src/mesa/state_tracker/st_cb_clear.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   * Authors:
  30   *   Keith Whitwell <keith@tungstengraphics.com>
  31   *   Brian Paul
  32   */
  33
  34 #include "main/glheader.h"
  35 #include "main/macros.h"
  36 #include "shader/prog_instruction.h"
  37 #include "st_atom.h"
  38 #include "st_cache.h"
  39 #include "st_context.h"
  40 #include "st_cb_accum.h"
  41 #include "st_cb_clear.h"
  42 #include "st_cb_fbo.h"
  43 #include "st_draw.h"
  44 #include "st_program.h"
  45 #include "st_public.h"
  46 #include "st_mesa_to_tgsi.h"
  47
  48 #include "pipe/p_context.h"
  49 #include "pipe/p_state.h"
  50 #include "pipe/p_defines.h"
  51 #include "pipe/p_winsys.h"
  52
  53
  54
  55
  56
  57 static GLuint
  58 color_value(GLuint pipeFormat, const GLfloat color[4])
  59 {
  60    GLubyte r, g, b, a;
  61
  62    UNCLAMPED_FLOAT_TO_UBYTE(r, color[0]);
  63    UNCLAMPED_FLOAT_TO_UBYTE(g, color[1]);
  64    UNCLAMPED_FLOAT_TO_UBYTE(b, color[2]);
  65    UNCLAMPED_FLOAT_TO_UBYTE(a, color[3]);
  66
  67    switch (pipeFormat) {
  68    case PIPE_FORMAT_R8G8B8A8_UNORM:
  69       return (r << 24) | (g << 16) | (b << 8) | a;
  70    case PIPE_FORMAT_A8R8G8B8_UNORM:
  71       return (a << 24) | (r << 16) | (g << 8) | b;
  72    case PIPE_FORMAT_B8G8R8A8_UNORM:
  73       return (b << 24) | (g << 16) | (r << 8) | a;
  74    case PIPE_FORMAT_R5G6B5_UNORM:
  75       return ((r & 0xf8) << 8) | ((g & 0xfc) << 3) | (b >> 3);
  76    default:
  77       assert(0);
  78       return 0;
  79    }
  80 }
  81
  82
  83 static uint
  84 depth_value(GLuint pipeFormat, GLfloat value)
  85 {
  86    switch (pipeFormat) {
  87    case PIPE_FORMAT_Z16_UNORM:
  88       return (uint) (value * 0xffff);
  89    case PIPE_FORMAT_Z32_UNORM:
  90       /* special-case to avoid overflow */
  91       if (value == 1.0)
  92          return 0xffffffff;
  93       else
  94          return (uint) (value * 0xffffffff);
  95    case PIPE_FORMAT_S8Z24_UNORM:
  96       return (uint) (value * 0xffffff);
  97    case PIPE_FORMAT_Z24S8_UNORM:
  98       return ((uint) (value * 0xffffff)) << 8;
  99    default:
 100       assert(0);
 101       return 0;
 102    }
 103 }
 104
 105
 106 static GLboolean
 107 is_depth_stencil_format(GLuint pipeFormat)
 108 {
 109    switch (pipeFormat) {
 110    case PIPE_FORMAT_S8Z24_UNORM:
 111    case PIPE_FORMAT_Z24S8_UNORM:
 112       return GL_TRUE;
 113    default:
 114       return GL_FALSE;
 115    }
 116 }
 117
 118
 119
 120 /**
 121  * Create a simple fragment shader that just passes through the fragment color.
