src/mesa/state_tracker/st_cb_clear.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  * Copyright 2009 VMware, Inc.  All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  21  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  22  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  23  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  24  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  25  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29  /*
  30   * Authors:
  31   *   Keith Whitwell <keith@tungstengraphics.com>
  32   *   Brian Paul
  33   *   Michel Dänzer
  34   */
  35
  36 #include "main/glheader.h"
  37 #include "main/accum.h"
  38 #include "main/formats.h"
  39 #include "main/macros.h"
  40 #include "program/prog_instruction.h"
  41 #include "st_context.h"
  42 #include "st_atom.h"
  43 #include "st_cb_clear.h"
  44 #include "st_cb_fbo.h"
  45 #include "st_format.h"
  46 #include "st_program.h"
  47
  48 #include "pipe/p_context.h"
  49 #include "pipe/p_shader_tokens.h"
  50 #include "pipe/p_state.h"
  51 #include "pipe/p_defines.h"
  52 #include "util/u_format.h"
  53 #include "util/u_inlines.h"
  54 #include "util/u_simple_shaders.h"
  55 #include "util/u_draw_quad.h"
  56
  57 #include "cso_cache/cso_context.h"
  58
  59
  60 /**
  61  * Do per-context initialization for glClear.
  62  */
  63 void
  64 st_init_clear(struct st_context *st)
  65 {
  66    struct pipe_screen *pscreen = st->pipe->screen;
  67
  68    memset(&st->clear, 0, sizeof(st->clear));
  69
  70    st->clear.raster.gl_rasterization_rules = 1;
  71    st->clear.enable_ds_separate = pscreen->get_param(pscreen, PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE);
  72 }
  73
  74
  75 /**
  76  * Free per-context state for glClear.
  77  */
  78 void
  79 st_destroy_clear(struct st_context *st)
  80 {
  81    if (st->clear.fs) {
  82       cso_delete_fragment_shader(st->cso_context, st->clear.fs);
  83       st->clear.fs = NULL;
  84    }
  85    if (st->clear.vs) {
  86       cso_delete_vertex_shader(st->cso_context, st->clear.vs);
  87       st->clear.vs = NULL;
  88    }
  89    if (st->clear.vbuf) {
  90       pipe_resource_reference(&st->clear.vbuf, NULL);
  91       st->clear.vbuf = NULL;
  92    }
  93 }
  94
  95
  96 /**
  97  * Helper function to set the fragment shaders.
  98  */
  99 static INLINE void
 100 set_fragment_shader(struct st_context *st)
 101 {
 102    if (!st->clear.fs)
 103       st->clear.fs = util_make_fragment_passthrough_shader(st->pipe);
 104
 105    cso_set_fragment_shader_handle(st->cso_context, st->clear.fs);
 106 }
 107
 108
 109 /**
 110  * Helper function to set the vertex shader.
 111  */
 112 static INLINE void
 113 set_vertex_shader(struct st_context *st)
 114 {
 115    /* vertex shader - still required to provide the linkage between
 116     * fragment shader input semantics and vertex_element/buffers.
 117     */
 118    if (!st->clear.vs)
 119    {
 120       const uint semantic_names[] = { TGSI_SEMANTIC_POSITION,
 121                                       TGSI_SEMANTIC_COLOR };
 122       const uint semantic_indexes[] = { 0, 0 };
 123       st->clear.vs = util_make_vertex_passthrough_shader(st->pipe, 2,
 124                                                          semantic_names,
 125                                                          semantic_indexes);
 126    }
 127
 128    cso_set_vertex_shader_handle(st->cso_context, st->clear.vs);
 129 }
 130
 131
 132 /**
 133  * Draw a screen-aligned quadrilateral.
 134  * Coords are clip coords with y=0=bottom.
