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/formats.h"
  38 #include "main/macros.h"
  39 #include "program/prog_instruction.h"
  40 #include "st_context.h"
  41 #include "st_atom.h"
  42 #include "st_cb_accum.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    /* positions */
 169    st->clear.vertices[0][0][0] = x0;
 170    st->clear.vertices[0][0][1] = y0;
 171
 172    st->clear.vertices[1][0][0] = x1;
 173    st->clear.vertices[1][0][1] = y0;
 174
 175    st->clear.vertices[2][0][0] = x1;
 176    st->clear.vertices[2][0][1] = y1;
 177
 178    st->clear.vertices[3][0][0] = x0;
 179    st->clear.vertices[3][0][1] = y1;
 180
 181    /* same for all verts: */
 182    for (i = 0; i < 4; i++) {
 183       st->clear.vertices[i][0][2] = z;
 184       st->clear.vertices[i][0][3] = 1.0;
 185       st->clear.vertices[i][1][0] = color->f[0];
 186       st->clear.vertices[i][1][1] = color->f[1];
 187       st->clear.vertices[i][1][2] = color->f[2];
 188       st->clear.vertices[i][1][3] = color->f[3];
 189    }
 190
 191    /* put vertex data into vbuf */
 192    pipe_buffer_write_nooverlap(st->pipe, st->clear.vbuf,
 193                                            st->clear.vbuf_slot
 194                                              * sizeof(st->clear.vertices),
 195                                            sizeof(st->clear.vertices),
 196                                            st->clear.vertices);
 197
 198    /* draw */
 199    util_draw_vertex_buffer(pipe,
 200                            st->cso_context,
 201                            st->clear.vbuf,
 202                            st->clear.vbuf_slot * sizeof(st->clear.vertices),
 203                            PIPE_PRIM_TRIANGLE_FAN,
 204                            4,  /* verts */
 205                            2); /* attribs/vert */
 206
 207    /* Increment slot */
 208    st->clear.vbuf_slot++;
 209 }
 210
 211
 212
 213 /**
 214  * Do glClear by drawing a quadrilateral.
 215  * The vertices of the quad will be computed from the
 216  * ctx->DrawBuffer->_X/Ymin/max fields.
 217  */
 218 static void
 219 clear_with_quad(struct gl_context *ctx,
 220                 GLboolean color, GLboolean depth, GLboolean stencil)
 221 {
 222    struct st_context *st = st_context(ctx);
 223    const struct gl_framebuffer *fb = ctx->DrawBuffer;
 224    const GLfloat fb_width = (GLfloat) fb->Width;
 225    const GLfloat fb_height = (GLfloat) fb->Height;
 226    const GLfloat x0 = (GLfloat) ctx->DrawBuffer->_Xmin / fb_width * 2.0f - 1.0f;
 227    const GLfloat x1 = (GLfloat) ctx->DrawBuffer->_Xmax / fb_width * 2.0f - 1.0f;
 228    const GLfloat y0 = (GLfloat) ctx->DrawBuffer->_Ymin / fb_height * 2.0f - 1.0f;
 229    const GLfloat y1 = (GLfloat) ctx->DrawBuffer->_Ymax / fb_height * 2.0f - 1.0f;
 230    union pipe_color_union clearColor;
 231
 232    /*
 233    printf("%s %s%s%s %f,%f %f,%f\n", __FUNCTION__,
 234           color ? "color, " : "",
 235           depth ? "depth, " : "",
 236           stencil ? "stencil" : "",
 237           x0, y0,
 238           x1, y1);
 239    */
 240
 241    cso_save_blend(st->cso_context);
 242    cso_save_stencil_ref(st->cso_context);
 243    cso_save_depth_stencil_alpha(st->cso_context);
 244    cso_save_rasterizer(st->cso_context);
 245    cso_save_viewport(st->cso_context);
 246    cso_save_clip(st->cso_context);
 247    cso_save_fragment_shader(st->cso_context);
 248    cso_save_vertex_shader(st->cso_context);
 249    cso_save_geometry_shader(st->cso_context);
 250    cso_save_vertex_elements(st->cso_context);
 251    cso_save_vertex_buffers(st->cso_context);
 252
 253    /* blend state: RGBA masking */
 254    {
 255       struct pipe_blend_state blend;
 256       memset(&blend, 0, sizeof(blend));
 257       blend.rt[0].rgb_src_factor = PIPE_BLENDFACTOR_ONE;
 258       blend.rt[0].alpha_src_factor = PIPE_BLENDFACTOR_ONE;
 259       blend.rt[0].rgb_dst_factor = PIPE_BLENDFACTOR_ZERO;
