1 /*
2 * Copyright 2018-2019 Collabora Ltd.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * on the rights to use, copy, modify, merge, publish, distribute, sub
8 * license, and/or sell copies of the Software, and to permit persons to whom
9 * the Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
21 * USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #include "nir_builder.h"
25
26 static void
lower_pos_write(nir_builder * b,struct nir_instr * instr)27 lower_pos_write(nir_builder *b, struct nir_instr *instr)
28 {
29 if (instr->type != nir_instr_type_intrinsic)
30 return;
31
32 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
33 if (intr->intrinsic != nir_intrinsic_store_deref)
34 return;
35
36 nir_variable *var = nir_intrinsic_get_var(intr, 0);
37 if (var->data.mode != nir_var_shader_out ||
38 var->data.location != VARYING_SLOT_POS)
39 return;
40
41 b->cursor = nir_before_instr(&intr->instr);
42
43 nir_ssa_def *pos = nir_ssa_for_src(b, intr->src[1], 4);
44 nir_ssa_def *def = nir_vec4(b,
45 nir_channel(b, pos, 0),
46 nir_channel(b, pos, 1),
47 nir_fmul_imm(b,
48 nir_fadd(b,
49 nir_channel(b, pos, 2),
50 nir_channel(b, pos, 3)),
51 0.5),
52 nir_channel(b, pos, 3));
53 nir_instr_rewrite_src(&intr->instr, intr->src + 1, nir_src_for_ssa(def));
54 }
55
56 void
nir_lower_clip_halfz(nir_shader * shader)57 nir_lower_clip_halfz(nir_shader *shader)
58 {
59 if (shader->info.stage != MESA_SHADER_VERTEX &&
60 shader->info.stage != MESA_SHADER_GEOMETRY &&
61 shader->info.stage != MESA_SHADER_TESS_EVAL)
62 return;
63
64 nir_foreach_function(function, shader) {
65 if (function->impl) {
66 nir_builder b;
67 nir_builder_init(&b, function->impl);
68
69 nir_foreach_block(block, function->impl) {
70 nir_foreach_instr_safe(instr, block) {
71 lower_pos_write(&b, instr);
72 }
73 }
74
75 nir_metadata_preserve(function->impl, nir_metadata_block_index |
76 nir_metadata_dominance);
77 }
78 }
79 }
80