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_context.h"
  39 #include "st_cb_accum.h"
  40 #include "st_cb_clear.h"
  41 #include "st_cb_fbo.h"
  42 #include "st_draw.h"
  43 #include "st_program.h"
  44 #include "st_public.h"
  45 #include "st_mesa_to_tgsi.h"
  46
  47 #include "pipe/p_context.h"
  48 #include "pipe/p_state.h"
  49 #include "pipe/p_defines.h"
  50 #include "pipe/p_winsys.h"
  51 #include "util/u_pack_color.h"
  52
  53 #include "cso_cache/cso_context.h"
  54
  55
  56 /* XXX for testing draw module vertex passthrough: */
  57 #define TEST_DRAW_PASSTHROUGH 0
  58
  59
  60 static GLboolean
  61 is_depth_stencil_format(enum pipe_format pipeFormat)
  62 {
  63    switch (pipeFormat) {
  64    case PIPE_FORMAT_S8Z24_UNORM:
  65    case PIPE_FORMAT_Z24S8_UNORM:
  66       return GL_TRUE;
  67    default:
  68       return GL_FALSE;
  69    }
  70 }
  71
  72
  73
  74 /**
  75  * Create a simple fragment shader that just passes through the fragment color.
  76  */
  77 static struct st_fragment_program *
  78 make_frag_shader(struct st_context *st)
  79 {
  80    GLcontext *ctx = st->ctx;
  81    struct st_fragment_program *stfp;
  82    struct gl_program *p;
  83    GLuint interpMode[16];
  84    GLuint i;
  85
  86    /* XXX temporary */
  87    for (i = 0; i < 16; i++)
  88       interpMode[i] = TGSI_INTERPOLATE_LINEAR;
  89
  90    p = ctx->Driver.NewProgram(ctx, GL_FRAGMENT_PROGRAM_ARB, 0);
  91    if (!p)
  92       return NULL;
  93
  94    p->NumInstructions = 2;
  95    p->Instructions = _mesa_alloc_instructions(2);
  96    if (!p->Instructions) {
  97       ctx->Driver.DeleteProgram(ctx, p);
  98       return NULL;
  99    }
 100    _mesa_init_instructions(p->Instructions, 2);
 101    /* MOV result.color, fragment.color; */
 102    p->Instructions[0].Opcode = OPCODE_MOV;
 103    p->Instructions[0].DstReg.File = PROGRAM_OUTPUT;
 104    p->Instructions[0].DstReg.Index = FRAG_RESULT_COLR;
 105    p->Instructions[0].SrcReg[0].File = PROGRAM_INPUT;
 106    p->Instructions[0].SrcReg[0].Index = FRAG_ATTRIB_COL0;
 107    /* END; */
 108    p->Instructions[1].Opcode = OPCODE_END;
 109
 110    p->InputsRead = FRAG_BIT_COL0;
 111    p->OutputsWritten = (1 << FRAG_RESULT_COLR);
 112
 113    stfp = (struct st_fragment_program *) p;
 114    st_translate_fragment_program(st, stfp, NULL);
 115
 116    return stfp;
 117 }
 118
 119
 120 /**
 121  * Create a simple vertex shader that just passes through the
 122  * vertex position and color.
 123  */
 124 static struct st_vertex_program *
 125 make_vertex_shader(struct st_context *st)
 126 {
 127    GLcontext *ctx = st->ctx;
 128    struct st_vertex_program *stvp;
 129    struct gl_program *p;
 130
 131    p = ctx->Driver.NewProgram(ctx, GL_VERTEX_PROGRAM_ARB, 0);
 132    if (!p)
 133       return NULL;
 134
 135    p->NumInstructions = 3;
 136    p->Instructions = _mesa_alloc_instructions(3);
 137    if (!p->Instructions) {
 138       ctx->Driver.DeleteProgram(ctx, p);
 139       return NULL;
 140    }
 141    _mesa_init_instructions(p->Instructions, 3);
 142    /* MOV result.pos, vertex.pos; */
 143    p->Instructions[0].Opcode = OPCODE_MOV;
 144    p->Instructions[0].DstReg.File = PROGRAM_OUTPUT;
 145    p->Instructions[0].DstReg.Index = VERT_RESULT_HPOS;
 146    p->Instructions[0].SrcReg[0].File = PROGRAM_INPUT;
 147    p->Instructions[0].SrcReg[0].Index = VERT_ATTRIB_POS;
 148    /* MOV result.color, vertex.color; */
 149    p->Instructions[1].Opcode = OPCODE_MOV;
 150    p->Instructions[1].DstReg.File = PROGRAM_OUTPUT;
 151    p->Instructions[1].DstReg.Index = VERT_RESULT_COL0;
 152    p->Instructions[1].SrcReg[0].File = PROGRAM_INPUT;
 153    p->Instructions[1].SrcReg[0].Index = VERT_ATTRIB_COLOR0;
 154    /* END; */
 155    p->Instructions[2].Opcode = OPCODE_END;
 156
 157    p->InputsRead = VERT_BIT_POS | VERT_BIT_COLOR0;
 158    p->OutputsWritten = ((1 << VERT_RESULT_COL0) |
 159                         (1 << VERT_RESULT_HPOS));
 160
 161    stvp = (struct st_vertex_program *) p;
 162    st_translate_vertex_program(st, stvp, NULL);
 163 #if 0
 164    assert(stvp->cso);
 165 #endif
 166
 167    return stvp;
 168 }
 169
 170
 171
 172 /**
 173  * Draw a screen-aligned quadrilateral.