 122  */
 123 static struct st_fragment_program *
 124 make_frag_shader(struct st_context *st)
 125 {
 126    GLcontext *ctx = st->ctx;
 127    struct st_fragment_program *stfp;
 128    struct gl_program *p;
 129    GLuint interpMode[16];
 130    GLuint i;
 131
 132    /* XXX temporary */
 133    for (i = 0; i < 16; i++)
 134       interpMode[i] = TGSI_INTERPOLATE_LINEAR;
 135
 136    p = ctx->Driver.NewProgram(ctx, GL_FRAGMENT_PROGRAM_ARB, 0);
 137    if (!p)
 138       return NULL;
 139
 140    p->NumInstructions = 2;
 141    p->Instructions = _mesa_alloc_instructions(2);
 142    if (!p->Instructions) {
 143       ctx->Driver.DeleteProgram(ctx, p);
 144       return NULL;
 145    }
 146    _mesa_init_instructions(p->Instructions, 2);
 147    /* MOV result.color, fragment.color; */
 148    p->Instructions[0].Opcode = OPCODE_MOV;
 149    p->Instructions[0].DstReg.File = PROGRAM_OUTPUT;
 150    p->Instructions[0].DstReg.Index = FRAG_RESULT_COLR;
 151    p->Instructions[0].SrcReg[0].File = PROGRAM_INPUT;
 152    p->Instructions[0].SrcReg[0].Index = FRAG_ATTRIB_COL0;
 153    /* END; */
 154    p->Instructions[1].Opcode = OPCODE_END;
 155
 156    p->InputsRead = FRAG_BIT_COL0;
 157    p->OutputsWritten = (1 << FRAG_RESULT_COLR);
 158
 159    stfp = (struct st_fragment_program *) p;
 160    st_translate_fragment_program(st, stfp, NULL,
 161                                  stfp->tokens, ST_MAX_SHADER_TOKENS);
 162
 163    return stfp;
 164 }
 165
 166
 167 /**
 168  * Create a simple vertex shader that just passes through the
 169  * vertex position and color.
 170  */
 171 static struct st_vertex_program *
 172 make_vertex_shader(struct st_context *st)
 173 {
 174    GLcontext *ctx = st->ctx;
 175    struct st_vertex_program *stvp;
 176    struct gl_program *p;
 177
 178    p = ctx->Driver.NewProgram(ctx, GL_VERTEX_PROGRAM_ARB, 0);
 179    if (!p)
 180       return NULL;
 181
 182    p->NumInstructions = 3;
 183    p->Instructions = _mesa_alloc_instructions(3);
 184    if (!p->Instructions) {
 185       ctx->Driver.DeleteProgram(ctx, p);
 186       return NULL;
 187    }
 188    _mesa_init_instructions(p->Instructions, 3);
 189    /* MOV result.pos, vertex.pos; */
 190    p->Instructions[0].Opcode = OPCODE_MOV;
 191    p->Instructions[0].DstReg.File = PROGRAM_OUTPUT;
 192    p->Instructions[0].DstReg.Index = VERT_RESULT_HPOS;
 193    p->Instructions[0].SrcReg[0].File = PROGRAM_INPUT;
 194    p->Instructions[0].SrcReg[0].Index = VERT_ATTRIB_POS;
 195    /* MOV result.color, vertex.color; */
 196    p->Instructions[1].Opcode = OPCODE_MOV;
 197    p->Instructions[1].DstReg.File = PROGRAM_OUTPUT;
 198    p->Instructions[1].DstReg.Index = VERT_RESULT_COL0;
 199    p->Instructions[1].SrcReg[0].File = PROGRAM_INPUT;
 200    p->Instructions[1].SrcReg[0].Index = VERT_ATTRIB_COLOR0;
 201    /* END; */
 202    p->Instructions[2].Opcode = OPCODE_END;
 203
 204    p->InputsRead = VERT_BIT_POS | VERT_BIT_COLOR0;
 205    p->OutputsWritten = ((1 << VERT_RESULT_COL0) |
 206                         (1 << VERT_RESULT_HPOS));
 207
 208    stvp = (struct st_vertex_program *) p;
 209    st_translate_vertex_program(st, stvp, NULL,
 210                                stvp->tokens, ST_MAX_SHADER_TOKENS);
 211    assert(stvp->vs);
 212
 213    return stvp;
 214 }
 215
 216
 217
 218 /**
 219  * Draw a screen-aligned quadrilateral.
