1 /**************************************************************************
3 * Copyright 2009 VMware, Inc.
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:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
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 VMWARE 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.
26 **************************************************************************/
30 * Depth/stencil testing to LLVM IR translation.
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
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
49 * will actually be stored in memory as
51 * Z11 Z12 Z21 Z22 Z13 Z14 Z23 Z24 ...
52 * Z31 Z32 Z41 Z42 Z33 Z34 Z43 Z44 ...
53 * ... ... ... ... ... ... ... ... ...
57 * Two-sided stencil test is supported but probably not as efficient as
58 * it could be. Currently, we use if/then/else constructs to do the
59 * operations for front vs. back-facing polygons. We could probably do
60 * both the front and back arithmetic then use a Select() instruction to
61 * choose the result depending on polyon orientation. We'd have to
62 * measure performance both ways and see which is better.
64 * @author Jose Fonseca <jfonseca@vmware.com>
67 #include "pipe/p_state.h"
68 #include "util/u_format.h"
70 #include "gallivm/lp_bld_type.h"
71 #include "gallivm/lp_bld_arit.h"
72 #include "gallivm/lp_bld_const.h"
73 #include "gallivm/lp_bld_logic.h"
74 #include "gallivm/lp_bld_flow.h"
75 #include "gallivm/lp_bld_debug.h"
76 #include "gallivm/lp_bld_swizzle.h"
78 #include "lp_bld_depth.h"
81 /** Used to select fields from pipe_stencil_state */
91 * Do the stencil test comparison (compare FB stencil values against ref value).
92 * This will be used twice when generating two-sided stencil code.
93 * \param stencil the front/back stencil state
94 * \param stencilRef the stencil reference value, replicated as a vector
95 * \param stencilVals vector of stencil values from framebuffer
96 * \return vector mask of pass/fail values (~0 or 0)
99 lp_build_stencil_test_single(struct lp_build_context
*bld
,
100 const struct pipe_stencil_state
*stencil
,
101 LLVMValueRef stencilRef
,
102 LLVMValueRef stencilVals
)
104 const unsigned stencilMax
= 255; /* XXX fix */
105 struct lp_type type
= bld
->type
;
110 assert(stencil
->enabled
);
112 if (stencil
->valuemask
!= stencilMax
) {
113 /* compute stencilRef = stencilRef & valuemask */
114 LLVMValueRef valuemask
= lp_build_const_int_vec(type
, stencil
->valuemask
);
115 stencilRef
= LLVMBuildAnd(bld
->builder
, stencilRef
, valuemask
, "");
116 /* compute stencilVals = stencilVals & valuemask */
117 stencilVals
= LLVMBuildAnd(bld
->builder
, stencilVals
, valuemask
, "");
120 res
= lp_build_cmp(bld
, stencil
->func
, stencilRef
, stencilVals
);
127 * Do the one or two-sided stencil test comparison.
128 * \sa lp_build_stencil_test_single
129 * \param face an integer indicating front (+) or back (-) facing polygon.
130 * If NULL, assume front-facing.
133 lp_build_stencil_test(struct lp_build_context
*bld
,
134 const struct pipe_stencil_state stencil
[2],
135 LLVMValueRef stencilRefs
[2],
136 LLVMValueRef stencilVals
,
141 assert(stencil
[0].enabled
);
143 if (stencil
[1].enabled
&& face
) {
144 /* do two-sided test */
