if (!rb) {
 332       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
 333       return;
 334    }
 335
 336    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
 337    assert(rb->RefCount == 1);
 338    rb->AllocStorage = NULL; /* should not get called */
 339    strb = st_renderbuffer(rb);
 340
 341    assert(strb->Base.RefCount > 0);
 342
 343    /* get the texture for the texture object */
 344    stObj = st_texture_object(att->Texture);
 345
 346    /* point renderbuffer at texobject */
 347    strb->rtt = stObj;
 348    strb->rtt_level = pt_level;
 349    strb->rtt_face = att->CubeMapFace;
 350    strb->rtt_slice = att->Zoffset;
 351
 352    rb->Width = texImage->Width2;
 353    rb->Height = texImage->Height2;
 354    rb->_BaseFormat = texImage->_BaseFormat;
 355    /*printf("***** render to texture level %d: %d x %d\n", att->TextureLevel, rb->Width, rb->Height);*/
 356
 357    /*printf("***** pipe texture %d x %d\n", pt->width0, pt->height0);*/
 358
 359    pipe_resource_reference( &strb->texture, pt );
 360
 361    pipe_surface_reference(&strb->surface, NULL);
 362
 363    pipe_sampler_view_reference(&strb->sampler_view, st_get_stobj_sampler_view(stObj));
 364
 365    assert(strb->rtt_level <= strb->texture->last_level);
 366
 367    /* new surface for rendering into the texture */
 368    strb->surface = screen->get_tex_surface(screen,
 369                                            strb->texture,
 370                                            strb->rtt_face,
 371                                            strb->rtt_level,
 372                                            strb->rtt_slice,
 373                                            PIPE_BIND_RENDER_TARGET);
 374
 375    strb->format = pt->format;
 376
 377    strb->Base.Format = st_pipe_format_to_mesa_format(pt->format);
 378    strb->Base.DataType = st_format_datatype(pt->format);
 379
 380    /*
 381    printf("RENDER TO TEXTURE obj=%p pt=%p surf=%p  %d x %d\n",
 382           att->Texture, pt, strb->surface, rb->Width, rb->Height);
 383    */
 384
 385    /* Invalidate buffer state so that the pipe's framebuffer state
 386     * gets updated.
 387     * That's where the new renderbuffer (which we just created) gets
 388     * passed to the pipe as a (color/depth) render target.
 389     */
 390    st_invalidate_state(ctx, _NEW_BUFFERS);
 391 }
 392
 393
 394 /**
 395  * Called via ctx->Driver.FinishRenderTexture.
 396  */
 397 static void
 398 st_finish_render_texture(GLcontext *ctx,
 399                          struct gl_renderbuffer_attachment *att)
 400 {
 401    struct st_renderbuffer *strb = st_renderbuffer(att->Renderbuffer);
 402
 403    if (!strb)
 404       return;
 405
 406    st_flush( ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL );
 407
 408    strb->rtt = NULL;
 409
 410    /*
 411    printf("FINISH RENDER TO TEXTURE surf=%p\n", strb->surface);
 412    */
 413
 414    /* restore previous framebuffer state */
 415    st_invalidate_state(ctx, _NEW_BUFFERS);
 416 }
 417
 418
 419 /**
 420  * Validate a renderbuffer attachment for a particular usage.
 421  */
 422
 423 static GLboolean
 424 st_validate_attachment(struct pipe_screen *screen,
 425                        const struct gl_renderbuffer_attachment *att,
 426                        GLuint usage)
 427 {
 428    const struct st_texture_object *stObj =
 429       st_texture_object(att->Texture);
 430
 431    /**
 432     * Only validate texture attachments for now, since
 433     * st_renderbuffer_alloc_storage makes sure that
 434     * the format is supported.
 435     */
 436
 437    if (att->Type != GL_TEXTURE)
 438       return GL_TRUE;
 439
 440    if (!stObj)
 441       return GL_FALSE;
 442
 443    return screen->is_format_supported(screen, stObj->pt->format,
 444                                       PIPE_TEXTURE_2D,
 445                                       usage, 0);
 446 }
 447
 448 /**
 449  * Check that the framebuffer configuration is valid in terms of what
 450  * the driver can support.
