src/gallium/drivers/llvmpipe/lp_bld_depth.c

   1 /**************************************************************************
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  13  *
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  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
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  27
  28 /**
  29  * @file
  30  * Depth/stencil testing to LLVM IR translation.
  31  *
  32  * To be done accurately/efficiently the depth/stencil test must be done with
  33  * the same type/format of the depth/stencil buffer, which implies massaging
  34  * the incoming depths to fit into place. Using a more straightforward
  35  * type/format for depth/stencil values internally and only convert when
  36  * flushing would avoid this, but it would most likely result in depth fighting
  37  * artifacts.
  38  *
  39  * We are free to use a different pixel layout though. Since our basic
  40  * processing unit is a quad (2x2 pixel block) we store the depth/stencil
  41  * values tiled, a quad at time. That is, a depth buffer containing
  42  *
  43  *  Z11 Z12 Z13 Z14 ...
  44  *  Z21 Z22 Z23 Z24 ...
  45  *  Z31 Z32 Z33 Z34 ...
  46  *  Z41 Z42 Z43 Z44 ...
  47  *  ... ... ... ... ...
  48  *
  49  * will actually be stored in memory as
  50  *
  51  *  Z11 Z12 Z21 Z22 Z13 Z14 Z23 Z24 ...
  52  *  Z31 Z32 Z41 Z42 Z33 Z34 Z43 Z44 ...
  53  *  ... ... ... ... ... ... ... ... ...
  54  *
  55  *
  56  * @author Jose Fonseca <jfonseca@vmware.com>
  57  * @author Brian Paul <jfonseca@vmware.com>
  58  */
  59
  60 #include "pipe/p_state.h"
  61 #include "util/u_format.h"
  62
  63 #include "gallivm/lp_bld_type.h"
  64 #include "gallivm/lp_bld_arit.h"
  65 #include "gallivm/lp_bld_bitarit.h"
  66 #include "gallivm/lp_bld_const.h"
  67 #include "gallivm/lp_bld_conv.h"
  68 #include "gallivm/lp_bld_logic.h"
  69 #include "gallivm/lp_bld_flow.h"
  70 #include "gallivm/lp_bld_intr.h"
  71 #include "gallivm/lp_bld_debug.h"
  72 #include "gallivm/lp_bld_swizzle.h"
  73
  74 #include "lp_bld_depth.h"
  75
  76
  77 /** Used to select fields from pipe_stencil_state */
  78 enum stencil_op {
  79    S_FAIL_OP,
  80    Z_FAIL_OP,
  81    Z_PASS_OP
  82 };
  83
  84
  85
  86 /**
  87  * Do the stencil test comparison (compare FB stencil values against ref value).
  88  * This will be used twice when generating two-sided stencil code.
  89  * \param stencil  the front/back stencil state
  90  * \param stencilRef  the stencil reference value, replicated as a vector
  91  * \param stencilVals  vector of stencil values from framebuffer
  92  * \return vector mask of pass/fail values (~0 or 0)
  93  */
  94 static LLVMValueRef
  95 lp_build_stencil_test_single(struct lp_build_context *bld,
  96                              const struct pipe_stencil_state *stencil,
  97                              LLVMValueRef stencilRef,
  98                              LLVMValueRef stencilVals)
  99 {
 100    const unsigned stencilMax = 255; /* XXX fix */
 101    struct lp_type type = bld->type;
 102    LLVMValueRef res;
 103
 104    assert(type.sign);
 105
 106    assert(stencil->enabled);
 107
 108    if (stencil->valuemask != stencilMax) {
 109       /* compute stencilRef = stencilRef & valuemask */
 110       LLVMValueRef valuemask = lp_build_const_int_vec(type, stencil->valuemask);
 111       stencilRef = LLVMBuildAnd(bld->builder, stencilRef, valuemask, "");
 112       /* compute stencilVals = stencilVals & valuemask */
 113       stencilVals = LLVMBuildAnd(bld->builder, stencilVals, valuemask, "");
 114    }
 115
 116    res = lp_build_cmp(bld, stencil->func, stencilRef, stencilVals);
 117
 118    return res;
 119 }
 120
 121
 122 /**
 123  * Do the one or two-sided stencil test comparison.