145 struct lp_build_flow_context
*flow_ctx
;
146 struct lp_build_if_state if_ctx
;
147 LLVMValueRef front_facing
;
148 LLVMValueRef zero
= LLVMConstReal(LLVMFloatType(), 0.0);
149 LLVMValueRef result
= bld
->undef
;
151 flow_ctx
= lp_build_flow_create(bld
->builder
);
152 lp_build_flow_scope_begin(flow_ctx
);
154 lp_build_flow_scope_declare(flow_ctx
, &result
);
156 /* front_facing = face > 0.0 */
157 front_facing
= LLVMBuildFCmp(bld
->builder
, LLVMRealUGT
, face
, zero
, "");
159 lp_build_if(&if_ctx
, flow_ctx
, bld
->builder
, front_facing
);
161 result
= lp_build_stencil_test_single(bld
, &stencil
[0],
162 stencilRefs
[0], stencilVals
);
164 lp_build_else(&if_ctx
);
166 result
= lp_build_stencil_test_single(bld
, &stencil
[1],
167 stencilRefs
[1], stencilVals
);
169 lp_build_endif(&if_ctx
);
171 lp_build_flow_scope_end(flow_ctx
);
172 lp_build_flow_destroy(flow_ctx
);
177 /* do single-side test */
178 res
= lp_build_stencil_test_single(bld
, &stencil
[0],
179 stencilRefs
[0], stencilVals
);
187 * Apply the stencil operator (add/sub/keep/etc) to the given vector
189 * \return new stencil values vector
192 lp_build_stencil_op_single(struct lp_build_context
*bld
,
193 const struct pipe_stencil_state
*stencil
,
195 LLVMValueRef stencilRef
,
196 LLVMValueRef stencilVals
,
200 const unsigned stencilMax
= 255; /* XXX fix */
201 struct lp_type type
= bld
->type
;
203 LLVMValueRef max
= lp_build_const_int_vec(type
, stencilMax
);
210 stencil_op
= stencil
->fail_op
;
213 stencil_op
= stencil
->zfail_op
;
216 stencil_op
= stencil
->zpass_op
;
219 assert(0 && "Invalid stencil_op mode");
220 stencil_op
= PIPE_STENCIL_OP_KEEP
;
223 switch (stencil_op
) {
224 case PIPE_STENCIL_OP_KEEP
:
226 /* we can return early for this case */
228 case PIPE_STENCIL_OP_ZERO
:
231 case PIPE_STENCIL_OP_REPLACE
:
234 case PIPE_STENCIL_OP_INCR
:
235 res
= lp_build_add(bld
, stencilVals
, bld
->one
);
236 res
= lp_build_min(bld
, res
, max
);
238 case PIPE_STENCIL_OP_DECR
:
239 res
= lp_build_sub(bld
, stencilVals
, bld
->one
);
240 res
= lp_build_max(bld
, res
, bld
->zero
);
242 case PIPE_STENCIL_OP_INCR_WRAP
:
243 res
= lp_build_add(bld
, stencilVals
, bld
->one
);
244 res
= LLVMBuildAnd(bld
->builder
, res
, max
, "");
246 case PIPE_STENCIL_OP_DECR_WRAP
:
247 res
= lp_build_sub(bld
, stencilVals
, bld
->one
);
248 res
= LLVMBuildAnd(bld
->builder
, res
, max
, "");
250 case PIPE_STENCIL_OP_INVERT
:
251 res
= LLVMBuildNot(bld
->builder
, stencilVals
, "");
252 res
= LLVMBuildAnd(bld
->builder
, res
, max
, "");
255 assert(0 && "bad stencil op mode");
259 if (stencil
->writemask
!= stencilMax
) {
260 /* compute res = (res & mask) | (stencilVals & ~mask) */
261 LLVMValueRef mask
= lp_build_const_int_vec(type
, stencil
->writemask
);
262 LLVMValueRef cmask
= LLVMBuildNot(bld
->builder
, mask
, "notWritemask");
263 LLVMValueRef t1
= LLVMBuildAnd(bld
->builder
, res
, mask
, "t1");
264 LLVMValueRef t2
= LLVMBuildAnd(bld
->builder
, stencilVals
, cmask
, "t2");
265 res
= LLVMBuildOr(bld
->builder
, t1
, t2
, "t1_or_t2");
268 /* only the update the vector elements enabled by 'mask' */
269 res
= lp_build_select(bld
, mask
, res
, stencilVals
);
276 * Do the one or two-sided stencil test op/update.