 174  * Coords are window coords with y=0=bottom.  These coords will be transformed
 175  * by the vertex shader and viewport transform (which will flip Y if needed).
 176  */
 177 static void
 178 draw_quad(GLcontext *ctx,
 179           float x0, float y0, float x1, float y1, GLfloat z,
 180           const GLfloat color[4])
 181 {
 182    GLfloat verts[4][2][4]; /* four verts, two attribs, XYZW */
 183    GLuint i;
 184
 185 #if TEST_DRAW_PASSTHROUGH
 186    /* invert Y coords (may be off by one pixel) */
 187    y0 = ctx->DrawBuffer->Height - y0;
 188    y1 = ctx->DrawBuffer->Height - y1;
 189 #endif
 190
 191    /* positions */
 192    verts[0][0][0] = x0;
 193    verts[0][0][1] = y0;
 194
 195    verts[1][0][0] = x1;
 196    verts[1][0][1] = y0;
 197
 198    verts[2][0][0] = x1;
 199    verts[2][0][1] = y1;
 200
 201    verts[3][0][0] = x0;
 202    verts[3][0][1] = y1;
 203
 204    /* same for all verts: */
 205    for (i = 0; i < 4; i++) {
 206       verts[i][0][2] = z;
 207       verts[i][0][3] = 1.0;
 208       verts[i][1][0] = color[0];
 209       verts[i][1][1] = color[1];
 210       verts[i][1][2] = color[2];
 211       verts[i][1][3] = color[3];
 212    }
 213
 214    st_draw_vertices(ctx, PIPE_PRIM_POLYGON, 4, (float *) verts, 2,
 215 #if TEST_DRAW_PASSTHROUGH
 216                     GL_TRUE
 217 #else
 218                     GL_FALSE
 219 #endif
 220                     );
 221 }
 222
 223
 224
 225 /**
 226  * Do glClear by drawing a quadrilateral.
 227  * The vertices of the quad will be computed from the
 228  * ctx->DrawBuffer->_X/Ymin/max fields.