 220  * Coords are window coords with y=0=bottom.  These coords will be transformed
 221  * by the vertex shader and viewport transform (which will flip Y if needed).
 222  */
 223 static void
 224 draw_quad(GLcontext *ctx,
 225           float x0, float y0, float x1, float y1, GLfloat z,
 226           const GLfloat color[4])
 227 {
 228    GLfloat verts[4][2][4]; /* four verts, two attribs, XYZW */
 229    GLuint i;
 230
 231    /* positions */
 232    verts[0][0][0] = x0;
 233    verts[0][0][1] = y0;
 234
 235    verts[1][0][0] = x1;
 236    verts[1][0][1] = y0;
 237
 238    verts[2][0][0] = x1;
 239    verts[2][0][1] = y1;
 240
 241    verts[3][0][0] = x0;
 242    verts[3][0][1] = y1;
 243
 244    /* same for all verts: */
 245    for (i = 0; i < 4; i++) {
 246       verts[i][0][2] = z;
 247       verts[i][0][3] = 1.0;
 248       verts[i][1][0] = color[0];
 249       verts[i][1][1] = color[1];
 250       verts[i][1][2] = color[2];
 251       verts[i][1][3] = color[3];
 252    }
 253
 254    st_draw_vertices(ctx, PIPE_PRIM_QUADS, 4, (float *) verts, 2);
 255 }
 256
 257
 258
 259 /**
 260  * Do glClear by drawing a quadrilateral.
 261  * The vertices of the quad will be computed from the
 262  * ctx->DrawBuffer->_X/Ymin/max fields.
 263  */
 264 static void
 265 clear_with_quad(GLcontext *ctx,
 266                 GLboolean color, GLboolean depth, GLboolean stencil)
 267 {
 268    struct st_context *st = ctx->st;
 269    struct pipe_context *pipe = st->pipe;
 270    const GLfloat x0 = ctx->DrawBuffer->_Xmin;
 271    const GLfloat y0 = ctx->DrawBuffer->_Ymin;
 272    const GLfloat x1 = ctx->DrawBuffer->_Xmax;
 273    const GLfloat y1 = ctx->DrawBuffer->_Ymax;
 274
 275    /* alpha state: disabled */
 276    {
 277       struct pipe_alpha_test_state alpha_test;
 278       const struct cso_alpha_test *cso;
 279       memset(&alpha_test, 0, sizeof(alpha_test));
 280       cso = st_cached_alpha_test_state(st, &alpha_test);
 281       pipe->bind_alpha_test_state(pipe, cso->data);
 282    }
 283
 284    /* blend state: RGBA masking */
 285    {
 286       struct pipe_blend_state blend;
 287       const struct cso_blend *cso;
 288       memset(&blend, 0, sizeof(blend));
 289       if (color) {
 290          if (ctx->Color.ColorMask[0])
 291             blend.colormask |= PIPE_MASK_R;
 292          if (ctx->Color.ColorMask[1])
 293             blend.colormask |= PIPE_MASK_G;
 294          if (ctx->Color.ColorMask[2])
 295             blend.colormask |= PIPE_MASK_B;
 296          if (ctx->Color.ColorMask[3])
 297             blend.colormask |= PIPE_MASK_A;
 298          if (st->ctx->Color.DitherFlag)
 299             blend.dither = 1;
 300       }
 301       cso = st_cached_blend_state(st, &blend);
 302       pipe->bind_blend_state(pipe, cso->data);
 303    }
 304
 305    /* depth_stencil state: always pass/set to ref value */
 306    {
 307       struct pipe_depth_stencil_state depth_stencil;
 308       const struct cso_depth_stencil *cso;
 309       memset(&depth_stencil, 0, sizeof(depth_stencil));
 310       if (depth) {
 311          depth_stencil.depth.enabled = 1;
 312          depth_stencil.depth.writemask = 1;
 313          depth_stencil.depth.func = PIPE_FUNC_ALWAYS;
 314       }
 315
 316       if (stencil) {
