aboutsummaryrefslogtreecommitdiffstats
path: root/src/gallium/drivers/llvmpipe/lp_bld_depth.c
blob: 2cd6e6b92175cf82b76d10199068637e0c15176b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
/**************************************************************************
 *
 * Copyright 2009 VMware, Inc.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

/**
 * @file
 * Depth/stencil testing to LLVM IR translation.
 *
 * To be done accurately/efficiently the depth/stencil test must be done with
 * the same type/format of the depth/stencil buffer, which implies massaging
 * the incoming depths to fit into place. Using a more straightforward
 * type/format for depth/stencil values internally and only convert when
 * flushing would avoid this, but it would most likely result in depth fighting
 * artifacts.
 *
 * We are free to use a different pixel layout though. Since our basic
 * processing unit is a quad (2x2 pixel block) we store the depth/stencil
 * values tiled, a quad at time. That is, a depth buffer containing 
 *
 *  Z11 Z12 Z13 Z14 ...
 *  Z21 Z22 Z23 Z24 ...
 *  Z31 Z32 Z33 Z34 ...
 *  Z41 Z42 Z43 Z44 ...
 *  ... ... ... ... ...
 *
 * will actually be stored in memory as
 *
 *  Z11 Z12 Z21 Z22 Z13 Z14 Z23 Z24 ...
 *  Z31 Z32 Z41 Z42 Z33 Z34 Z43 Z44 ...
 *  ... ... ... ... ... ... ... ... ...
 *
 * FIXME: Code generate stencil test
 *
 * @author Jose Fonseca <jfonseca@vmware.com>
 */

#include "pipe/p_state.h"
#include "util/u_format.h"

#include "lp_bld_type.h"
#include "lp_bld_const.h"
#include "lp_bld_logic.h"
#include "lp_bld_flow.h"
#include "lp_bld_debug.h"
#include "lp_bld_depth.h"


/**
 * Return a type appropriate for depth/stencil testing.
 */
union lp_type
lp_depth_type(const struct util_format_description *format_desc,
              unsigned length)
{
   union lp_type type;
   unsigned swizzle;

   assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
   assert(format_desc->block.width == 1);
   assert(format_desc->block.height == 1);

   swizzle = format_desc->swizzle[0];
   assert(swizzle < 4);

   type.value = 0;
   type.width = format_desc->block.bits;

   if(format_desc->channel[swizzle].type == UTIL_FORMAT_TYPE_FLOAT) {
      type.floating = TRUE;
      assert(swizzle = 0);
      assert(format_desc->channel[swizzle].size == format_desc->block.bits);
   }
   else if(format_desc->channel[swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED) {
      assert(format_desc->block.bits <= 32);
      if(format_desc->channel[swizzle].normalized)
         type.norm = TRUE;
   }
   else
      assert(0);

   assert(type.width <= length);
   type.length = length / type.width;

   return type;
}


/**
 * Depth test.
 */
void
lp_build_depth_test(LLVMBuilderRef builder,
                    const struct pipe_depth_state *state,
                    union lp_type type,
                    const struct util_format_description *format_desc,
                    struct lp_build_mask_context *mask,
                    LLVMValueRef src,
                    LLVMValueRef dst_ptr)
{
   struct lp_build_context bld;
   unsigned z_swizzle;
   LLVMValueRef dst;
   LLVMValueRef z_bitmask = NULL;
   LLVMValueRef test;

   if(!state->enabled)
      return;

   assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS);
   assert(format_desc->block.width == 1);
   assert(format_desc->block.height == 1);

   z_swizzle = format_desc->swizzle[0];
   if(z_swizzle == UTIL_FORMAT_SWIZZLE_NONE)
      return;

   /* Sanity checking */
   assert(z_swizzle < 4);
   assert(format_desc->block.bits == type.width);
   if(type.floating) {
      assert(z_swizzle == 0);
      assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_FLOAT);
      assert(format_desc->channel[z_swizzle].size == format_desc->block.bits);
   }
   else {
      assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED);
      assert(format_desc->channel[z_swizzle].normalized);
      assert(!type.fixed);
      assert(!type.sign);
      assert(type.norm);
   }

   /* Setup build context */
   lp_build_context_init(&bld, builder, type);

   dst = LLVMBuildLoad(builder, dst_ptr, "");

   lp_build_name(dst, "zsbuf");

   /* Align the source depth bits with the destination's, and mask out any
    * stencil or padding bits from both */
   if(format_desc->channel[z_swizzle].size == format_desc->block.bits) {
      assert(z_swizzle == 0);
      /* nothing to do */
   }
   else {
      unsigned padding_left;
      unsigned padding_right;
      unsigned chan;

      assert(format_desc->layout == UTIL_FORMAT_LAYOUT_ARITH);
      assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED);
      assert(format_desc->channel[z_swizzle].size <= format_desc->block.bits);
      assert(format_desc->channel[z_swizzle].normalized);

      padding_right = 0;
      for(chan = 0; chan < z_swizzle; ++chan)
         padding_right += format_desc->channel[chan].size;
      padding_left = format_desc->block.bits - format_desc->channel[z_swizzle].size;

      if(padding_left || padding_right) {
         const long long mask_left = ((long long)1 << (format_desc->block.bits - padding_left)) - 1;
         const long long mask_right = ((long long)1 << (padding_right)) - 1;
         z_bitmask = lp_build_int_const_scalar(type, mask_left & mask_right);
      }

      if(padding_left)
         src = LLVMBuildLShr(builder, src, lp_build_int_const_scalar(type, padding_left), "");
      if(padding_right)
         src = LLVMBuildAnd(builder, src, z_bitmask, "");
      if(padding_left || padding_right)
         dst = LLVMBuildAnd(builder, dst, z_bitmask, "");
   }

   lp_build_name(dst, "zsbuf.z");

   test = lp_build_cmp(&bld, state->func, src, dst);
   lp_build_mask_update(mask, test);

   if(state->writemask) {
      if(z_bitmask)
         z_bitmask = LLVMBuildAnd(builder, mask->value, z_bitmask, "");
      else
         z_bitmask = mask->value;

      dst = lp_build_select(&bld, z_bitmask, src, dst);
      LLVMBuildStore(builder, dst, dst_ptr);
   }

   assert(!state->occlusion_count);
}