279 lp_build_stencil_op(struct lp_build_context
*bld
,
280 const struct pipe_stencil_state stencil
[2],
282 LLVMValueRef stencilRefs
[2],
283 LLVMValueRef stencilVals
,
288 assert(stencil
[0].enabled
);
290 if (stencil
[1].enabled
&& face
) {
291 /* do two-sided op */
292 struct lp_build_flow_context
*flow_ctx
;
293 struct lp_build_if_state if_ctx
;
294 LLVMValueRef front_facing
;
295 LLVMValueRef zero
= LLVMConstReal(LLVMFloatType(), 0.0);
296 LLVMValueRef result
= bld
->undef
;
298 flow_ctx
= lp_build_flow_create(bld
->builder
);
299 lp_build_flow_scope_begin(flow_ctx
);
301 lp_build_flow_scope_declare(flow_ctx
, &result
);
303 /* front_facing = face > 0.0 */
304 front_facing
= LLVMBuildFCmp(bld
->builder
, LLVMRealUGT
, face
, zero
, "");
306 lp_build_if(&if_ctx
, flow_ctx
, bld
->builder
, front_facing
);
308 result
= lp_build_stencil_op_single(bld
, &stencil
[0], op
,
309 stencilRefs
[0], stencilVals
, mask
);
311 lp_build_else(&if_ctx
);
313 result
= lp_build_stencil_op_single(bld
, &stencil
[1], op
,
314 stencilRefs
[1], stencilVals
, mask
);
316 lp_build_endif(&if_ctx
);
318 lp_build_flow_scope_end(flow_ctx
);
319 lp_build_flow_destroy(flow_ctx
);
324 /* do single-sided op */
325 return lp_build_stencil_op_single(bld
, &stencil
[0], op
,
326 stencilRefs
[0], stencilVals
, mask
);
333 * Return a type appropriate for depth/stencil testing.
336 lp_depth_type(const struct util_format_description
*format_desc
,
342 assert(format_desc
->colorspace
== UTIL_FORMAT_COLORSPACE_ZS
);
343 assert(format_desc
->block
.width
== 1);
344 assert(format_desc
->block
.height
== 1);
346 swizzle
= format_desc
->swizzle
[0];
349 memset(&type
, 0, sizeof type
);
350 type
.width
= format_desc
->block
.bits
;
352 if(format_desc
->channel
[swizzle
].type
== UTIL_FORMAT_TYPE_FLOAT
) {
353 type
.floating
= TRUE
;
354 assert(swizzle
== 0);
355 assert(format_desc
->channel
[swizzle
].size
== format_desc
->block
.bits
);
357 else if(format_desc
->channel
[swizzle
].type
== UTIL_FORMAT_TYPE_UNSIGNED
) {
358 assert(format_desc
->block
.bits
<= 32);
359 if(format_desc
->channel
[swizzle
].normalized
)
365 assert(type
.width
<= length
);
366 type
.length
= length
/ type
.width
;
373 * Compute bitmask and bit shift to apply to the incoming fragment Z values
374 * and the Z buffer values needed before doing the Z comparison.
376 * Note that we leave the Z bits in the position that we find them
377 * in the Z buffer (typically 0xffffff00 or 0x00ffffff). That lets us
378 * get by with fewer bit twiddling steps.
381 get_z_shift_and_mask(const struct util_format_description
*format_desc
,
382 unsigned *shift
, unsigned *mask
)
384 const unsigned total_bits
= format_desc
->block
.bits
;
387 unsigned padding_left
, padding_right
;
389 assert(format_desc
->colorspace
== UTIL_FORMAT_COLORSPACE_ZS
);
390 assert(format_desc
->block
.width
== 1);
391 assert(format_desc
->block
.height
== 1);
393 z_swizzle
= format_desc
->swizzle
[0];
395 if (z_swizzle
== UTIL_FORMAT_SWIZZLE_NONE
)
399 for (chan
= 0; chan
< z_swizzle
; ++chan
)
400 padding_right
+= format_desc
->channel
[chan
].size
;
403 total_bits
- (padding_right
+ format_desc
->channel
[z_swizzle
].size
);
405 if (padding_left
|| padding_right
) {
406 unsigned long long mask_left
= (1ULL << (total_bits
- padding_left
)) - 1;
407 unsigned long long mask_right
= (1ULL << (padding_right
)) - 1;
408 *mask
= mask_left
^ mask_right
;
414 *shift
= padding_left
;
421 * Compute bitmask and bit shift to apply to the framebuffer pixel values
422 * to put the stencil bits in the least significant position.
426 get_s_shift_and_mask(const struct util_format_description
*format_desc
,
427 unsigned *shift
, unsigned *mask
)
432 s_swizzle
= format_desc
->swizzle
[1];
434 if (s_swizzle
== UTIL_FORMAT_SWIZZLE_NONE
)
438 for (chan
= 0; chan
< s_swizzle
; chan
++)
439 *shift
+= format_desc
->channel
[chan
].size
;
441 sz
= format_desc
->channel
[s_swizzle
].size
;
442 *mask
= (1U << sz
) - 1U;
450 * Generate code for performing depth and/or stencil tests.
