reactos/dll/opengl/mesa/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.raster.depth_clip = 1;
  72    st->clear.enable_ds_separate = pscreen->get_param(pscreen, PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE);
  73 }
  74
  75
  76 /**
  77  * Free per-context state for glClear.
  78  */
  79 void
  80 st_destroy_clear(struct st_context *st)
  81 {
  82    if (st->clear.fs) {
  83       cso_delete_fragment_shader(st->cso_context, st->clear.fs);
  84       st->clear.fs = NULL;
  85    }
  86    if (st->clear.vs) {
  87       cso_delete_vertex_shader(st->cso_context, st->clear.vs);
  88       st->clear.vs = NULL;
  89    }
  90    if (st->clear.vbuf) {
  91       pipe_resource_reference(&st->clear.vbuf, NULL);
  92       st->clear.vbuf = NULL;
  93    }
  94 }
  95
  96
  97 /**
  98  * Helper function to set the fragment shaders.
  99  */
 100 static INLINE void
 101 set_fragment_shader(struct st_context *st)
 102 {
 103    if (!st->clear.fs)
 104       st->clear.fs = util_make_fragment_passthrough_shader(st->pipe);
 105
 106    cso_set_fragment_shader_handle(st->cso_context, st->clear.fs);
 107 }
 108
 109
 110 /**
 111  * Helper function to set the vertex shader.
 112  */
 113 static INLINE void
 114 set_vertex_shader(struct st_context *st)
 115 {
 116    /* vertex shader - still required to provide the linkage between
 117     * fragment shader input semantics and vertex_element/buffers.
 118     */
 119    if (!st->clear.vs)
 120    {
 121       const uint semantic_names[] = { TGSI_SEMANTIC_POSITION,
 122                                       TGSI_SEMANTIC_COLOR };
 123       const uint semantic_indexes[] = { 0, 0 };
 124       st->clear.vs = util_make_vertex_passthrough_shader(st->pipe, 2,
 125                                                          semantic_names,
 126                                                          semantic_indexes);
 127    }
 128
 129    cso_set_vertex_shader_handle(st->cso_context, st->clear.vs);
 130 }
 131
 132
 133 /**
 134  * Draw a screen-aligned quadrilateral.
 135  * Coords are clip coords with y=0=bottom.
 136  */
 137 static void
 138 draw_quad(struct st_context *st,
 139           float x0, float y0, float x1, float y1, GLfloat z,
 140           const union pipe_color_union *color)
 141 {
 142    struct pipe_context *pipe = st->pipe;
 143
 144    /* XXX: Need to improve buffer_write to allow NO_WAIT (as well as
 145     * no_flush) updates to buffers where we know there is no conflict
 146     * with previous data.  Currently using max_slots > 1 will cause
 147     * synchronous rendering if the driver flushes its command buffers
 148     * between one bitmap and the next.  Our flush hook below isn't
 149     * sufficient to catch this as the driver doesn't tell us when it
 150     * flushes its own command buffers.  Until this gets fixed, pay the
 151     * price of allocating a new buffer for each bitmap cache-flush to
 152     * avoid synchronous rendering.
 153     */
 154    const GLuint max_slots = 1; /* 1024 / sizeof(st->clear.vertices); */
 155    GLuint i;
 156
 157    if (st->clear.vbuf_slot >= max_slots) {
 158       pipe_resource_reference(&st->clear.vbuf, NULL);
 159       st->clear.vbuf_slot = 0;
 160    }
 161
 162    if (!st->clear.vbuf) {
 163       st->clear.vbuf = pipe_buffer_create(pipe->screen,
 164                                           PIPE_BIND_VERTEX_BUFFER,
 165                                           PIPE_USAGE_STREAM,
 166                                           max_slots * sizeof(st->clear.vertices));
 167    }
 168
 169    if (!st->clear.vbuf) {
 170       /* ran out of memory */
 171       return;
 172    }
 173
 174    /* positions */
 175    st->clear.vertices[0][0][0] = x0;
 176    st->clear.vertices[0][0][1] = y0;
 177
 178    st->clear.vertices[1][0][0] = x1;
 179    st->clear.vertices[1][0][1] = y0;
 180
 181    st->clear.vertices[2][0][0] = x1;
 182    st->clear.vertices[2][0][1] = y1;
 183
 184    st->clear.vertices[3][0][0] = x0;
 185    st->clear.vertices[3][0][1] = y1;
 186
 187    /* same for all verts: */
 188    for (i = 0; i < 4; i++) {
 189       st->clear.vertices[i][0][2] = z;
 190       st->clear.vertices[i][0][3] = 1.0;
 191       st->clear.vertices[i][1][0] = color->f[0];
 192       st->clear.vertices[i][1][1] = color->f[1];
 193       st->clear.vertices[i][1][2] = color->f[2];
 194       st->clear.vertices[i][1][3] = color->f[3];
 195    }
 196
 197    /* put vertex data into vbuf */
 198    pipe_buffer_write_nooverlap(st->pipe, st->clear.vbuf,
 199                                            st->clear.vbuf_slot
 200                                              * sizeof(st->clear.vertices),
 201                                            sizeof(st->clear.vertices),
 202                                            st->clear.vertices);
 203
 204    /* draw */
 205    util_draw_vertex_buffer(pipe,
 206                            st->cso_context,
 207                            st->clear.vbuf,
 208                            st->clear.vbuf_slot * sizeof(st->clear.vertices),
 209                            PIPE_PRIM_TRIANGLE_FAN,
 210                            4,  /* verts */
 211                            2); /* attribs/vert */
 212
 213    /* Increment slot */
 214    st->clear.vbuf_slot++;
 215 }
 216
 217
 218
 219 /**
 220  * Do glClear by drawing a quadrilateral.