 260       blend.rt[0].alpha_dst_factor = PIPE_BLENDFACTOR_ZERO;
 261       if (color) {
 262          if (ctx->Color.ColorMask[0][0])
 263             blend.rt[0].colormask |= PIPE_MASK_R;
 264          if (ctx->Color.ColorMask[0][1])
 265             blend.rt[0].colormask |= PIPE_MASK_G;
 266          if (ctx->Color.ColorMask[0][2])
 267             blend.rt[0].colormask |= PIPE_MASK_B;
 268          if (ctx->Color.ColorMask[0][3])
 269             blend.rt[0].colormask |= PIPE_MASK_A;
 270          if (st->ctx->Color.DitherFlag)
 271             blend.dither = 1;
 272       }
 273       cso_set_blend(st->cso_context, &blend);
 274    }
 275
 276    /* depth_stencil state: always pass/set to ref value */
 277    {
 278       struct pipe_depth_stencil_alpha_state depth_stencil;
 279       memset(&depth_stencil, 0, sizeof(depth_stencil));
 280       if (depth) {
 281          depth_stencil.depth.enabled = 1;
 282          depth_stencil.depth.writemask = 1;
 283          depth_stencil.depth.func = PIPE_FUNC_ALWAYS;
 284       }
 285
 286       if (stencil) {
 287          struct pipe_stencil_ref stencil_ref;
 288          memset(&stencil_ref, 0, sizeof(stencil_ref));
 289          depth_stencil.stencil[0].enabled = 1;
 290          depth_stencil.stencil[0].func = PIPE_FUNC_ALWAYS;
 291          depth_stencil.stencil[0].fail_op = PIPE_STENCIL_OP_REPLACE;
 292          depth_stencil.stencil[0].zpass_op = PIPE_STENCIL_OP_REPLACE;
 293          depth_stencil.stencil[0].zfail_op = PIPE_STENCIL_OP_REPLACE;
 294          depth_stencil.stencil[0].valuemask = 0xff;
 295          depth_stencil.stencil[0].writemask = ctx->Stencil.WriteMask[0] & 0xff;
 296          stencil_ref.ref_value[0] = ctx->Stencil.Clear;
 297          cso_set_stencil_ref(st->cso_context, &stencil_ref);
 298       }
 299
 300       cso_set_depth_stencil_alpha(st->cso_context, &depth_stencil);
 301    }
 302
 303    cso_set_vertex_elements(st->cso_context, 2, st->velems_util_draw);
 304
 305    cso_set_rasterizer(st->cso_context, &st->clear.raster);
 306
 307    /* viewport state: viewport matching window dims */
 308    {
 309       const GLboolean invert = (st_fb_orientation(fb) == Y_0_TOP);
 310       struct pipe_viewport_state vp;
 311       vp.scale[0] = 0.5f * fb_width;
 312       vp.scale[1] = fb_height * (invert ? -0.5f : 0.5f);
 313       vp.scale[2] = 1.0f;
 314       vp.scale[3] = 1.0f;
 315       vp.translate[0] = 0.5f * fb_width;
 316       vp.translate[1] = 0.5f * fb_height;
 317       vp.translate[2] = 0.0f;
 318       vp.translate[3] = 0.0f;
 319       cso_set_viewport(st->cso_context, &vp);
 320    }
 321
 322    cso_set_clip(st->cso_context, &st->clear.clip);
 323    set_fragment_shader(st);
 324    set_vertex_shader(st);
 325    cso_set_geometry_shader_handle(st->cso_context, NULL);
 326
 327    if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 328       st_translate_color(ctx->Color.ClearColor.f,
 329                                ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 330                                clearColor.f);
 331    }
 332
 333    /* draw quad matching scissor rect */
 334    draw_quad(st, x0, y0, x1, y1, (GLfloat) ctx->Depth.Clear, &clearColor);
 335
 336    /* Restore pipe state */
 337    cso_restore_blend(st->cso_context);
 338    cso_restore_stencil_ref(st->cso_context);
 339    cso_restore_depth_stencil_alpha(st->cso_context);
 340    cso_restore_rasterizer(st->cso_context);
 341    cso_restore_viewport(st->cso_context);
 342    cso_restore_clip(st->cso_context);
 343    cso_restore_fragment_shader(st->cso_context);
 344    cso_restore_vertex_shader(st->cso_context);
 345    cso_restore_geometry_shader(st->cso_context);
 346    cso_restore_vertex_elements(st->cso_context);
 347    cso_restore_vertex_buffers(st->cso_context);
 348 }
 349
 350
 351 /**
 352  * Determine if we need to clear the depth buffer by drawing a quad.