 229  */
 230 static void
 231 clear_with_quad(GLcontext *ctx,
 232                 GLboolean color, GLboolean depth, GLboolean stencil)
 233 {
 234    struct st_context *st = ctx->st;
 235    struct pipe_context *pipe = st->pipe;
 236    const GLfloat x0 = ctx->DrawBuffer->_Xmin;
 237    const GLfloat y0 = ctx->DrawBuffer->_Ymin;
 238    const GLfloat x1 = ctx->DrawBuffer->_Xmax;
 239    const GLfloat y1 = ctx->DrawBuffer->_Ymax;
 240
 241    /*
 242    printf("%s %s%s%s %f,%f %f,%f\n", __FUNCTION__,
 243           color ? "color, " : "",
 244           depth ? "depth, " : "",
 245           stencil ? "stencil" : "",
 246           x0, y0,
 247           x1, y1);
 248    */
 249
 250    cso_save_blend(st->cso_context);
 251    cso_save_depth_stencil_alpha(st->cso_context);
 252    cso_save_rasterizer(st->cso_context);
 253    cso_save_viewport(st->cso_context);
 254
 255    /* blend state: RGBA masking */
 256    {
 257       struct pipe_blend_state blend;
 258       memset(&blend, 0, sizeof(blend));
 259       blend.rgb_src_factor = PIPE_BLENDFACTOR_ONE;
 260       blend.alpha_src_factor = PIPE_BLENDFACTOR_ONE;
 261       blend.rgb_dst_factor = PIPE_BLENDFACTOR_ZERO;
 262       blend.alpha_dst_factor = PIPE_BLENDFACTOR_ZERO;
 263       if (color) {
 264          if (ctx->Color.ColorMask[0])
 265             blend.colormask |= PIPE_MASK_R;
 266          if (ctx->Color.ColorMask[1])
 267             blend.colormask |= PIPE_MASK_G;
 268          if (ctx->Color.ColorMask[2])
 269             blend.colormask |= PIPE_MASK_B;
 270          if (ctx->Color.ColorMask[3])
 271             blend.colormask |= PIPE_MASK_A;
 272          if (st->ctx->Color.DitherFlag)
 273             blend.dither = 1;
 274       }
 275       cso_set_blend(st->cso_context, &blend);
 276    }
 277
 278    /* depth_stencil state: always pass/set to ref value */
 279    {
 280       struct pipe_depth_stencil_alpha_state depth_stencil;
 281       memset(&depth_stencil, 0, sizeof(depth_stencil));
 282       if (depth) {
 283          depth_stencil.depth.enabled = 1;
 284          depth_stencil.depth.writemask = 1;
 285          depth_stencil.depth.func = PIPE_FUNC_ALWAYS;
 286       }
 287
 288       if (stencil) {
 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].ref_value = ctx->Stencil.Clear;
 295          depth_stencil.stencil[0].value_mask = 0xff;
 296          depth_stencil.stencil[0].write_mask = ctx->Stencil.WriteMask[0] & 0xff;
 297       }
 298
 299       cso_set_depth_stencil_alpha(st->cso_context, &depth_stencil);
 300    }
 301
 302    /* rasterizer state: nothing */
 303    {
 304       struct pipe_rasterizer_state raster;
 305       memset(&raster, 0, sizeof(raster));
 306 #if TEST_DRAW_PASSTHROUGH
 307       raster.bypass_clipping = 1;
 308       raster.bypass_vs = 1;
 309 #endif
 310       cso_set_rasterizer(st->cso_context, &raster);
 311    }
 312
 313    /* fragment shader state: color pass-through program */
 314    {
 315       static struct st_fragment_program *stfp = NULL;
 316       if (!stfp) {
 317          stfp = make_frag_shader(st);
 318       }
 319       pipe->bind_fs_state(pipe, stfp->driver_shader);
 320    }
 321
 322 #if !TEST_DRAW_PASSTHROUGH
 323    /* vertex shader state: color/position pass-through */
 324    {
 325       static struct st_vertex_program *stvp = NULL;
 326       if (!stvp) {
 327          stvp = make_vertex_shader(st);
 328       }
 329       pipe->bind_vs_state(pipe, stvp->driver_shader);
 330    }
 331 #endif
 332
 333 #if !TEST_DRAW_PASSTHROUGH
 334    /* viewport state: viewport matching window dims */
 335    {
 336       const float width = ctx->DrawBuffer->Width;
 337       const float height = ctx->DrawBuffer->Height;
 338       struct pipe_viewport_state vp;
 339       vp.scale[0] =  0.5 * width;
 340       vp.scale[1] = -0.5 * height;
 341       vp.scale[2] = 1.0;
 342       vp.scale[3] = 1.0;
 343       vp.translate[0] = 0.5 * width;
 344       vp.translate[1] = 0.5 * height;
 345       vp.translate[2] = 0.0;
 346       vp.translate[3] = 0.0;
 347       cso_set_viewport(st->cso_context, &vp);
 348    }
 349 #endif
 350
 351    /* draw quad matching scissor rect (XXX verify coord round-off) */
 352    draw_quad(ctx, x0, y0, x1, y1, ctx->Depth.Clear, ctx->Color.ClearColor);
 353
 354    /* Restore pipe state */
 355    cso_restore_blend(st->cso_context);
 356    cso_restore_depth_stencil_alpha(st->cso_context);
 357    cso_restore_rasterizer(st->cso_context);
 358    cso_restore_viewport(st->cso_context);
 359    /* these don't go through cso yet */
 360    pipe->bind_fs_state(pipe, st->fp->driver_shader);
 361    pipe->bind_vs_state(pipe, st->vp->driver_shader);
 362 }
 363
 364
 365 /**
 366  * Determine if we need to clear the depth buffer by drawing a quad.