 221  * The vertices of the quad will be computed from the
 222  * ctx->DrawBuffer->_X/Ymin/max fields.
 223  */
 224 static void
 225 clear_with_quad(struct gl_context *ctx,
 226                 GLboolean color, GLboolean depth, GLboolean stencil)
 227 {
 228    struct st_context *st = st_context(ctx);
 229    const struct gl_framebuffer *fb = ctx->DrawBuffer;
 230    const GLfloat fb_width = (GLfloat) fb->Width;
 231    const GLfloat fb_height = (GLfloat) fb->Height;
 232    const GLfloat x0 = (GLfloat) ctx->DrawBuffer->_Xmin / fb_width * 2.0f - 1.0f;
 233    const GLfloat x1 = (GLfloat) ctx->DrawBuffer->_Xmax / fb_width * 2.0f - 1.0f;
 234    const GLfloat y0 = (GLfloat) ctx->DrawBuffer->_Ymin / fb_height * 2.0f - 1.0f;
 235    const GLfloat y1 = (GLfloat) ctx->DrawBuffer->_Ymax / fb_height * 2.0f - 1.0f;
 236    union pipe_color_union clearColor;
 237
 238    /*
 239    printf("%s %s%s%s %f,%f %f,%f\n", __FUNCTION__,
 240           color ? "color, " : "",
 241           depth ? "depth, " : "",
 242           stencil ? "stencil" : "",
 243           x0, y0,
 244           x1, y1);
 245    */
 246
 247    cso_save_blend(st->cso_context);
 248    cso_save_stencil_ref(st->cso_context);
 249    cso_save_depth_stencil_alpha(st->cso_context);
 250    cso_save_rasterizer(st->cso_context);
 251    cso_save_viewport(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    set_fragment_shader(st);
 330    set_vertex_shader(st);
 331    cso_set_geometry_shader_handle(st->cso_context, NULL);
 332
 333    if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 334       st_translate_color(ctx->Color.ClearColor.f,
 335                                ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 336                                clearColor.f);
 337    }
 338
 339    /* draw quad matching scissor rect */
 340    draw_quad(st, x0, y0, x1, y1, (GLfloat) ctx->Depth.Clear, &clearColor);
 341
 342    /* Restore pipe state */
 343    cso_restore_blend(st->cso_context);
 344    cso_restore_stencil_ref(st->cso_context);
 345    cso_restore_depth_stencil_alpha(st->cso_context);
 346    cso_restore_rasterizer(st->cso_context);
 347    cso_restore_viewport(st->cso_context);
 348    cso_restore_fragment_shader(st->cso_context);
 349    cso_restore_vertex_shader(st->cso_context);
 350    cso_restore_geometry_shader(st->cso_context);
 351    cso_restore_vertex_elements(st->cso_context);
 352    cso_restore_vertex_buffers(st->cso_context);
 353    cso_restore_stream_outputs(st->cso_context);
 354 }
 355
 356
 357 /**
 358  * Determine if we need to clear the depth buffer by drawing a quad.