 353  */
 354 static INLINE GLboolean
 355 check_clear_color_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 356 {
 357    if (ctx->Scissor.Enabled &&
 358        (ctx->Scissor.X != 0 ||
 359         ctx->Scissor.Y != 0 ||
 360         ctx->Scissor.Width < rb->Width ||
 361         ctx->Scissor.Height < rb->Height))
 362       return GL_TRUE;
 363
 364    if (!ctx->Color.ColorMask[0][0] ||
 365        !ctx->Color.ColorMask[0][1] ||
 366        !ctx->Color.ColorMask[0][2] ||
 367        !ctx->Color.ColorMask[0][3])
 368       return GL_TRUE;
 369
 370    return GL_FALSE;
 371 }
 372
 373
 374 /**
 375  * Determine if we need to clear the combiend depth/stencil buffer by
 376  * drawing a quad.
 377  */
 378 static INLINE GLboolean
 379 check_clear_depth_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 380 {
 381    const GLuint stencilMax = 0xff;
 382    GLboolean maskStencil
 383       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 384
 385    assert(rb->Format == MESA_FORMAT_S8 ||
 386           rb->Format == MESA_FORMAT_Z24_S8 ||
 387           rb->Format == MESA_FORMAT_S8_Z24 ||
 388           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 389
 390    if (ctx->Scissor.Enabled &&
 391        (ctx->Scissor.X != 0 ||
 392         ctx->Scissor.Y != 0 ||
 393         ctx->Scissor.Width < rb->Width ||
 394         ctx->Scissor.Height < rb->Height))
 395       return GL_TRUE;
 396
 397    if (maskStencil)
 398       return GL_TRUE;
 399
 400    return GL_FALSE;
 401 }
 402
 403
 404 /**
 405  * Determine if we need to clear the depth buffer by drawing a quad.
 406  */
 407 static INLINE GLboolean
 408 check_clear_depth_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 409                             boolean ds_separate)
 410 {
 411    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 412    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 413
 414    if (ctx->Scissor.Enabled &&
 415        (ctx->Scissor.X != 0 ||
 416         ctx->Scissor.Y != 0 ||
 417         ctx->Scissor.Width < rb->Width ||
 418         ctx->Scissor.Height < rb->Height))
 419       return GL_TRUE;
 420
 421    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.stencilBits > 0)
 422       return GL_TRUE;
 423
 424    return GL_FALSE;
 425 }
 426
 427
 428 /**
 429  * Determine if we need to clear the stencil buffer by drawing a quad.
 430  */
 431 static INLINE GLboolean
 432 check_clear_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 433                               boolean ds_separate)
 434 {
 435    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 436    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 437    const GLuint stencilMax = 0xff;
 438    const GLboolean maskStencil
 439       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 440
 441    assert(rb->Format == MESA_FORMAT_S8 ||
 442           rb->Format == MESA_FORMAT_Z24_S8 ||
 443           rb->Format == MESA_FORMAT_S8_Z24 ||
 444           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 445
 446    if (maskStencil)
 447       return GL_TRUE;
 448
 449    if (ctx->Scissor.Enabled &&
 450        (ctx->Scissor.X != 0 ||
 451         ctx->Scissor.Y != 0 ||
 452         ctx->Scissor.Width < rb->Width ||
 453         ctx->Scissor.Height < rb->Height))
 454       return GL_TRUE;
 455
 456    /* This is correct, but it is necessary to look at the depth clear
 457     * value held in the surface when it comes time to issue the clear,
 458     * rather than taking depth and stencil clear values from the
 459     * current state.
 460     */
 461    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.depthBits > 0)
 462       return GL_TRUE;
 463
 464    return GL_FALSE;
 465 }
 466
 467
 468
 469 /**
 470  * Called when we need to flush.
 471  */
 472 void
 473 st_flush_clear(struct st_context *st)
 474 {
 475    /* Release vertex buffer to avoid synchronous rendering if we were
 476     * to map it in the next frame.