 135  */
 136 static void
 137 draw_quad(struct st_context *st,
 138           float x0, float y0, float x1, float y1, GLfloat z,
 139           const union pipe_color_union *color)
 140 {
 141    struct pipe_context *pipe = st->pipe;
 142
 143    /* XXX: Need to improve buffer_write to allow NO_WAIT (as well as
 144     * no_flush) updates to buffers where we know there is no conflict
 145     * with previous data.  Currently using max_slots > 1 will cause
 146     * synchronous rendering if the driver flushes its command buffers
 147     * between one bitmap and the next.  Our flush hook below isn't
 148     * sufficient to catch this as the driver doesn't tell us when it
 149     * flushes its own command buffers.  Until this gets fixed, pay the
 150     * price of allocating a new buffer for each bitmap cache-flush to
 151     * avoid synchronous rendering.
 152     */
 153    const GLuint max_slots = 1; /* 1024 / sizeof(st->clear.vertices); */
 154    GLuint i;
 155
 156    if (st->clear.vbuf_slot >= max_slots) {
 157       pipe_resource_reference(&st->clear.vbuf, NULL);
 158       st->clear.vbuf_slot = 0;
 159    }
 160
 161    if (!st->clear.vbuf) {
 162       st->clear.vbuf = pipe_buffer_create(pipe->screen,
 163                                           PIPE_BIND_VERTEX_BUFFER,
 164                                           PIPE_USAGE_STREAM,
 165                                           max_slots * sizeof(st->clear.vertices));
 166    }
 167
 168    if (!st->clear.vbuf) {
 169       /* ran out of memory */
 170       return;
 171    }
 172
 173    /* positions */
 174    st->clear.vertices[0][0][0] = x0;
 175    st->clear.vertices[0][0][1] = y0;
 176
 177    st->clear.vertices[1][0][0] = x1;
 178    st->clear.vertices[1][0][1] = y0;
 179
 180    st->clear.vertices[2][0][0] = x1;
 181    st->clear.vertices[2][0][1] = y1;
 182
 183    st->clear.vertices[3][0][0] = x0;
 184    st->clear.vertices[3][0][1] = y1;
 185
 186    /* same for all verts: */
 187    for (i = 0; i < 4; i++) {
 188       st->clear.vertices[i][0][2] = z;
 189       st->clear.vertices[i][0][3] = 1.0;
 190       st->clear.vertices[i][1][0] = color->f[0];
 191       st->clear.vertices[i][1][1] = color->f[1];
 192       st->clear.vertices[i][1][2] = color->f[2];
 193       st->clear.vertices[i][1][3] = color->f[3];
 194    }
 195
 196    /* put vertex data into vbuf */
 197    pipe_buffer_write_nooverlap(st->pipe, st->clear.vbuf,
 198                                            st->clear.vbuf_slot
 199                                              * sizeof(st->clear.vertices),
 200                                            sizeof(st->clear.vertices),
 201                                            st->clear.vertices);
 202
 203    /* draw */
 204    util_draw_vertex_buffer(pipe,
 205                            st->cso_context,
 206                            st->clear.vbuf,
 207                            st->clear.vbuf_slot * sizeof(st->clear.vertices),
 208                            PIPE_PRIM_TRIANGLE_FAN,
 209                            4,  /* verts */
 210                            2); /* attribs/vert */
 211
 212    /* Increment slot */
 213    st->clear.vbuf_slot++;
 214 }
 215
 216
 217
 218 /**
 219  * Do glClear by drawing a quadrilateral.
 220  * The vertices of the quad will be computed from the
 221  * ctx->DrawBuffer->_X/Ymin/max fields.