 124  * \sa lp_build_stencil_test_single
 125  * \param front_facing  an integer vector mask, indicating front (~0) or back
 126  *                      (0) facing polygon. If NULL, assume front-facing.
 127  */
 128 static LLVMValueRef
 129 lp_build_stencil_test(struct lp_build_context *bld,
 130                       const struct pipe_stencil_state stencil[2],
 131                       LLVMValueRef stencilRefs[2],
 132                       LLVMValueRef stencilVals,
 133                       LLVMValueRef front_facing)
 134 {
 135    LLVMValueRef res;
 136
 137    assert(stencil[0].enabled);
 138
 139    /* do front face test */
 140    res = lp_build_stencil_test_single(bld, &stencil[0],
 141                                       stencilRefs[0], stencilVals);
 142
 143    if (stencil[1].enabled && front_facing) {
 144       /* do back face test */
 145       LLVMValueRef back_res;
 146
 147       back_res = lp_build_stencil_test_single(bld, &stencil[1],
 148                                               stencilRefs[1], stencilVals);
 149
 150       res = lp_build_select(bld, front_facing, res, back_res);
 151    }
 152
 153    return res;
 154 }
 155
 156
 157 /**
 158  * Apply the stencil operator (add/sub/keep/etc) to the given vector
 159  * of stencil values.
 160  * \return  new stencil values vector
 161  */
 162 static LLVMValueRef
 163 lp_build_stencil_op_single(struct lp_build_context *bld,
 164                            const struct pipe_stencil_state *stencil,
 165                            enum stencil_op op,
 166                            LLVMValueRef stencilRef,
 167                            LLVMValueRef stencilVals)
 168
 169 {
 170    struct lp_type type = bld->type;
 171    LLVMValueRef res;
 172    LLVMValueRef max = lp_build_const_int_vec(type, 0xff);
 173    unsigned stencil_op;
 174
 175    assert(type.sign);
 176
 177    switch (op) {
 178    case S_FAIL_OP:
 179       stencil_op = stencil->fail_op;
 180       break;
 181    case Z_FAIL_OP:
 182       stencil_op = stencil->zfail_op;
 183       break;
 184    case Z_PASS_OP:
 185       stencil_op = stencil->zpass_op;
 186       break;
 187    default:
 188       assert(0 && "Invalid stencil_op mode");
 189       stencil_op = PIPE_STENCIL_OP_KEEP;
 190    }
 191
 192    switch (stencil_op) {
 193    case PIPE_STENCIL_OP_KEEP:
 194       res = stencilVals;
 195       /* we can return early for this case */
 196       return res;
 197    case PIPE_STENCIL_OP_ZERO:
 198       res = bld->zero;
 199       break;
 200    case PIPE_STENCIL_OP_REPLACE:
 201       res = stencilRef;
 202       break;
 203    case PIPE_STENCIL_OP_INCR:
 204       res = lp_build_add(bld, stencilVals, bld->one);
 205       res = lp_build_min(bld, res, max);
 206       break;
 207    case PIPE_STENCIL_OP_DECR:
 208       res = lp_build_sub(bld, stencilVals, bld->one);
 209       res = lp_build_max(bld, res, bld->zero);
 210       break;
 211    case PIPE_STENCIL_OP_INCR_WRAP:
 212       res = lp_build_add(bld, stencilVals, bld->one);
 213       res = LLVMBuildAnd(bld->builder, res, max, "");
 214       break;
 215    case PIPE_STENCIL_OP_DECR_WRAP:
 216       res = lp_build_sub(bld, stencilVals, bld->one);
 217       res = LLVMBuildAnd(bld->builder, res, max, "");
 218       break;
 219    case PIPE_STENCIL_OP_INVERT:
 220       res = LLVMBuildNot(bld->builder, stencilVals, "");
 221       res = LLVMBuildAnd(bld->builder, res, max, "");
 222       break;
 223    default:
 224       assert(0 && "bad stencil op mode");
 225       res = bld->undef;
 226    }
 227
 228    return res;
 229 }
 230
 231
 232 /**
 233  * Do the one or two-sided stencil test op/update.