 317          depth_stencil.stencil.front_enabled = 1;
 318          depth_stencil.stencil.front_func = PIPE_FUNC_ALWAYS;
 319          depth_stencil.stencil.front_fail_op = PIPE_STENCIL_OP_REPLACE;
 320          depth_stencil.stencil.front_zpass_op = PIPE_STENCIL_OP_REPLACE;
 321          depth_stencil.stencil.front_zfail_op = PIPE_STENCIL_OP_REPLACE;
 322          depth_stencil.stencil.ref_value[0] = ctx->Stencil.Clear;
 323          depth_stencil.stencil.value_mask[0] = 0xff;
 324          depth_stencil.stencil.write_mask[0] = ctx->Stencil.WriteMask[0] & 0xff;
 325       }
 326       cso = st_cached_depth_stencil_state(st, &depth_stencil);
 327       pipe->bind_depth_stencil_state(pipe, cso->data);
 328    }
 329
 330    /* rasterizer state: nothing */
 331    {
 332       struct pipe_rasterizer_state raster;
 333       const struct cso_rasterizer *cso;
 334       memset(&raster, 0, sizeof(raster));
 335 #if 0
 336       /* don't do per-pixel scissor; we'll just draw a PIPE_PRIM_QUAD
 337        * that matches the scissor bounds.
 338        */
 339       if (ctx->Scissor.Enabled)
 340          raster.scissor = 1;
 341 #endif
 342       cso = st_cached_rasterizer_state(st, &raster);
 343       pipe->bind_rasterizer_state(pipe, cso->data);
 344    }
 345
 346    /* fragment shader state: color pass-through program */
 347    {
 348       static struct st_fragment_program *stfp = NULL;
 349       if (!stfp) {
 350          stfp = make_frag_shader(st);
 351       }
 352       pipe->bind_fs_state(pipe, stfp->fs->data);
 353    }
 354
 355    /* vertex shader state: color/position pass-through */
 356    {
 357       static struct st_vertex_program *stvp = NULL;
 358       if (!stvp) {
 359          stvp = make_vertex_shader(st);
 360       }
 361       pipe->bind_vs_state(pipe, stvp->vs->data);
 362    }
 363
 364    /* viewport state: viewport matching window dims */
 365    {
 366       const float width = ctx->DrawBuffer->Width;
 367       const float height = ctx->DrawBuffer->Height;
 368       struct pipe_viewport_state vp;
 369       vp.scale[0] =  0.5 * width;
 370       vp.scale[1] = -0.5 * height;
 371       vp.scale[2] = 1.0;
 372       vp.scale[3] = 1.0;
 373       vp.translate[0] = 0.5 * width;
 374       vp.translate[1] = 0.5 * height;
 375       vp.translate[2] = 0.0;
 376       vp.translate[3] = 0.0;
 377       pipe->set_viewport_state(pipe, &vp);
 378    }
 379
 380    /* draw quad matching scissor rect (XXX verify coord round-off) */
 381    draw_quad(ctx, x0, y0, x1, y1, ctx->Depth.Clear, ctx->Color.ClearColor);
 382
 383    /* Restore pipe state */
 384    pipe->bind_alpha_test_state(pipe, st->state.alpha_test->data);
 385    pipe->bind_blend_state(pipe, st->state.blend->data);
 386    pipe->bind_depth_stencil_state(pipe, st->state.depth_stencil->data);
 387    pipe->bind_fs_state(pipe, st->state.fs->data);
 388    pipe->bind_vs_state(pipe, st->state.vs->data);
 389    pipe->bind_rasterizer_state(pipe, st->state.rasterizer->data);
 390    pipe->set_viewport_state(pipe, &st->state.viewport);
 391    /* OR:
 392    st_invalidate_state(ctx, _NEW_COLOR | _NEW_DEPTH | _NEW_STENCIL);
 393    */
 394 }
 395
 396
 397 /**
 398  * Determine if we need to clear the depth buffer by drawing a quad.