 222  */
 223 static void
 224 clear_with_quad(struct gl_context *ctx,
 225                 GLboolean color, GLboolean depth, GLboolean stencil)
 226 {
 227    struct st_context *st = st_context(ctx);
 228    const struct gl_framebuffer *fb = ctx->DrawBuffer;
 229    const GLfloat fb_width = (GLfloat) fb->Width;
 230    const GLfloat fb_height = (GLfloat) fb->Height;
 231    const GLfloat x0 = (GLfloat) ctx->DrawBuffer->_Xmin / fb_width * 2.0f - 1.0f;
 232    const GLfloat x1 = (GLfloat) ctx->DrawBuffer->_Xmax / fb_width * 2.0f - 1.0f;
 233    const GLfloat y0 = (GLfloat) ctx->DrawBuffer->_Ymin / fb_height * 2.0f - 1.0f;
 234    const GLfloat y1 = (GLfloat) ctx->DrawBuffer->_Ymax / fb_height * 2.0f - 1.0f;
 235    union pipe_color_union clearColor;
 236
 237    /*
 238    printf("%s %s%s%s %f,%f %f,%f\n", __FUNCTION__,
 239           color ? "color, " : "",
 240           depth ? "depth, " : "",
 241           stencil ? "stencil" : "",
 242           x0, y0,
 243           x1, y1);
 244    */
 245
 246    cso_save_blend(st->cso_context);
 247    cso_save_stencil_ref(st->cso_context);
 248    cso_save_depth_stencil_alpha(st->cso_context);
 249    cso_save_rasterizer(st->cso_context);
 250    cso_save_viewport(st->cso_context);
 251    cso_save_clip(st->cso_context);
 252    cso_save_fragment_shader(st->cso_context);
 253    cso_save_stream_outputs(st->cso_context);
 254    cso_save_vertex_shader(st->cso_context);
 255    cso_save_geometry_shader(st->cso_context);
 256    cso_save_vertex_elements(st->cso_context);
 257    cso_save_vertex_buffers(st->cso_context);
 258
 259    /* blend state: RGBA masking */
 260    {
 261       struct pipe_blend_state blend;
 262       memset(&blend, 0, sizeof(blend));
 263       blend.rt[0].rgb_src_factor = PIPE_BLENDFACTOR_ONE;
 264       blend.rt[0].alpha_src_factor = PIPE_BLENDFACTOR_ONE;
 265       blend.rt[0].rgb_dst_factor = PIPE_BLENDFACTOR_ZERO;
 266       blend.rt[0].alpha_dst_factor = PIPE_BLENDFACTOR_ZERO;
 267       if (color) {
 268          if (ctx->Color.ColorMask[0][0])
 269             blend.rt[0].colormask |= PIPE_MASK_R;
 270          if (ctx->Color.ColorMask[0][1])
 271             blend.rt[0].colormask |= PIPE_MASK_G;
 272          if (ctx->Color.ColorMask[0][2])
 273             blend.rt[0].colormask |= PIPE_MASK_B;
 274          if (ctx->Color.ColorMask[0][3])
 275             blend.rt[0].colormask |= PIPE_MASK_A;
 276          if (st->ctx->Color.DitherFlag)
 277             blend.dither = 1;
 278       }
 279       cso_set_blend(st->cso_context, &blend);
 280    }
 281
 282    /* depth_stencil state: always pass/set to ref value */
 283    {
 284       struct pipe_depth_stencil_alpha_state depth_stencil;
 285       memset(&depth_stencil, 0, sizeof(depth_stencil));
 286       if (depth) {
 287          depth_stencil.depth.enabled = 1;
 288          depth_stencil.depth.writemask = 1;
 289          depth_stencil.depth.func = PIPE_FUNC_ALWAYS;
 290       }
 291
 292       if (stencil) {
 293          struct pipe_stencil_ref stencil_ref;
 294          memset(&stencil_ref, 0, sizeof(stencil_ref));
 295          depth_stencil.stencil[0].enabled = 1;
 296          depth_stencil.stencil[0].func = PIPE_FUNC_ALWAYS;
 297          depth_stencil.stencil[0].fail_op = PIPE_STENCIL_OP_REPLACE;