 359  */
 360 static INLINE GLboolean
 361 check_clear_color_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 362 {
 363    if (ctx->Scissor.Enabled &&
 364        (ctx->Scissor.X != 0 ||
 365         ctx->Scissor.Y != 0 ||
 366         ctx->Scissor.Width < rb->Width ||
 367         ctx->Scissor.Height < rb->Height))
 368       return GL_TRUE;
 369
 370    if (!ctx->Color.ColorMask[0][0] ||
 371        !ctx->Color.ColorMask[0][1] ||
 372        !ctx->Color.ColorMask[0][2] ||
 373        !ctx->Color.ColorMask[0][3])
 374       return GL_TRUE;
 375
 376    return GL_FALSE;
 377 }
 378
 379
 380 /**
 381  * Determine if we need to clear the combiend depth/stencil buffer by
 382  * drawing a quad.
 383  */
 384 static INLINE GLboolean
 385 check_clear_depth_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb)
 386 {
 387    const GLuint stencilMax = 0xff;
 388    GLboolean maskStencil
 389       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 390
 391    assert(rb->Format == MESA_FORMAT_S8 ||
 392           rb->Format == MESA_FORMAT_Z24_S8 ||
 393           rb->Format == MESA_FORMAT_S8_Z24 ||
 394           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 395
 396    if (ctx->Scissor.Enabled &&
 397        (ctx->Scissor.X != 0 ||
 398         ctx->Scissor.Y != 0 ||
 399         ctx->Scissor.Width < rb->Width ||
 400         ctx->Scissor.Height < rb->Height))
 401       return GL_TRUE;
 402
 403    if (maskStencil)
 404       return GL_TRUE;
 405
 406    return GL_FALSE;
 407 }
 408
 409
 410 /**
 411  * Determine if we need to clear the depth buffer by drawing a quad.
 412  */
 413 static INLINE GLboolean
 414 check_clear_depth_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 415                             boolean ds_separate)
 416 {
 417    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 418    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 419
 420    if (ctx->Scissor.Enabled &&
 421        (ctx->Scissor.X != 0 ||
 422         ctx->Scissor.Y != 0 ||
 423         ctx->Scissor.Width < rb->Width ||
 424         ctx->Scissor.Height < rb->Height))
 425       return GL_TRUE;
 426
 427    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.stencilBits > 0)
 428       return GL_TRUE;
 429
 430    return GL_FALSE;
 431 }
 432
 433
 434 /**
 435  * Determine if we need to clear the stencil buffer by drawing a quad.
 436  */
 437 static INLINE GLboolean
 438 check_clear_stencil_with_quad(struct gl_context *ctx, struct gl_renderbuffer *rb,
 439                               boolean ds_separate)
 440 {
 441    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 442    const GLboolean isDS = util_format_is_depth_and_stencil(strb->surface->format);
 443    const GLuint stencilMax = 0xff;
 444    const GLboolean maskStencil
 445       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 446
 447    assert(rb->Format == MESA_FORMAT_S8 ||
 448           rb->Format == MESA_FORMAT_Z24_S8 ||
 449           rb->Format == MESA_FORMAT_S8_Z24 ||
 450           rb->Format == MESA_FORMAT_Z32_FLOAT_X24S8);
 451
 452    if (maskStencil)
 453       return GL_TRUE;
 454
 455    if (ctx->Scissor.Enabled &&
 456        (ctx->Scissor.X != 0 ||
 457         ctx->Scissor.Y != 0 ||
 458         ctx->Scissor.Width < rb->Width ||
 459         ctx->Scissor.Height < rb->Height))
 460       return GL_TRUE;
 461
 462    /* This is correct, but it is necessary to look at the depth clear
 463     * value held in the surface when it comes time to issue the clear,
 464     * rather than taking depth and stencil clear values from the
 465     * current state.
 466     */
 467    if (!ds_separate && isDS && ctx->DrawBuffer->Visual.depthBits > 0)
 468       return GL_TRUE;
 469
 470    return GL_FALSE;
 471 }
 472
 473
 474
 475 /**
 476  * Called when we need to flush.
 477  */
 478 void
 479 st_flush_clear(struct st_context *st)
 480 {
 481    /* Release vertex buffer to avoid synchronous rendering if we were
 482     * to map it in the next frame.