 234  */
 235 static LLVMValueRef
 236 lp_build_stencil_op(struct lp_build_context *bld,
 237                     const struct pipe_stencil_state stencil[2],
 238                     enum stencil_op op,
 239                     LLVMValueRef stencilRefs[2],
 240                     LLVMValueRef stencilVals,
 241                     LLVMValueRef mask,
 242                     LLVMValueRef front_facing)
 243
 244 {
 245    LLVMValueRef res;
 246
 247    assert(stencil[0].enabled);
 248
 249    /* do front face op */
 250    res = lp_build_stencil_op_single(bld, &stencil[0], op,
 251                                      stencilRefs[0], stencilVals);
 252
 253    if (stencil[1].enabled && front_facing) {
 254       /* do back face op */
 255       LLVMValueRef back_res;
 256
 257       back_res = lp_build_stencil_op_single(bld, &stencil[1], op,
 258                                             stencilRefs[1], stencilVals);
 259
 260       res = lp_build_select(bld, front_facing, res, back_res);
 261    }
 262
 263    if (stencil->writemask != 0xff) {
 264       /* mask &= stencil->writemask */
 265       LLVMValueRef writemask = lp_build_const_int_vec(bld->type, stencil->writemask);
 266       mask = LLVMBuildAnd(bld->builder, mask, writemask, "");
 267       /* res = (res & mask) | (stencilVals & ~mask) */
 268       res = lp_build_select_bitwise(bld, writemask, res, stencilVals);
 269    }
 270    else {
 271       /* res = mask ? res : stencilVals */
 272       res = lp_build_select(bld, mask, res, stencilVals);
 273    }
 274
 275    return res;
 276 }
 277
 278
 279
 280 /**
 281  * Return a type appropriate for depth/stencil testing.
 282  */
 283 struct lp_type
 284 lp_depth_type(const struct util_format_description *format_desc,
 285               unsigned length)
 286 {
 287    struct lp_type type;
 288    unsigned swizzle;
 289
 290    assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
 291    assert(format_desc->block.width == 1);
 292    assert(format_desc->block.height == 1);
 293
 294    swizzle = format_desc->swizzle[0];
 295    assert(swizzle < 4);
 296
 297    memset(&type, 0, sizeof type);
 298    type.width = format_desc->block.bits;
 299
 300    if(format_desc->channel[swizzle].type == UTIL_FORMAT_TYPE_FLOAT) {
 301       type.floating = TRUE;
 302       assert(swizzle == 0);
 303       assert(format_desc->channel[swizzle].size == format_desc->block.bits);
 304    }
 305    else if(format_desc->channel[swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED) {
 306       assert(format_desc->block.bits <= 32);
 307       assert(format_desc->channel[swizzle].normalized);
 308       if (format_desc->channel[swizzle].size < format_desc->block.bits) {
 309          /* Prefer signed integers when possible, as SSE has less support
 310           * for unsigned comparison;
 311           */
 312          type.sign = TRUE;
 313       }
 314    }
 315    else
 316       assert(0);
 317
 318    assert(type.width <= length);
 319    type.length = length / type.width;
 320
 321    return type;
 322 }
 323
 324
 325 /**
 326  * Compute bitmask and bit shift to apply to the incoming fragment Z values
 327  * and the Z buffer values needed before doing the Z comparison.
 328  *
 329  * Note that we leave the Z bits in the position that we find them
 330  * in the Z buffer (typically 0xffffff00 or 0x00ffffff).  That lets us
 331  * get by with fewer bit twiddling steps.