451 * We operate on a vector of values (typically a 2x2 quad).
453 * \param depth the depth test state
454 * \param stencil the front/back stencil state
455 * \param type the data type of the fragment depth/stencil values
456 * \param format_desc description of the depth/stencil surface
457 * \param mask the alive/dead pixel mask for the quad (vector)
458 * \param stencil_refs the front/back stencil ref values (scalar)
459 * \param z_src the incoming depth/stencil values (a 2x2 quad)
460 * \param zs_dst_ptr pointer to depth/stencil values in framebuffer
461 * \param facing contains float value indicating front/back facing polygon
464 lp_build_depth_stencil_test(LLVMBuilderRef builder
,
465 const struct pipe_depth_state
*depth
,
466 const struct pipe_stencil_state stencil
[2],
468 const struct util_format_description
*format_desc
,
469 struct lp_build_mask_context
*mask
,
470 LLVMValueRef stencil_refs
[2],
472 LLVMValueRef zs_dst_ptr
,
475 struct lp_build_context bld
;
476 struct lp_build_context sbld
;
477 struct lp_type s_type
;
478 LLVMValueRef zs_dst
, z_dst
= NULL
;
479 LLVMValueRef stencil_vals
= NULL
;
480 LLVMValueRef z_bitmask
= NULL
, stencil_shift
= NULL
;
481 LLVMValueRef z_pass
= NULL
, s_pass_mask
= NULL
;
482 LLVMValueRef orig_mask
= mask
->value
;
484 /* Sanity checking */
486 const unsigned z_swizzle
= format_desc
->swizzle
[0];
487 const unsigned s_swizzle
= format_desc
->swizzle
[1];
489 assert(z_swizzle
!= UTIL_FORMAT_SWIZZLE_NONE
||
490 s_swizzle
!= UTIL_FORMAT_SWIZZLE_NONE
);
492 assert(depth
->enabled
|| stencil
[0].enabled
);
494 assert(format_desc
->colorspace
== UTIL_FORMAT_COLORSPACE_ZS
);
495 assert(format_desc
->block
.width
== 1);
496 assert(format_desc
->block
.height
== 1);
498 if (stencil
[0].enabled
) {
499 assert(format_desc
->format
== PIPE_FORMAT_Z24_UNORM_S8_USCALED
||
500 format_desc
->format
== PIPE_FORMAT_S8_USCALED_Z24_UNORM
);
503 assert(z_swizzle
< 4);
504 assert(format_desc
->block
.bits
== type
.width
);
506 assert(z_swizzle
== 0);
507 assert(format_desc
->channel
[z_swizzle
].type
==
508 UTIL_FORMAT_TYPE_FLOAT
);
509 assert(format_desc
->channel
[z_swizzle
].size
==
510 format_desc
->block
.bits
);
513 assert(format_desc
->channel
[z_swizzle
].type
==
514 UTIL_FORMAT_TYPE_UNSIGNED
);
515 assert(format_desc
->channel
[z_swizzle
].normalized
);
523 /* Setup build context for Z vals */
524 lp_build_context_init(&bld
, builder
, type
);
526 /* Setup build context for stencil vals */
527 s_type
= lp_type_int_vec(type
.width
);
528 lp_build_context_init(&sbld
, builder
, s_type
);
530 /* Load current z/stencil value from z/stencil buffer */
531 zs_dst
= LLVMBuildLoad(builder
, zs_dst_ptr
, "");
533 lp_build_name(zs_dst
, "zsbufval");
536 /* Compute and apply the Z/stencil bitmasks and shifts.