 483     */
 484    pipe_resource_reference(&st->clear.vbuf, NULL);
 485    st->clear.vbuf_slot = 0;
 486 }
 487
 488
 489
 490 /**
 491  * Called via ctx->Driver.Clear()
 492  */
 493 static void
 494 st_Clear(struct gl_context *ctx, GLbitfield mask)
 495 {
 496    static const GLbitfield BUFFER_BITS_DS
 497       = (BUFFER_BIT_DEPTH | BUFFER_BIT_STENCIL);
 498    struct st_context *st = st_context(ctx);
 499    struct gl_renderbuffer *depthRb
 500       = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 501    struct gl_renderbuffer *stencilRb
 502       = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 503    GLbitfield quad_buffers = 0x0;
 504    GLbitfield clear_buffers = 0x0;
 505    GLuint i;
 506
 507    /* This makes sure the pipe has the latest scissor, etc values */
 508    st_validate_state( st );
 509
 510    if (mask & BUFFER_BITS_COLOR) {
 511       for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
 512          GLuint b = ctx->DrawBuffer->_ColorDrawBufferIndexes[i];
 513
 514          if (mask & (1 << b)) {
 515             struct gl_renderbuffer *rb
 516                = ctx->DrawBuffer->Attachment[b].Renderbuffer;
 517             struct st_renderbuffer *strb = st_renderbuffer(rb);
 518
 519             if (!strb || !strb->surface)
 520                continue;
 521
 522             if (check_clear_color_with_quad( ctx, rb ))
 523                quad_buffers |= PIPE_CLEAR_COLOR;
 524             else
 525                clear_buffers |= PIPE_CLEAR_COLOR;
 526          }
 527       }
 528    }
 529
 530    if ((mask & BUFFER_BITS_DS) == BUFFER_BITS_DS && depthRb == stencilRb) {
 531       /* clearing combined depth + stencil */
 532       struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 533
 534       if (strb->surface) {
 535          if (check_clear_depth_stencil_with_quad(ctx, depthRb))
 536             quad_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 537          else
 538             clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 539       }
 540    }
 541    else {
 542       /* separate depth/stencil clears */
 543       /* I don't think truly separate buffers are actually possible in gallium or hw? */
 544       if (mask & BUFFER_BIT_DEPTH) {
 545          struct st_renderbuffer *strb = st_renderbuffer(depthRb);
 546
 547          if (strb->surface) {
 548             if (check_clear_depth_with_quad(ctx, depthRb,
 549                                             st->clear.enable_ds_separate))
 550                quad_buffers |= PIPE_CLEAR_DEPTH;
 551             else
 552                clear_buffers |= PIPE_CLEAR_DEPTH;
 553          }
 554       }
 555       if (mask & BUFFER_BIT_STENCIL) {
 556          struct st_renderbuffer *strb = st_renderbuffer(stencilRb);
 557
 558          if (strb->surface) {
 559             if (check_clear_stencil_with_quad(ctx, stencilRb,
 560                                               st->clear.enable_ds_separate))
 561                quad_buffers |= PIPE_CLEAR_STENCIL;
 562             else
 563                clear_buffers |= PIPE_CLEAR_STENCIL;
 564          }
 565       }
 566    }
 567
 568    /*
 569     * If we're going to use clear_with_quad() for any reason, use it for
 570     * everything possible.
 571     */
 572    if (quad_buffers) {
 573       quad_buffers |= clear_buffers;
 574       clear_with_quad(ctx,
 575                       quad_buffers & PIPE_CLEAR_COLOR,
 576                       quad_buffers & PIPE_CLEAR_DEPTH,
 577                       quad_buffers & PIPE_CLEAR_STENCIL);
 578    } else if (clear_buffers) {
 579       /* driver cannot know it can clear everything if the buffer
 580        * is a combined depth/stencil buffer but this wasn't actually
 581        * required from the visual. Hence fix this up to avoid potential
 582        * read-modify-write in the driver.
 583        */
 584       union pipe_color_union clearColor;
 585
 586       if ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) &&
 587           ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) != PIPE_CLEAR_DEPTHSTENCIL) &&
 588           (depthRb == stencilRb) &&
 589           (ctx->DrawBuffer->Visual.depthBits == 0 ||
 590            ctx->DrawBuffer->Visual.stencilBits == 0))
 591          clear_buffers |= PIPE_CLEAR_DEPTHSTENCIL;
 592
 593       if (ctx->DrawBuffer->_ColorDrawBuffers[0]) {
 594          st_translate_color(ctx->Color.ClearColor.f,
 595                             ctx->DrawBuffer->_ColorDrawBuffers[0]->_BaseFormat,
 596                             clearColor.f);
 597       }
 598
 599       st->pipe->clear(st->pipe, clear_buffers, &clearColor,
 600                       ctx->Depth.Clear, ctx->Stencil.Clear);
 601    }
 602    if (mask & BUFFER_BIT_ACCUM)
 603       _mesa_clear_accum_buffer(ctx);
 604 }
 605
 606
 607 void
 608 st_init_clear_functions(struct dd_function_table *functions)
 609 {
 610    functions->Clear = st_Clear;
 611 }