 367  */
 368 static INLINE GLboolean
 369 check_clear_color_with_quad(GLcontext *ctx, struct gl_renderbuffer *rb)
 370 {
 371    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 372
 373    if (strb->surface->status == PIPE_SURFACE_STATUS_UNDEFINED)
 374       return FALSE;
 375
 376    if (ctx->Scissor.Enabled)
 377       return TRUE;
 378
 379    if (!ctx->Color.ColorMask[0] ||
 380        !ctx->Color.ColorMask[1] ||
 381        !ctx->Color.ColorMask[2] ||
 382        !ctx->Color.ColorMask[3])
 383       return TRUE;
 384
 385    return FALSE;
 386 }
 387
 388
 389 static INLINE GLboolean
 390 check_clear_depth_stencil_with_quad(GLcontext *ctx, struct gl_renderbuffer *rb)
 391 {
 392    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 393    const GLuint stencilMax = (1 << rb->StencilBits) - 1;
 394    GLboolean maskStencil
 395       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 396
 397    if (strb->surface->status == PIPE_SURFACE_STATUS_UNDEFINED)
 398       return FALSE;
 399
 400    if (ctx->Scissor.Enabled)
 401       return TRUE;
 402
 403    if (maskStencil)
 404       return TRUE;
 405
 406    return 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(GLcontext *ctx, struct gl_renderbuffer *rb)
 415 {
 416    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 417    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 418
 419    if (strb->surface->status == PIPE_SURFACE_STATUS_UNDEFINED)
 420       return FALSE;
 421
 422    if (ctx->Scissor.Enabled)
 423       return TRUE;
 424
 425    if (isDS &&
 426        strb->surface->status == PIPE_SURFACE_STATUS_DEFINED &&
 427        ctx->DrawBuffer->Visual.stencilBits > 0)
 428       return TRUE;
 429
 430    return 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(GLcontext *ctx, struct gl_renderbuffer *rb)
 439 {
 440    const struct st_renderbuffer *strb = st_renderbuffer(rb);
 441    const GLboolean isDS = is_depth_stencil_format(strb->surface->format);
 442    const GLuint stencilMax = (1 << rb->StencilBits) - 1;
 443    const GLboolean maskStencil
 444       = (ctx->Stencil.WriteMask[0] & stencilMax) != stencilMax;
 445
 446    if (strb->surface->status == PIPE_SURFACE_STATUS_UNDEFINED)
 447       return FALSE;
 448
 449    if (maskStencil)
 450       return TRUE;
 451
 452    if (ctx->Scissor.Enabled)
 453       return TRUE;
 454
 455    /* This is correct, but it is necessary to look at the depth clear
 456     * value held in the surface when it comes time to issue the clear,
 457     * rather than taking depth and stencil clear values from the
 458     * current state.
 459     */
 460    if (isDS &&
 461        strb->surface->status == PIPE_SURFACE_STATUS_DEFINED &&
 462        ctx->DrawBuffer->Visual.depthBits > 0)
 463       return TRUE;
 464
 465    return FALSE;
 466 }
 467
 468
 469
 470 static void
 471 clear_color_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 472 {
 473    if (check_clear_color_with_quad( ctx, rb )) {
 474       /* masking or scissoring */
 475       clear_with_quad(ctx, GL_TRUE, GL_FALSE, GL_FALSE);
 476    }
 477    else {
 478       /* clear whole buffer w/out masking */
 479       struct st_renderbuffer *strb = st_renderbuffer(rb);
 480       uint clearValue;
 481       util_pack_color(ctx->Color.ClearColor, strb->surface->format, &clearValue);
 482       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 483    }
 484 }
 485
 486
 487 static void
 488 clear_depth_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 489 {
 490    if (check_clear_depth_with_quad(ctx, rb)) {
 491       /* scissoring or we have a combined depth/stencil buffer */
 492       clear_with_quad(ctx, GL_FALSE, GL_TRUE, GL_FALSE);
 493    }
 494    else {
 495       struct st_renderbuffer *strb = st_renderbuffer(rb);
 496
 497       /* simple clear of whole buffer */
 498       uint clearValue = util_pack_z(strb->surface->format, ctx->Depth.Clear);
 499       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 500    }
 501 }
 502
 503
 504 static void