539 unsigned z_shift
, z_mask
;
540 unsigned s_shift
, s_mask
;
542 if (get_z_shift_and_mask(format_desc
, &z_shift
, &z_mask
)) {
544 LLVMValueRef shift
= lp_build_const_int_vec(type
, z_shift
);
545 z_src
= LLVMBuildLShr(builder
, z_src
, shift
, "");
548 if (z_mask
!= 0xffffffff) {
549 LLVMValueRef mask
= lp_build_const_int_vec(type
, z_mask
);
550 z_src
= LLVMBuildAnd(builder
, z_src
, mask
, "");
551 z_dst
= LLVMBuildAnd(builder
, zs_dst
, mask
, "");
552 z_bitmask
= mask
; /* used below */
558 lp_build_name(z_dst
, "zsbuf.z");
561 if (get_s_shift_and_mask(format_desc
, &s_shift
, &s_mask
)) {
563 LLVMValueRef shift
= lp_build_const_int_vec(type
, s_shift
);
564 stencil_vals
= LLVMBuildLShr(builder
, zs_dst
, shift
, "");
565 stencil_shift
= shift
; /* used below */
568 stencil_vals
= zs_dst
;
571 if (s_mask
!= 0xffffffff) {
572 LLVMValueRef mask
= lp_build_const_int_vec(type
, s_mask
);
573 stencil_vals
= LLVMBuildAnd(builder
, stencil_vals
, mask
, "");
576 lp_build_name(stencil_vals
, "stencil");
581 if (stencil
[0].enabled
) {
582 /* convert scalar stencil refs into vectors */
583 stencil_refs
[0] = lp_build_broadcast_scalar(&bld
, stencil_refs
[0]);
584 stencil_refs
[1] = lp_build_broadcast_scalar(&bld
, stencil_refs
[1]);
586 s_pass_mask
= lp_build_stencil_test(&sbld
, stencil
,
587 stencil_refs
, stencil_vals
, face
);
589 /* apply stencil-fail operator */
591 LLVMValueRef s_fail_mask
= lp_build_andc(&bld
, orig_mask
, s_pass_mask
);
592 stencil_vals
= lp_build_stencil_op(&sbld
, stencil
, S_FAIL_OP
,
593 stencil_refs
, stencil_vals
,
598 if (depth
->enabled
) {
599 /* compare src Z to dst Z, returning 'pass' mask */
600 z_pass
= lp_build_cmp(&bld
, depth
->func
, z_src
, z_dst
);
602 if (!stencil
[0].enabled
) {
603 /* We can potentially skip all remaining operations here, but only
604 * if stencil is disabled because we still need to update the stencil
605 * buffer values. Don't need to update Z buffer values.
607 lp_build_mask_update(mask
, z_pass
);
610 if (depth
->writemask
) {
612 z_bitmask
= LLVMBuildAnd(builder
, mask
->value
, z_bitmask
, "");
614 z_bitmask
= mask
->value
;
616 z_dst
= lp_build_select(&bld
, z_bitmask
, z_src
, z_dst
);
619 if (stencil
[0].enabled
) {
620 /* update stencil buffer values according to z pass/fail result */
621 LLVMValueRef z_fail_mask
, z_pass_mask
;
623 /* apply Z-fail operator */
624 z_fail_mask
= lp_build_andc(&bld
, orig_mask
, z_pass
);
625 stencil_vals
= lp_build_stencil_op(&sbld
, stencil
, Z_FAIL_OP
,
626 stencil_refs
, stencil_vals
,
629 /* apply Z-pass operator */
630 z_pass_mask
= LLVMBuildAnd(bld
.builder
, orig_mask
, z_pass
, "");
631 stencil_vals
= lp_build_stencil_op(&sbld
, stencil
, Z_PASS_OP
,
632 stencil_refs
, stencil_vals
,
637 /* No depth test: apply Z-pass operator to stencil buffer values which
638 * passed the stencil test.
640 s_pass_mask
= LLVMBuildAnd(bld
.builder
, orig_mask
, s_pass_mask
, "");
641 stencil_vals
= lp_build_stencil_op(&sbld
, stencil
, Z_PASS_OP
,
642 stencil_refs
, stencil_vals
,
646 /* The Z bits are already in the right place but we may need to shift the
647 * stencil bits before ORing Z with Stencil to make the final pixel value.
649 if (stencil_vals
&& stencil_shift
)
650 stencil_vals
= LLVMBuildShl(bld
.builder
, stencil_vals
,
653 /* Finally, merge/store the z/stencil values */
654 if ((depth
->enabled
&& depth
->writemask
) ||
655 (stencil
[0].enabled
&& stencil
[0].writemask
)) {
657 if (z_dst
&& stencil_vals
)
658 zs_dst
= LLVMBuildOr(bld
.builder
, z_dst
, stencil_vals
, "");
662 zs_dst
= stencil_vals
;
664 LLVMBuildStore(builder
, zs_dst
, zs_dst_ptr
);
668 lp_build_mask_update(mask
, s_pass_mask
);
670 if (depth
->enabled
&& stencil
[0].enabled
)
671 lp_build_mask_update(mask
, z_pass
);