1 /*
2 * Copyright © 2012 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
24 #include "intel_batchbuffer.h"
25
26 #include "brw_context.h"
27 #include "brw_defines.h"
28 #include "brw_multisample_state.h"
29 #include "main/framebuffer.h"
30
31 void
gen6_get_sample_position(struct gl_context * ctx,struct gl_framebuffer * fb,GLuint index,GLfloat * result)32 gen6_get_sample_position(struct gl_context *ctx,
33 struct gl_framebuffer *fb,
34 GLuint index, GLfloat *result)
35 {
36 uint8_t bits;
37
38 switch (_mesa_geometric_samples(fb)) {
39 case 1:
40 result[0] = result[1] = 0.5f;
41 return;
42 case 2:
43 bits = brw_multisample_positions_1x_2x >> (8 * index);
44 break;
45 case 4:
46 bits = brw_multisample_positions_4x >> (8 * index);
47 break;
48 case 8:
49 bits = brw_multisample_positions_8x[index >> 2] >> (8 * (index & 3));
50 break;
51 case 16:
52 bits = brw_multisample_positions_16x[index >> 2] >> (8 * (index & 3));
53 break;
54 default:
55 unreachable("Not implemented");
56 }
57
58 /* Convert from U0.4 back to a floating point coordinate. */
59 result[0] = ((bits >> 4) & 0xf) / 16.0f;
60 result[1] = (bits & 0xf) / 16.0f;
61 }
62
63 /**
64 * Sample index layout shows the numbering of slots in a rectangular
65 * grid of samples with in a pixel. Sample number layout shows the
66 * rectangular grid of samples roughly corresponding to the real sample
67 * locations with in a pixel. Sample number layout matches the sample
68 * index layout in case of 2X and 4x MSAA, but they are different in
69 * case of 8X MSAA.
70 *
71 * 2X MSAA sample index / number layout
72 * ---------
73 * | 0 | 1 |
74 * ---------
75 *
76 * 4X MSAA sample index / number layout
77 * ---------
78 * | 0 | 1 |
79 * ---------
80 * | 2 | 3 |
81 * ---------
82 *
83 * 8X MSAA sample index layout 8x MSAA sample number layout
84 * --------- ---------
85 * | 0 | 1 | | 5 | 2 |
86 * --------- ---------
87 * | 2 | 3 | | 4 | 6 |
88 * --------- ---------
89 * | 4 | 5 | | 0 | 3 |
90 * --------- ---------
91 * | 6 | 7 | | 7 | 1 |
92 * --------- ---------
93 *
94 * 16X MSAA sample index layout 16x MSAA sample number layout
95 * ----------------- -----------------
96 * | 0 | 1 | 2 | 3 | |15 |10 | 9 | 7 |
97 * ----------------- -----------------
98 * | 4 | 5 | 6 | 7 | | 4 | 1 | 3 |13 |
99 * ----------------- -----------------
100 * | 8 | 9 |10 |11 | |12 | 2 | 0 | 6 |
101 * ----------------- -----------------
102 * |12 |13 |14 |15 | |11 | 8 | 5 |14 |
103 * ----------------- -----------------
104 *
105 * A sample map is used to map sample indices to sample numbers.
106 */
107 void
gen6_set_sample_maps(struct gl_context * ctx)108 gen6_set_sample_maps(struct gl_context *ctx)
109 {
110 uint8_t map_2x[2] = {0, 1};
111 uint8_t map_4x[4] = {0, 1, 2, 3};
112 uint8_t map_8x[8] = {3, 7, 5, 0, 1, 2, 4, 6};
113 uint8_t map_16x[16] = { 15, 10, 9, 7, 4, 1, 3, 13,
114 12, 2, 0, 6, 11, 8, 5, 14 };
115
116 memcpy(ctx->Const.SampleMap2x, map_2x, sizeof(map_2x));
117 memcpy(ctx->Const.SampleMap4x, map_4x, sizeof(map_4x));
118 memcpy(ctx->Const.SampleMap8x, map_8x, sizeof(map_8x));
119 memcpy(ctx->Const.SampleMap16x, map_16x, sizeof(map_16x));
120 }
121