 332  */
 333 static boolean
 334 get_z_shift_and_mask(const struct util_format_description *format_desc,
 335                      unsigned *shift, unsigned *width, unsigned *mask)
 336 {
 337    const unsigned total_bits = format_desc->block.bits;
 338    unsigned z_swizzle;
 339    unsigned chan;
 340    unsigned padding_left, padding_right;
 341
 342    assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
 343    assert(format_desc->block.width == 1);
 344    assert(format_desc->block.height == 1);
 345
 346    z_swizzle = format_desc->swizzle[0];
 347
 348    if (z_swizzle == UTIL_FORMAT_SWIZZLE_NONE)
 349       return FALSE;
 350
 351    *width = format_desc->channel[z_swizzle].size;
 352
 353    padding_right = 0;
 354    for (chan = 0; chan < z_swizzle; ++chan)
 355       padding_right += format_desc->channel[chan].size;
 356
 357    padding_left =
 358       total_bits - (padding_right + *width);
 359
 360    if (padding_left || padding_right) {
 361       unsigned long long mask_left = (1ULL << (total_bits - padding_left)) - 1;
 362       unsigned long long mask_right = (1ULL << (padding_right)) - 1;
 363       *mask = mask_left ^ mask_right;
 364    }
 365    else {
 366       *mask = 0xffffffff;
 367    }
 368
 369    *shift = padding_right;
 370
 371    return TRUE;
 372 }
 373
 374
 375 /**
 376  * Compute bitmask and bit shift to apply to the framebuffer pixel values
 377  * to put the stencil bits in the least significant position.
 378  * (i.e. 0x000000ff)
 379  */
 380 static boolean
 381 get_s_shift_and_mask(const struct util_format_description *format_desc,
 382                      unsigned *shift, unsigned *mask)
 383 {
 384    unsigned s_swizzle;
 385    unsigned chan, sz;
 386
 387    s_swizzle = format_desc->swizzle[1];
 388
 389    if (s_swizzle == UTIL_FORMAT_SWIZZLE_NONE)
 390       return FALSE;
 391
 392    *shift = 0;
 393    for (chan = 0; chan < s_swizzle; chan++)
 394       *shift += format_desc->channel[chan].size;
 395
 396    sz = format_desc->channel[s_swizzle].size;
 397    *mask = (1U << sz) - 1U;
 398
 399    return TRUE;
 400 }
 401
 402
 403 /**
 404  * Perform the occlusion test and increase the counter.
 405  * Test the depth mask. Add the number of channel which has none zero mask
 406  * into the occlusion counter. e.g. maskvalue is {-1, -1, -1, -1}.
 407  * The counter will add 4.
 408  *
 409  * \param type holds element type of the mask vector.
 410  * \param maskvalue is the depth test mask.
 411  * \param counter is a pointer of the uint32 counter.
 412  */
 413 void
 414 lp_build_occlusion_count(LLVMBuilderRef builder,
 415                          struct lp_type type,
 416                          LLVMValueRef maskvalue,
 417                          LLVMValueRef counter)
 418 {
 419    LLVMValueRef countmask = lp_build_const_int_vec(type, 1);
 420    LLVMValueRef countv = LLVMBuildAnd(builder, maskvalue, countmask, "countv");
 421    LLVMTypeRef i8v16 = LLVMVectorType(LLVMInt8Type(), 16);
 422    LLVMValueRef counti = LLVMBuildBitCast(builder, countv, i8v16, "counti");
 423    LLVMValueRef maskarray[4] = {
 424       LLVMConstInt(LLVMInt32Type(), 0, 0),
 425       LLVMConstInt(LLVMInt32Type(), 4, 0),
 426       LLVMConstInt(LLVMInt32Type(), 8, 0),
 427       LLVMConstInt(LLVMInt32Type(), 12, 0),
 428    };
 429    LLVMValueRef shufflemask = LLVMConstVector(maskarray, 4);
 430    LLVMValueRef shufflev =  LLVMBuildShuffleVector(builder, counti, LLVMGetUndef(i8v16), shufflemask, "shufflev");
 431    LLVMValueRef shuffle = LLVMBuildBitCast(builder, shufflev, LLVMInt32Type(), "shuffle");
 432    LLVMValueRef count = lp_build_intrinsic_unary(builder, "llvm.ctpop.i32", LLVMInt32Type(), shuffle);
 433    LLVMValueRef orig = LLVMBuildLoad(builder, counter, "orig");
 434    LLVMValueRef incr = LLVMBuildAdd(builder, orig, count, "incr");
 435    LLVMBuildStore(builder, incr, counter);
 436 }
 437
 438
 439
 440 /**
 441  * Generate code for performing depth and/or stencil tests.