 451  *
 452  * For Gallium we only supports combined Z+stencil, not separate buffers.
 453  */
 454 static void
 455 st_validate_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 456 {
 457    struct pipe_screen *screen = ctx->st->pipe->screen;
 458    const struct gl_renderbuffer *depthRb =
 459       fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 460    const struct gl_renderbuffer *stencilRb =
 461       fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 462    GLuint i;
 463
 464    if (stencilRb && depthRb && stencilRb != depthRb) {
 465       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 466       return;
 467    }
 468
 469    if (!st_validate_attachment(screen,
 470                                &fb->Attachment[BUFFER_DEPTH],
 471                                PIPE_BIND_DEPTH_STENCIL)) {
 472       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 473       return;
 474    }
 475    if (!st_validate_attachment(screen,
 476                                &fb->Attachment[BUFFER_STENCIL],
 477                                PIPE_BIND_DEPTH_STENCIL)) {
 478       fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 479       return;
 480    }
 481    for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 482       if (!st_validate_attachment(screen,
 483                                   &fb->Attachment[BUFFER_COLOR0 + i],
 484                                   PIPE_BIND_RENDER_TARGET)) {
 485          fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
 486          return;
 487       }
 488    }
 489 }
 490
 491
 492 /**
 493  * Copy back color buffer to front color buffer.
 494  */
 495 static void
 496 copy_back_to_front(struct st_context *st,
 497                    struct gl_framebuffer *fb,
 498                    gl_buffer_index frontIndex,
 499                    gl_buffer_index backIndex)
 500
 501 {
 502    struct st_framebuffer *stfb = (struct st_framebuffer *) fb;
 503    struct pipe_surface *surf_front, *surf_back;
 504
 505    (void) st_get_framebuffer_surface(stfb, frontIndex, &surf_front);
 506    (void) st_get_framebuffer_surface(stfb, backIndex, &surf_back);
 507
 508    if (surf_front && surf_back) {
 509       st->pipe->surface_copy(st->pipe,
 510                              surf_front, 0, 0,  /* dest */
 511                              surf_back, 0, 0,   /* src */
 512                              fb->Width, fb->Height);
 513    }
 514 }
 515
 516
 517 /**
 518  * Check if we're drawing into, or read from, a front color buffer.  If the
 519  * front buffer is missing, create it now.
 520  *
 521  * The back color buffer must exist since we'll use its format/samples info
 522  * for creating the front buffer.
 523  *
 524  * \param frontIndex  either BUFFER_FRONT_LEFT or BUFFER_FRONT_RIGHT
 525  * \param backIndex  either BUFFER_BACK_LEFT or BUFFER_BACK_RIGHT
 526  */
 527 static void
 528 check_create_front_buffer(GLcontext *ctx, struct gl_framebuffer *fb,
 529                           gl_buffer_index frontIndex,
 530                           gl_buffer_index backIndex)
 531 {
 532    if (fb->Attachment[frontIndex].Renderbuffer == NULL) {
 533       GLboolean create = GL_FALSE;
 534
 535       /* check if drawing to or reading from front buffer */
 536       if (fb->_ColorReadBufferIndex == frontIndex) {
 537          create = GL_TRUE;
 538       }
 539       else {
 540          GLuint b;
 541          for (b = 0; b < fb->_NumColorDrawBuffers; b++) {
 542             if (fb->_ColorDrawBufferIndexes[b] == frontIndex) {
 543                create = GL_TRUE;
 544                break;
 545             }
 546          }
 547       }
 548
 549       if (create) {
 550          struct st_renderbuffer *back;
 551          struct gl_renderbuffer *front;
 552          enum pipe_format colorFormat;
 553          uint samples;
 554
 555          if (0)
 556             _mesa_debug(ctx, "Allocate new front buffer\n");
 557
 558          /* get back renderbuffer info */
 559          back = st_renderbuffer(fb->Attachment[backIndex].Renderbuffer);
 560          colorFormat = back->format;
 561          samples = back->Base.NumSamples;
 562
 563          /* create front renderbuffer */
 564          front = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
 565          _mesa_add_renderbuffer(fb, frontIndex, front);
 566
 567          /* alloc texture/surface for new front buffer */
 568          front->AllocStorage(ctx, front, front->InternalFormat,
 569                              fb->Width, fb->Height);
 570
 571          /* initialize the front color buffer contents by copying
 572           * the back buffer.