 505 clear_stencil_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 506 {
 507    if (check_clear_stencil_with_quad(ctx, rb)) {
 508       /* masking or scissoring or combined depth/stencil buffer */
 509       clear_with_quad(ctx, GL_FALSE, GL_FALSE, GL_TRUE);
 510    }
 511    else {
 512       struct st_renderbuffer *strb = st_renderbuffer(rb);
 513
 514       /* simple clear of whole buffer */
 515       GLuint clearValue = ctx->Stencil.Clear;
 516
 517       switch (strb->surface->format) {
 518       case PIPE_FORMAT_S8Z24_UNORM:
 519          clearValue <<= 24;
 520          break;
 521       default:
 522          ; /* no-op, stencil value is in least significant bits */
 523       }
 524
 525       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 526    }
 527 }
 528
 529
 530 static void
 531 clear_depth_stencil_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
 532 {
 533
 534    if (check_clear_depth_stencil_with_quad(ctx, rb)) {
 535       /* masking or scissoring */
 536       clear_with_quad(ctx, GL_FALSE, GL_TRUE, GL_TRUE);
 537    }
 538    else {
 539       struct st_renderbuffer *strb = st_renderbuffer(rb);
 540
 541       /* clear whole buffer w/out masking */
 542       GLuint clearValue = util_pack_z(strb->surface->format, ctx->Depth.Clear);
 543
 544       switch (strb->surface->format) {
 545       case PIPE_FORMAT_S8Z24_UNORM:
 546          clearValue |= ctx->Stencil.Clear << 24;
 547          break;
 548       case PIPE_FORMAT_Z24S8_UNORM:
 549          clearValue |= ctx->Stencil.Clear;
 550          break;
 551       default:
 552          assert(0);
 553       }
 554
 555       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
 556    }
 557 }
 558
 559
 560
 561 /**
 562  * Called via ctx->Driver.Clear()
 563  * XXX: doesn't pick up the differences between front/back/left/right
 564  * clears.  Need to sort that out...
 565  */
 566 static void st_clear(GLcontext *ctx, GLbitfield mask)
 567 {
 568    static const GLbitfield BUFFER_BITS_DS
 569       = (BUFFER_BIT_DEPTH | BUFFER_BIT_STENCIL);
 570    struct st_context *st = ctx->st;
 571    struct gl_renderbuffer *depthRb
 572       = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 573    struct gl_renderbuffer *stencilRb
 574       = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 575    GLbitfield cmask = mask & BUFFER_BITS_COLOR;
 576
 577    /* This makes sure the softpipe has the latest scissor, etc values */
 578    st_validate_state( st );
 579
 580    /*
 581     * XXX TO-DO:
 582     * If we're going to use clear_with_quad() for any reason, use it to
 583     * clear as many other buffers as possible.
 584     * As it is now, we sometimes call clear_with_quad() three times to clear
 585     * color/depth/stencil individually...
 586     */
 587
 588    if (cmask) {
 589       GLuint b;
 590       for (b = 0; cmask; b++) {
 591          if (cmask & (1 << b)) {
 592             struct gl_renderbuffer *rb
 593                = ctx->DrawBuffer->Attachment[b].Renderbuffer;
 594             assert(rb);
 595             clear_color_buffer(ctx, rb);
 596             cmask &= ~(1 << b); /* turn off bit */
 597          }
 598          assert(b < BUFFER_COUNT);
 599       }
 600    }
 601
 602    if (mask & BUFFER_BIT_ACCUM) {
 603       st_clear_accum_buffer(ctx,
 604                        ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer);
 605    }
 606
 607    if ((mask & BUFFER_BITS_DS) == BUFFER_BITS_DS && depthRb == stencilRb) {
 608       /* clearing combined depth + stencil */
 609       clear_depth_stencil_buffer(ctx, depthRb);
 610    }
 611    else {
 612       /* separate depth/stencil clears */
 613       if (mask & BUFFER_BIT_DEPTH) {
 614          clear_depth_buffer(ctx, depthRb);
 615       }
 616       if (mask & BUFFER_BIT_STENCIL) {
 617          clear_stencil_buffer(ctx, stencilRb);
 618       }
 619    }
 620 }
 621
 622
 623 void st_init_clear_functions(struct dd_function_table *functions)
 624 {
 625    functions->Clear = st_clear;
 626 }