 442  * We operate on a vector of values (typically a 2x2 quad).
 443  *
 444  * \param depth  the depth test state
 445  * \param stencil  the front/back stencil state
 446  * \param type  the data type of the fragment depth/stencil values
 447  * \param format_desc  description of the depth/stencil surface
 448  * \param mask  the alive/dead pixel mask for the quad (vector)
 449  * \param stencil_refs  the front/back stencil ref values (scalar)
 450  * \param z_src  the incoming depth/stencil values (a 2x2 quad, float32)
 451  * \param zs_dst_ptr  pointer to depth/stencil values in framebuffer
 452  * \param facing  contains boolean value indicating front/back facing polygon
 453  */
 454 void
 455 lp_build_depth_stencil_test(LLVMBuilderRef builder,
 456                             const struct pipe_depth_state *depth,
 457                             const struct pipe_stencil_state stencil[2],
 458                             struct lp_type z_src_type,
 459                             const struct util_format_description *format_desc,
 460                             struct lp_build_mask_context *mask,
 461                             LLVMValueRef stencil_refs[2],
 462                             LLVMValueRef z_src,
 463                             LLVMValueRef zs_dst_ptr,
 464                             LLVMValueRef face,
 465                             LLVMValueRef *zs_value,
 466                             boolean do_branch)
 467 {
 468    struct lp_type z_type;
 469    struct lp_build_context z_bld;
 470    struct lp_build_context s_bld;
 471    struct lp_type s_type;
 472    unsigned z_shift = 0, z_width = 0, z_mask = 0;
 473    LLVMValueRef zs_dst, z_dst = NULL;
 474    LLVMValueRef stencil_vals = NULL;
 475    LLVMValueRef z_bitmask = NULL, stencil_shift = NULL;
 476    LLVMValueRef z_pass = NULL, s_pass_mask = NULL;
 477    LLVMValueRef orig_mask = lp_build_mask_value(mask);
 478    LLVMValueRef front_facing = NULL;
 479
 480
 481    /*
 482     * Depths are expected to be between 0 and 1, even if they are stored in
 483     * floats. Setting these bits here will ensure that the lp_build_conv() call
 484     * below won't try to unnecessarily clamp the incoming values.
 485     */
 486    if(z_src_type.floating) {
 487       z_src_type.sign = FALSE;
 488       z_src_type.norm = TRUE;
 489    }
 490    else {
 491       assert(!z_src_type.sign);
 492       assert(z_src_type.norm);
 493    }
 494
 495    /* Pick the depth type. */
 496    z_type = lp_depth_type(format_desc, z_src_type.width*z_src_type.length);
 497
 498    /* FIXME: Cope with a depth test type with a different bit width. */
 499    assert(z_type.width == z_src_type.width);
 500    assert(z_type.length == z_src_type.length);
 501
 502    /* Sanity checking */
 503    {
 504       const unsigned z_swizzle = format_desc->swizzle[0];
 505       const unsigned s_swizzle = format_desc->swizzle[1];
 506
 507       assert(z_swizzle != UTIL_FORMAT_SWIZZLE_NONE ||
 508              s_swizzle != UTIL_FORMAT_SWIZZLE_NONE);
 509
 510       assert(depth->enabled || stencil[0].enabled);
 511
 512       assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
 513       assert(format_desc->block.width == 1);
 514       assert(format_desc->block.height == 1);
 515
 516       if (stencil[0].enabled) {
 517          assert(format_desc->format == PIPE_FORMAT_Z24_UNORM_S8_USCALED ||
 518                 format_desc->format == PIPE_FORMAT_S8_USCALED_Z24_UNORM);
 519       }
 520
 521       assert(z_swizzle < 4);
