1 /*
2 * Copyright © 2015 Intel Corporation
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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * 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 NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Jason Ekstrand <jason@jlekstrand.net>
25 */
26
27 #include "nir.h"
28 #include "nir_builder.h"
29
30 /**
31 * This file implements a NIR lowering pass to perform the normalization of
32 * the cubemap coordinates to have the largest magnitude component be -1.0
33 * or 1.0. This is based on the old GLSL IR based pass by Eric.
34 */
35
36 static bool
normalize_cubemap_coords_block(nir_block * block,nir_builder * b)37 normalize_cubemap_coords_block(nir_block *block, nir_builder *b)
38 {
39 bool progress = false;
40
41 nir_foreach_instr(instr, block) {
42 if (instr->type != nir_instr_type_tex)
43 continue;
44
45 nir_tex_instr *tex = nir_instr_as_tex(instr);
46 if (tex->sampler_dim != GLSL_SAMPLER_DIM_CUBE)
47 continue;
48
49 b->cursor = nir_before_instr(&tex->instr);
50
51 for (unsigned i = 0; i < tex->num_srcs; i++) {
52 if (tex->src[i].src_type != nir_tex_src_coord)
53 continue;
54
55 nir_ssa_def *orig_coord =
56 nir_ssa_for_src(b, tex->src[i].src, nir_tex_instr_src_size(tex, i));
57 assert(orig_coord->num_components >= 3);
58
59 nir_ssa_def *abs = nir_fabs(b, orig_coord);
60 nir_ssa_def *norm = nir_fmax(b, nir_channel(b, abs, 0),
61 nir_fmax(b, nir_channel(b, abs, 1),
62 nir_channel(b, abs, 2)));
63
64 nir_ssa_def *normalized = nir_fmul(b, orig_coord, nir_frcp(b, norm));
65
66 /* Array indices don't have to be normalized, so make a new vector
67 * with the coordinate's array index untouched.
68 */
69 if (tex->coord_components == 4) {
70 normalized = nir_vec4(b,
71 nir_channel(b, normalized, 0),
72 nir_channel(b, normalized, 1),
73 nir_channel(b, normalized, 2),
74 nir_channel(b, orig_coord, 3));
75 }
76
77 nir_instr_rewrite_src(&tex->instr,
78 &tex->src[i].src,
79 nir_src_for_ssa(normalized));
80
81 progress = true;
82 }
83 }
84
85 return progress;
86 }
87
88 static bool
normalize_cubemap_coords_impl(nir_function_impl * impl)89 normalize_cubemap_coords_impl(nir_function_impl *impl)
90 {
91 nir_builder b;
92 nir_builder_init(&b, impl);
93 bool progress = false;
94
95 nir_foreach_block(block, impl) {
96 progress |= normalize_cubemap_coords_block(block, &b);
97 }
98
99 nir_metadata_preserve(impl, nir_metadata_block_index |
100 nir_metadata_dominance);
101
102 return progress;
103 }
104
105 bool
nir_normalize_cubemap_coords(nir_shader * shader)106 nir_normalize_cubemap_coords(nir_shader *shader)
107 {
108 bool progress = false;
109
110 nir_foreach_function(function, shader) {
111 if (function->impl)
112 progress = normalize_cubemap_coords_impl(function->impl) || progress;
113 }
114
115 return progress;
116 }
117