 298          depth_stencil.stencil[0].zpass_op = PIPE_STENCIL_OP_REPLACE;
 299          depth_stencil.stencil[0].zfail_op = PIPE_STENCIL_OP_REPLACE;
 300          depth_stencil.stencil[0].valuemask = 0xff;
 301          depth_stencil.stencil[0].writemask = ctx->Stencil.WriteMask[0] & 0xff;
 302          stencil_ref.ref_value[0] = ctx->Stencil.Clear;
 303          cso_set_stencil_ref(st->cso_context, &stencil_ref);
 304       }
 305
 306       cso_set_depth_stencil_alpha(st->cso_context, &depth_stencil);
 307    }
 308
 309    cso_set_vertex_elements(st->cso_context, 2, st->velems_util_draw);
 310    cso_set_stream_outputs(st->cso_context, 0, NULL, 0);
 311
 312    cso_set_rasterizer(st->cso_context, &st->clear.raster);
 313
 314    /* viewport state: viewport matching window dims */
 315    {
 316       const GLboolean invert = (st_fb_orientation(fb) == Y_0_TOP);
 317       struct pipe_viewport_state vp;
 318       vp.scale[0] = 0.5f * fb_width;
 319       vp.scale[1] = fb_height * (invert ? -0.5f : 0.5f);
 320       vp.scale[2] = 1.0f;
 321       vp.scale[3] = 1.0f;
 322       vp.translate[0] = 0.5f * fb_width;
 323       vp.translate[1] = 0.5f * fb_height;
 324       vp.translate[2] = 0.0f;
 325       vp.translate[3] = 0.0f;
 326       cso_set_viewport(st->cso_context, &vp);
 327    }
 328
 329    cso_set_clip(st->cso_context, &st->clear.clip);
 330    set_fragment_shader(st);
 331    set_vertex_shader(st);
 332    cso_set_geometry_shader_handle(st->cso_context, NULL);
 333
 334    if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 335       st_translate_color(ctx->Color.ClearColor.f,
 336                                ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 337                                clearColor.f);
 338    }
 339
 340    /* draw quad matching scissor rect */
 341    draw_quad(st, x0, y0, x1, y1, (GLfloat) ctx->Depth.Clear, &clearColor);
 342
 343    /* Restore pipe state */
 344    cso_restore_blend(st->cso_context);
 345    cso_restore_stencil_ref(st->cso_context);
 346    cso_restore_depth_stencil_alpha(st->cso_context);
 347    cso_restore_rasterizer(st->cso_context);
 348    cso_restore_viewport(st->cso_context);
 349    cso_restore_clip(st->cso_context);
 350    cso_restore_fragment_shader(st->cso_context);
 351    cso_restore_vertex_shader(st->cso_context);
 352    cso_restore_geometry_shader(st->cso_context);
 353    cso_restore_vertex_elements(st->cso_context);
 354    cso_restore_vertex_buffers(st->cso_context);
 355    cso_restore_stream_outputs(st->cso_context);
 356 }
 357
 358
 359 /**
 360  * Determine if we need to clear the depth buffer by drawing a quad.
 361  */
 362 static INLINE GLboolean
 363 check_clear_color_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 364 {
 365    if (ctx->Scissor.Enabled &&
 366        (ctx->Scissor.X != 0 ||
 367         ctx->Scissor.Y != 0 ||
 368         ctx->Scissor.Width < rb->Width ||
 369         ctx->Scissor.Height < rb->Height))
 370       return GL_TRUE;
 371
 372    if (!ctx->Color.ColorMask[0][0] ||
 373        !ctx->Color.ColorMask[0][1] ||
 374        !ctx->Color.ColorMask[0][2] ||
 375        !ctx->Color.ColorMask[0][3])
 376       return GL_TRUE;
 377
 378    return GL_FALSE;
 379 }
 380
 381
 382 /**
 383  * Determine if we need to clear the combiend depth/stencil buffer by
 384  * drawing a quad.