 399  */
 400 static INLINE GLboolean
 401 check_clear_color_with_quad(GLcontext *ctx)
 402 {
 403    return !(ctx->Color.ColorMask[0] &&
 404             ctx->Color.ColorMask[1] &&
 405             ctx->Color.ColorMask[2] &&
 406             ctx->Color.ColorMask[3] &&
 407             !ctx->Scissor.Enabled);
 408 }
 409
 410
 411 /**
 412  * Determine if we need to clear the depth buffer by drawing a quad.
 413  */
 414 static INLINE GLboolean
 415 check_clear_depth_with_quad(GLcontext *ctx, struct gl_renderbuffer *rb)
 416 {
 417    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 418    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 419    return  ctx->Scissor.Enabled
 420       || (isDS && ctx->DrawBuffer->Visual.stencilBits > 0);
 421 }
 422
 423
 424 /**
 425  * Determine if we need to clear the stencil buffer by drawing a quad.
 426  */
 427 static INLINE GLboolean
 428 check_clear_stencil_with_quad(GLcontext *ctx, struct gl_renderbuffer *rb)
 429 {
 430    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 431    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 432    const GLuint stencilMax = (1 << rb->StencilBits) - 1;
 433    const GLboolean maskStencil
 434       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 435    return maskStencil
 436       || ctx->Scissor.Enabled
 437       || (isDS && ctx->DrawBuffer->Visual.depthBits > 0);
 438 }
 439
 440
 441
 442
 443 static void
 444 clear_color_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 445 {
 446    struct st_renderbuffer *strb = st_renderbuffer(rb);
 447
 448    if (ctx->Color.ColorMask[0] &&
 449        ctx->Color.ColorMask[1] &&
 450        ctx->Color.ColorMask[2] &&
 451        ctx->Color.ColorMask[3] &&
 452        !ctx->Scissor.Enabled)
 453    {
 454       /* clear whole buffer w/out masking */
 455       GLuint clearValue
 456          = color_value(strb->surface->format, ctx->Color.ClearColor);
 457       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 458    }
 459    else {
 460       /* masking or scissoring */
 461       clear_with_quad(ctx, GL_TRUE, GL_FALSE, GL_FALSE);
 462    }
 463 }
 464
 465
 466 static void
 467 clear_depth_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 468 {
 469    struct st_renderbuffer *strb = st_renderbuffer(rb);
 470    /*
 471    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 472    */
 473
 474    assert(strb->surface->format);
 475
 476    if (check_clear_depth_with_quad(ctx, rb)) {
 477       /* scissoring or we have a combined depth/stencil buffer */
 478       clear_with_quad(ctx, GL_FALSE, GL_TRUE, GL_FALSE);
 479    }
 480    else {
 481       /* simple clear of whole buffer */
 482       uint clearValue = depth_value(strb->surface->format, ctx->Depth.Clear);
 483       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 484    }
 485 }
 486
 487
 488 static void
 489 clear_stencil_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 490 {
 491    struct st_renderbuffer *strb = st_renderbuffer(rb);
 492    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 493    const GLuint stencilMax = (1 << rb->StencilBits) - 1;
 494    GLboolean maskStencil
 495       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 496
 497    if (maskStencil ||
 498        ctx->Scissor.Enabled ||
 499        (isDS && ctx->DrawBuffer->Visual.depthBits > 0)) {
 500       /* masking or scissoring or combined depth/stencil buffer */
 501       clear_with_quad(ctx, GL_FALSE, GL_FALSE, GL_TRUE);
 502    }
 503    else {
 504       /* simple clear of whole buffer */