 477     */
 478    pipe_resource_reference(&st->clear.vbuf, NULL);
 479    st->clear.vbuf_slot = 0;
 480 }
 481
 482
 483
 484 /**
 485  * Called via ctx->Driver.Clear()
 486  */
 487 static void
 488 st_Clear(struct gl_context *ctx, GLbitfield mask)
 489 {
 490    static const GLbitfield BUFFER_BITS_DS
 491       = (BUFFER_BIT_DEPTH | BUFFER_BIT_STENCIL);
 492    struct st_context *st = st_context(ctx);
 493    struct gl_renderbuffer *depthRb
 494       = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 495    struct gl_renderbuffer *stencilRb
 496       = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 497    GLbitfield quad_buffers = 0x0;
 498    GLbitfield clear_buffers = 0x0;
 499    GLuint i;
 500
 501    /* This makes sure the pipe has the latest scissor, etc values */
 502    st_validate_state( st );
 503
 504    if (mask & BUFFER_BITS_COLOR) {
 505       for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
 506          GLuint b = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
 507
 508          if (mask & (1 << b)) {
 509             struct gl_renderbuffer *rb
 510                = ctx->DrawBuffer->Attachment[b].Renderbuffer;
 511             struct st_renderbuffer *strb = st_renderbuffer(rb);
 512
 513             if (!strb || !strb->surface)
 514                continue;
 515
 516             if (check_clear_color_with_quad( ctx, rb ))
 517                quad_buffers |= PIPE_CLEAR_COLOR;
 518             else
 519                clear_buffers |= PIPE_CLEAR_COLOR;
 520          }
 521       }
 522    }
 523
 524    if ((mask & BUFFER_BITS_DS) == BUFFER_BITS_DS && depthRb == stencilRb) {
 525       /* clearing combined depth + stencil */
 526       struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 527
 528       if (strb->surface) {
 529          if (check_clear_depth_stencil_with_quad(ctx, depthRb))
 530             quad_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 531          else
 532             clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 533       }
 534    }
 535    else {
 536       /* separate depth/stencil clears */
 537       /* I don't think truly separate buffers are actually possible in gallium or hw? */
 538       if (mask & BUFFER_BIT_DEPTH) {
 539          struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 540
 541          if (strb->surface) {
 542             if (check_clear_depth_with_quad(ctx, depthRb,
 543                                             st->clear.enable_ds_separate))
 544                quad_buffers |= PIPE_CLEAR_DEPTH;
 545             else
 546                clear_buffers |= PIPE_CLEAR_DEPTH;
 547          }
 548       }
 549       if (mask & BUFFER_BIT_STENCIL) {
 550          struct st_renderbuffer *strb = st_renderbuffer(stencilRb);
 551
 552          if (strb->surface) {
 553             if (check_clear_stencil_with_quad(ctx, stencilRb,
 554                                               st->clear.enable_ds_separate))
 555                quad_buffers |= PIPE_CLEAR_STENCIL;
 556             else
 557                clear_buffers |= PIPE_CLEAR_STENCIL;
 558          }
 559       }
 560    }
 561
 562    /*
 563     * If we're going to use clear_with_quad() for any reason, use it for
 564     * everything possible.
 565     */
 566    if (quad_buffers) {
 567       quad_buffers |= clear_buffers;
 568       clear_with_quad(ctx,
 569                       quad_buffers & PIPE_CLEAR_COLOR,
 570                       quad_buffers & PIPE_CLEAR_DEPTH,
 571                       quad_buffers & PIPE_CLEAR_STENCIL);
 572    } else if (clear_buffers) {
 573       /* driver cannot know it can clear everything if the buffer
 574        * is a combined depth/stencil buffer but this wasn't actually
 575        * required from the visual. Hence fix this up to avoid potential
 576        * read-modify-write in the driver.
 577        */
 578       union pipe_color_union clearColor;
 579
 580       if ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) &&
 581           ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) != PIPE_CLEAR_DEPTHSTENCIL) &&
 582           (depthRb == stencilRb) &&
 583           (ctx->DrawBuffer->Visual.depthBits == 0 ||
 584            ctx->DrawBuffer->Visual.stencilBits == 0))
 585          clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 586
 587       if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 588          st_translate_color(ctx->Color.ClearColor.f,
 589                             ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 590                             clearColor.f);
 591       }
 592
 593       st->pipe->clear(st->pipe, clear_buffers, &clearColor,
 594                       ctx->Depth.Clear, ctx->Stencil.Clear);
 595    }
 596    if (mask & BUFFER_BIT_ACCUM)
 597       st_clear_accum_buffer(ctx,
 598                             ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer);
 599 }
 600
 601
 602 void
 603 st_init_clear_functions(struct dd_function_table *functions)
 604 {
 605    functions->Clear = st_Clear;
 606 }