 573           */
 574          copy_back_to_front(ctx->st, fb, frontIndex, backIndex);
 575       }
 576    }
 577 }
 578
 579
 580 /**
 581  * If front left/right color buffers are missing, create them now.
 582  */
 583 static void
 584 check_create_front_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 585 {
 586    /* check if we need to create the front left buffer now */
 587    check_create_front_buffer(ctx, fb, BUFFER_FRONT_LEFT, BUFFER_BACK_LEFT);
 588
 589    if (fb->Visual.stereoMode) {
 590       check_create_front_buffer(ctx, fb, BUFFER_FRONT_RIGHT, BUFFER_BACK_RIGHT);
 591    }
 592
 593    st_invalidate_state(ctx, _NEW_BUFFERS);
 594 }
 595
 596
 597 /**
 598  * Called via glDrawBuffer.
 599  */
 600 static void
 601 st_DrawBuffers(GLcontext *ctx, GLsizei count, const GLenum *buffers)
 602 {
 603    GLframebuffer *fb = ctx->DrawBuffer;
 604    GLuint i;
 605
 606    (void) count;
 607    (void) buffers;
 608
 609    /* add the renderbuffers on demand */
 610    for (i = 0; i < fb->_NumColorDrawBuffers; i++) {
 611       gl_buffer_index idx = fb->_ColorDrawBufferIndexes[i];
 612       st_manager_add_color_renderbuffer(ctx->st, fb, idx);
 613    }
 614
 615    check_create_front_buffers(ctx, ctx->DrawBuffer);
 616 }
 617
 618
 619 /**
 620  * Called via glReadBuffer.
 621  */
 622 static void
 623 st_ReadBuffer(GLcontext *ctx, GLenum buffer)
 624 {
 625    GLframebuffer *fb = ctx->ReadBuffer;
 626
 627    (void) buffer;
 628
 629    /* add the renderbuffer on demand */
 630    st_manager_add_color_renderbuffer(ctx->st, fb, fb->_ColorReadBufferIndex);
 631    check_create_front_buffers(ctx, fb);
 632 }
 633
 634
 635 void st_init_fbo_functions(struct dd_function_table *functions)
 636 {
 637    functions->NewFramebuffer = st_new_framebuffer;
 638    functions->NewRenderbuffer = st_new_renderbuffer;
 639    functions->BindFramebuffer = st_bind_framebuffer;
 640    functions->FramebufferRenderbuffer = st_framebuffer_renderbuffer;
 641    functions->RenderTexture = st_render_texture;
 642    functions->FinishRenderTexture = st_finish_render_texture;
 643    functions->ValidateFramebuffer = st_validate_framebuffer;
 644    /* no longer needed by core Mesa, drivers handle resizes...
 645    functions->ResizeBuffers = st_resize_buffers;
 646    */
 647
 648    functions->DrawBuffers = st_DrawBuffers;
 649    functions->ReadBuffer = st_ReadBuffer;
 650 }
 651
 652 struct pipe_sampler_view *
 653 st_renderbuffer_get_sampler_view(struct st_renderbuffer *rb,
 654                                  struct pipe_context *pipe)
 655 {
 656    if (!rb->sampler_view) {
 657       rb->sampler_view = st_sampler_view_from_texture(pipe, rb->texture);
 658    }
 659
 660    return rb->sampler_view;
 661 }