 522       assert(format_desc->block.bits == z_type.width);
 523       if (z_type.floating) {
 524          assert(z_swizzle == 0);
 525          assert(format_desc->channel[z_swizzle].type ==
 526                 UTIL_FORMAT_TYPE_FLOAT);
 527          assert(format_desc->channel[z_swizzle].size ==
 528                 format_desc->block.bits);
 529       }
 530       else {
 531          assert(format_desc->channel[z_swizzle].type ==
 532                 UTIL_FORMAT_TYPE_UNSIGNED);
 533          assert(format_desc->channel[z_swizzle].normalized);
 534          assert(!z_type.fixed);
 535       }
 536    }
 537
 538
 539    /* Setup build context for Z vals */
 540    lp_build_context_init(&z_bld, builder, z_type);
 541
 542    /* Setup build context for stencil vals */
 543    s_type = lp_type_int_vec(z_type.width);
 544    lp_build_context_init(&s_bld, builder, s_type);
 545
 546    /* Load current z/stencil value from z/stencil buffer */
 547    zs_dst_ptr = LLVMBuildBitCast(builder,
 548                                  zs_dst_ptr,
 549                                  LLVMPointerType(z_bld.vec_type, 0), "");
 550    zs_dst = LLVMBuildLoad(builder, zs_dst_ptr, "");
 551
 552    lp_build_name(zs_dst, "zs_dst");
 553
 554
 555    /* Compute and apply the Z/stencil bitmasks and shifts.
 556     */
 557    {
 558       unsigned s_shift, s_mask;
 559
 560       if (get_z_shift_and_mask(format_desc, &z_shift, &z_width, &z_mask)) {
 561          if (z_mask != 0xffffffff) {
 562             z_bitmask = lp_build_const_int_vec(z_type, z_mask);
 563          }
 564
 565          /*
 566           * Align the framebuffer Z 's LSB to the right.
 567           */
 568          if (z_shift) {
 569             LLVMValueRef shift = lp_build_const_int_vec(z_type, z_shift);
 570             z_dst = LLVMBuildLShr(builder, zs_dst, shift, "z_dst");
 571          } else if (z_bitmask) {
 572             /* TODO: Instead of loading a mask from memory and ANDing, it's
 573              * probably faster to just shake the bits with two shifts. */
 574             z_dst = LLVMBuildAnd(builder, zs_dst, z_bitmask, "z_dst");
 575          } else {
 576             z_dst = zs_dst;
 577             lp_build_name(z_dst, "z_dst");
 578          }
 579       }
 580
 581       if (get_s_shift_and_mask(format_desc, &s_shift, &s_mask)) {
 582          if (s_shift) {
 583             LLVMValueRef shift = lp_build_const_int_vec(s_type, s_shift);
 584             stencil_vals = LLVMBuildLShr(builder, zs_dst, shift, "");
 585             stencil_shift = shift;  /* used below */
 586          }
 587          else {
 588             stencil_vals = zs_dst;
 589          }
 590
 591          if (s_mask != 0xffffffff) {
 592             LLVMValueRef mask = lp_build_const_int_vec(s_type, s_mask);
 593             stencil_vals = LLVMBuildAnd(builder, stencil_vals, mask, "");
 594          }
 595
 596          lp_build_name(stencil_vals, "s_dst");
 597       }
 598    }
 599
 600    if (stencil[0].enabled) {
 601
 602       if (face) {
 603          LLVMValueRef zero = LLVMConstInt(LLVMInt32Type(), 0, 0);
 604
 605          /* front_facing = face != 0 ? ~0 : 0 */
 606          front_facing = LLVMBuildICmp(builder, LLVMIntNE, face, zero, "");
 607          front_facing = LLVMBuildSExt(builder, front_facing,
 608                                       LLVMIntType(s_bld.type.length*s_bld.type.width),
 609                                       "");
 610          front_facing = LLVMBuildBitCast(builder, front_facing,