 505       GLuint clearValue = ctx->Stencil.Clear;
 506       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 507    }
 508 }
 509
 510
 511 static void
 512 clear_depth_stencil_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 513 {
 514    struct st_renderbuffer *strb = st_renderbuffer(rb);
 515    const GLuint stencilMax = (1 << rb->StencilBits) - 1;
 516    GLboolean maskStencil
 517       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 518
 519    assert(is_depth_stencil_format(strb->surface->format));
 520
 521    if (!maskStencil && !ctx->Scissor.Enabled) {
 522       /* clear whole buffer w/out masking */
 523       GLuint clearValue = depth_value(strb->surface->format, ctx->Depth.Clear);
 524
 525       switch (strb->surface->format) {
 526       case PIPE_FORMAT_S8Z24_UNORM:
 527          clearValue |= ctx->Stencil.Clear << 24;
 528          break;
 529       case PIPE_FORMAT_Z24S8_UNORM:
 530          clearValue |= clearValue | ctx->Stencil.Clear;
 531          break;
 532       default:
 533          assert(0);
 534       }
 535
 536       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 537    }
 538    else {
 539       /* masking or scissoring */
 540       clear_with_quad(ctx, GL_FALSE, GL_TRUE, GL_TRUE);
 541    }
 542 }
 543
 544
 545
 546 /**
 547  * Called via ctx->Driver.Clear()
 548  * XXX: doesn't pick up the differences between front/back/left/right
 549  * clears.  Need to sort that out...
 550  */
 551 static void st_clear(GLcontext *ctx, GLbitfield mask)
 552 {
 553    static const GLbitfield BUFFER_BITS_DS
 554       = (BUFFER_BIT_DEPTH | BUFFER_BIT_STENCIL);
 555    struct st_context *st = ctx->st;
 556    struct gl_renderbuffer *depthRb
 557       = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 558    struct gl_renderbuffer *stencilRb
 559       = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 560    GLbitfield cmask = mask & BUFFER_BITS_COLOR;
 561
 562    /* This makes sure the softpipe has the latest scissor, etc values */
 563    st_validate_state( st );
 564
 565    /*
 566     * XXX TO-DO:
 567     * If we're going to use clear_with_quad() for any reason, use it to
 568     * clear as many other buffers as possible.
 569     * As it is now, we sometimes call clear_with_quad() three times to clear
 570     * color/depth/stencil individually...
 571     */
 572
 573    if (cmask) {
 574       GLuint b;
 575       for (b = 0; cmask; b++) {
 576          if (cmask & (1 << b)) {
 577             struct gl_renderbuffer *rb
 578                = ctx->DrawBuffer->Attachment[b].Renderbuffer;
 579             assert(rb);
 580             clear_color_buffer(ctx, rb);
 581             cmask &= ~(1 << b); /* turn off bit */
 582          }
 583          assert(b < BUFFER_COUNT);
 584       }
 585    }
 586
 587    if (mask & BUFFER_BIT_ACCUM) {
 588       st_clear_accum_buffer(ctx,
 589                        ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer);
 590    }
 591
 592    if ((mask & BUFFER_BITS_DS) == BUFFER_BITS_DS && depthRb == stencilRb) {
 593       /* clearing combined depth + stencil */
 594       clear_depth_stencil_buffer(ctx, depthRb);
 595    }
 596    else {
 597       /* separate depth/stencil clears */
 598       if (mask & BUFFER_BIT_DEPTH) {
 599          clear_depth_buffer(ctx, depthRb);
 600       }
 601       if (mask & BUFFER_BIT_STENCIL) {
 602          clear_stencil_buffer(ctx, stencilRb);
 603       }
 604    }
 605 }
 606
 607
 608 void st_init_clear_functions(struct dd_function_table *functions)
 609 {
 610    functions->Clear = st_clear;
 611 }