 385  */
 386 static INLINE GLboolean
 387 check_clear_depth_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 388 {
 389    const GLuint stencilMax = 0xff;
 390    GLboolean maskStencil
 391       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 392
 393    assert(rb->Format == MESA_FORMAT_S8 ||
 394           rb->Format == MESA_FORMAT_Z24_S8 ||
 395           rb->Format == MESA_FORMAT_S8_Z24 ||
 396           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 397
 398    if (ctx->Scissor.Enabled &&
 399        (ctx->Scissor.X != 0 ||
 400         ctx->Scissor.Y != 0 ||
 401         ctx->Scissor.Width < rb->Width ||
 402         ctx->Scissor.Height < rb->Height))
 403       return GL_TRUE;
 404
 405    if (maskStencil)
 406       return GL_TRUE;
 407
 408    return GL_FALSE;
 409 }
 410
 411
 412 /**
 413  * Determine if we need to clear the depth buffer by drawing a quad.
 414  */
 415 static INLINE GLboolean
 416 check_clear_depth_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 417                             boolean ds_separate)
 418 {
 419    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 420    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 421
 422    if (ctx->Scissor.Enabled &&
 423        (ctx->Scissor.X != 0 ||
 424         ctx->Scissor.Y != 0 ||
 425         ctx->Scissor.Width < rb->Width ||
 426         ctx->Scissor.Height < rb->Height))
 427       return GL_TRUE;
 428
 429    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.stencilBits > 0)
 430       return GL_TRUE;
 431
 432    return GL_FALSE;
 433 }
 434
 435
 436 /**
 437  * Determine if we need to clear the stencil buffer by drawing a quad.
 438  */
 439 static INLINE GLboolean
 440 check_clear_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 441                               boolean ds_separate)
 442 {
 443    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 444    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 445    const GLuint stencilMax = 0xff;
 446    const GLboolean maskStencil
 447       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 448
 449    assert(rb->Format == MESA_FORMAT_S8 ||
 450           rb->Format == MESA_FORMAT_Z24_S8 ||
 451           rb->Format == MESA_FORMAT_S8_Z24 ||
 452           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 453
 454    if (maskStencil)
 455       return GL_TRUE;
 456
 457    if (ctx->Scissor.Enabled &&
 458        (ctx->Scissor.X != 0 ||
 459         ctx->Scissor.Y != 0 ||
 460         ctx->Scissor.Width < rb->Width ||
 461         ctx->Scissor.Height < rb->Height))
 462       return GL_TRUE;
 463
 464    /* This is correct, but it is necessary to look at the depth clear
 465     * value held in the surface when it comes time to issue the clear,
 466     * rather than taking depth and stencil clear values from the
 467     * current state.
 468     */
 469    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.depthBits > 0)
 470       return GL_TRUE;
 471
 472    return GL_FALSE;
 473 }
 474
 475
 476
 477 /**
 478  * Called when we need to flush.
 479  */
 480 void
 481 st_flush_clear(struct st_context *st)
 482 {
 483    /* Release vertex buffer to avoid synchronous rendering if we were
 484     * to map it in the next frame.