 611                                          s_bld.int_vec_type, "");
 612       }
 613
 614       /* convert scalar stencil refs into vectors */
 615       stencil_refs[0] = lp_build_broadcast_scalar(&s_bld, stencil_refs[0]);
 616       stencil_refs[1] = lp_build_broadcast_scalar(&s_bld, stencil_refs[1]);
 617
 618       s_pass_mask = lp_build_stencil_test(&s_bld, stencil,
 619                                           stencil_refs, stencil_vals,
 620                                           front_facing);
 621
 622       /* apply stencil-fail operator */
 623       {
 624          LLVMValueRef s_fail_mask = lp_build_andnot(&s_bld, orig_mask, s_pass_mask);
 625          stencil_vals = lp_build_stencil_op(&s_bld, stencil, S_FAIL_OP,
 626                                             stencil_refs, stencil_vals,
 627                                             s_fail_mask, front_facing);
 628       }
 629    }
 630
 631    if (depth->enabled) {
 632       /*
 633        * Convert fragment Z to the desired type, aligning the LSB to the right.
 634        */
 635
 636       assert(z_type.width == z_src_type.width);
 637       assert(z_type.length == z_src_type.length);
 638       assert(lp_check_value(z_src_type, z_src));
 639       if (z_src_type.floating) {
 640          /*
 641           * Convert from floating point values
 642           */
 643
 644          if (!z_type.floating) {
 645             z_src = lp_build_clamped_float_to_unsigned_norm(builder,
 646                                                             z_src_type,
 647                                                             z_width,
 648                                                             z_src);
 649          }
 650       } else {
 651          /*
 652           * Convert from unsigned normalized values.
 653           */
 654
 655          assert(!z_src_type.sign);
 656          assert(!z_src_type.fixed);
 657          assert(z_src_type.norm);
 658          assert(!z_type.floating);
 659          if (z_src_type.width > z_width) {
 660             LLVMValueRef shift = lp_build_const_int_vec(z_src_type,
 661                                                         z_src_type.width - z_width);
 662             z_src = LLVMBuildLShr(builder, z_src, shift, "");
 663          }
 664       }
 665       assert(lp_check_value(z_type, z_src));
 666
 667       lp_build_name(z_src, "z_src");
 668
 669       /* compare src Z to dst Z, returning 'pass' mask */
 670       z_pass = lp_build_cmp(&z_bld, depth->func, z_src, z_dst);
 671
 672       if (!stencil[0].enabled) {
 673          /* We can potentially skip all remaining operations here, but only
 674           * if stencil is disabled because we still need to update the stencil
 675           * buffer values.  Don't need to update Z buffer values.
 676           */
 677          lp_build_mask_update(mask, z_pass);
 678
 679          if (do_branch) {
 680             lp_build_mask_check(mask);
 681             do_branch = FALSE;
 682          }
 683       }
 684
 685       if (depth->writemask) {
 686          LLVMValueRef zselectmask;
 687
 688          /* mask off bits that failed Z test */
 689          zselectmask = LLVMBuildAnd(builder, orig_mask, z_pass, "");
 690
 691          /* mask off bits that failed stencil test */
 692          if (s_pass_mask) {
 693             zselectmask = LLVMBuildAnd(builder, zselectmask, s_pass_mask, "");
 694          }
 695
 696          /* Mix the old and new Z buffer values.
 697           * z_dst[i] = zselectmask[i] ? z_src[i] : z_dst[i]
 698           */
 699          z_dst = lp_build_select(&z_bld, zselectmask, z_src, z_dst);
 700       }
 701
 702       if (stencil[0].enabled) {
 703          /* update stencil buffer values according to z pass/fail result */
 704          LLVMValueRef z_fail_mask, z_pass_mask;
 705
 706          /* apply Z-fail operator */
 707          z_fail_mask = lp_build_andnot(&z_bld, orig_mask, z_pass);
 708          stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_FAIL_OP,
 709                                             stencil_refs, stencil_vals,
 710                                             z_fail_mask, front_facing);
 711
 712          /* apply Z-pass operator */
 713          z_pass_mask = LLVMBuildAnd(z_bld.builder, orig_mask, z_pass, "");
 714          stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
 715                                             stencil_refs, stencil_vals,
 716                                             z_pass_mask, front_facing);
 717       }
 718    }
 719    else {
 720       /* No depth test: apply Z-pass operator to stencil buffer values which
 721        * passed the stencil test.
 722        */
 723       s_pass_mask = LLVMBuildAnd(s_bld.builder, orig_mask, s_pass_mask, "");
 724       stencil_vals = lp_build_stencil_op(&s_bld, stencil, Z_PASS_OP,
 725                                          stencil_refs, stencil_vals,
 726                                          s_pass_mask, front_facing);
 727    }
 728
 729    /* Put Z and ztencil bits in the right place */
 730    if (z_dst && z_shift) {
 731       LLVMValueRef shift = lp_build_const_int_vec(z_type, z_shift);
 732       z_dst = LLVMBuildShl(builder, z_dst, shift, "");
 733    }
 734    if (stencil_vals && stencil_shift)
 735       stencil_vals = LLVMBuildShl(s_bld.builder, stencil_vals,
 736                                   stencil_shift, "");
 737
 738    /* Finally, merge/store the z/stencil values */
 739    if ((depth->enabled && depth->writemask) ||
 740        (stencil[0].enabled && stencil[0].writemask)) {
 741
 742       if (z_dst && stencil_vals)
 743          zs_dst = LLVMBuildOr(z_bld.builder, z_dst, stencil_vals, "");
 744       else if (z_dst)
 745          zs_dst = z_dst;
 746       else
 747          zs_dst = stencil_vals;
 748
 749       *zs_value = zs_dst;
 750    }
 751
 752    if (s_pass_mask)
 753       lp_build_mask_update(mask, s_pass_mask);
 754
 755    if (depth->enabled && stencil[0].enabled)
 756       lp_build_mask_update(mask, z_pass);
 757
 758    if (do_branch)
 759       lp_build_mask_check(mask);
 760
 761 }
 762
 763
 764 void
 765 lp_build_depth_write(LLVMBuilderRef builder,
 766                      const struct util_format_description *format_desc,
 767                      LLVMValueRef zs_dst_ptr,
 768                      LLVMValueRef zs_value)
 769 {
 770    zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr,
 771                                  LLVMPointerType(LLVMTypeOf(zs_value), 0), "");
 772
 773    LLVMBuildStore(builder, zs_value, zs_dst_ptr);
 774 }
 775
 776
 777 void
 778 lp_build_deferred_depth_write(LLVMBuilderRef builder,
 779                               struct lp_type z_src_type,
 780                               const struct util_format_description *format_desc,
 781                               struct lp_build_mask_context *mask,
 782                               LLVMValueRef zs_dst_ptr,
 783                               LLVMValueRef zs_value)
 784 {
 785    struct lp_type z_type;
 786    struct lp_build_context z_bld;
 787    LLVMValueRef z_dst;
 788
 789    /* XXX: pointlessly redo type logic:
 790     */
 791    z_type = lp_depth_type(format_desc, z_src_type.width*z_src_type.length);
 792    lp_build_context_init(&z_bld, builder, z_type);
 793
 794    zs_dst_ptr = LLVMBuildBitCast(builder, zs_dst_ptr,
 795                                  LLVMPointerType(z_bld.vec_type, 0), "");
 796
 797    z_dst = LLVMBuildLoad(builder, zs_dst_ptr, "zsbufval");
 798    z_dst = lp_build_select(&z_bld, lp_build_mask_value(mask), zs_value, z_dst);
 799
 800    LLVMBuildStore(builder, z_dst, zs_dst_ptr);
 801 }