 485     */
 486    pipe_resource_reference(&st->clear.vbuf, NULL);
 487    st->clear.vbuf_slot = 0;
 488 }
 489
 490
 491
 492 /**
 493  * Called via ctx->Driver.Clear()
 494  */
 495 static void
 496 st_Clear(struct gl_context *ctx, GLbitfield mask)
 497 {
 498    static const GLbitfield BUFFER_BITS_DS
 499       = (BUFFER_BIT_DEPTH | BUFFER_BIT_STENCIL);
 500    struct st_context *st = st_context(ctx);
 501    struct gl_renderbuffer *depthRb
 502       = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 503    struct gl_renderbuffer *stencilRb
 504       = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 505    GLbitfield quad_buffers = 0x0;
 506    GLbitfield clear_buffers = 0x0;
 507    GLuint i;
 508
 509    /* This makes sure the pipe has the latest scissor, etc values */
 510    st_validate_state( st );
 511
 512    if (mask & BUFFER_BITS_COLOR) {
 513       for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
 514          GLuint b = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
 515
 516          if (mask & (1 << b)) {
 517             struct gl_renderbuffer *rb
 518                = ctx->DrawBuffer->Attachment[b].Renderbuffer;
 519             struct st_renderbuffer *strb = st_renderbuffer(rb);
 520
 521             if (!strb || !strb->surface)
 522                continue;
 523
 524             if (check_clear_color_with_quad( ctx, rb ))
 525                quad_buffers |= PIPE_CLEAR_COLOR;
 526             else
 527                clear_buffers |= PIPE_CLEAR_COLOR;
 528          }
 529       }
 530    }
 531
 532    if ((mask & BUFFER_BITS_DS) == BUFFER_BITS_DS && depthRb == stencilRb) {
 533       /* clearing combined depth + stencil */
 534       struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 535
 536       if (strb->surface) {
 537          if (check_clear_depth_stencil_with_quad(ctx, depthRb))
 538             quad_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 539          else
 540             clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 541       }
 542    }
 543    else {
 544       /* separate depth/stencil clears */
 545       /* I don't think truly separate buffers are actually possible in gallium or hw? */
 546       if (mask & BUFFER_BIT_DEPTH) {
 547          struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 548
 549          if (strb->surface) {
 550             if (check_clear_depth_with_quad(ctx, depthRb,
 551                                             st->clear.enable_ds_separate))
 552                quad_buffers |= PIPE_CLEAR_DEPTH;
 553             else
 554                clear_buffers |= PIPE_CLEAR_DEPTH;
 555          }
 556       }
 557       if (mask & BUFFER_BIT_STENCIL) {
 558          struct st_renderbuffer *strb = st_renderbuffer(stencilRb);
 559
 560          if (strb->surface) {
 561             if (check_clear_stencil_with_quad(ctx, stencilRb,
 562                                               st->clear.enable_ds_separate))
 563                quad_buffers |= PIPE_CLEAR_STENCIL;
 564             else
 565                clear_buffers |= PIPE_CLEAR_STENCIL;
 566          }
 567       }
 568    }
 569
 570    /*
 571     * If we're going to use clear_with_quad() for any reason, use it for
 572     * everything possible.
 573     */
 574    if (quad_buffers) {
 575       quad_buffers |= clear_buffers;
 576       clear_with_quad(ctx,
 577                       quad_buffers & PIPE_CLEAR_COLOR,
 578                       quad_buffers & PIPE_CLEAR_DEPTH,
 579                       quad_buffers & PIPE_CLEAR_STENCIL);
 580    } else if (clear_buffers) {
 581       /* driver cannot know it can clear everything if the buffer
 582        * is a combined depth/stencil buffer but this wasn't actually
 583        * required from the visual. Hence fix this up to avoid potential
 584        * read-modify-write in the driver.
 585        */
 586       union pipe_color_union clearColor;
 587
 588       if ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) &&
 589           ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) != PIPE_CLEAR_DEPTHSTENCIL) &&
 590           (depthRb == stencilRb) &&
 591           (ctx->DrawBuffer->Visual.depthBits == 0 ||
 592            ctx->DrawBuffer->Visual.stencilBits == 0))
 593          clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 594
 595       if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 596          st_translate_color(ctx->Color.ClearColor.f,
 597                             ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 598                             clearColor.f);
 599       }
 600
 601       st->pipe->clear(st->pipe, clear_buffers, &clearColor,
 602                       ctx->Depth.Clear, ctx->Stencil.Clear);
 603    }
 604    if (mask & BUFFER_BIT_ACCUM)
 605       _mesa_clear_accum_buffer(ctx);
 606 }
 607
 608
 609 void
 610 st_init_clear_functions(struct dd_function_table *functions)
 611 {
 612    functions->Clear = st_Clear;
 613 }