1 /* 2 * Copyright © 2013 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 <stdint.h> 25 26 /** 27 * Note: There are no standard multisample positions defined in OpenGL 28 * specifications. Implementations have the freedom to pick the positions 29 * which give plausible results. But the Vulkan specification does define 30 * standard sample positions. So, we decided to pick the same pattern in 31 * OpenGL as in Vulkan to keep it uniform across drivers and also to avoid 32 * breaking applications which rely on this standard pattern. 33 */ 34 35 /** 36 * 1x MSAA has a single sample at the center: (0.5, 0.5) -> (0x8, 0x8). 37 * 38 * 2x MSAA sample positions are (0.25, 0.25) and (0.75, 0.75): 39 * 4 c 40 * 4 0 41 * c 1 42 */ 43 static const uint32_t 44 brw_multisample_positions_1x_2x = 0x0088cc44; 45 46 /** 47 * Sample positions: 48 * 2 6 a e 49 * 2 0 50 * 6 1 51 * a 2 52 * e 3 53 */ 54 static const uint32_t 55 brw_multisample_positions_4x = 0xae2ae662; 56 57 /** 58 * Sample positions: 59 * 60 * From the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE: 61 * Programming Notes): 62 * "When programming the sample offsets (for NUMSAMPLES_4 or _8 and 63 * MSRASTMODE_xxx_PATTERN), the order of the samples 0 to 3 (or 7 64 * for 8X) must have monotonically increasing distance from the 65 * pixel center. This is required to get the correct centroid 66 * computation in the device." 67 * 68 * Sample positions: 69 * 1 3 5 7 9 b d f 70 * 1 7 71 * 3 3 72 * 5 0 73 * 7 5 74 * 9 2 75 * b 1 76 * d 4 77 * f 6 78 */ 79 static const uint32_t 80 brw_multisample_positions_8x[] = { 0x53d97b95, 0xf1bf173d }; 81 82 /** 83 * Sample positions: 84 * 85 * 0 1 2 3 4 5 6 7 8 9 a b c d e f 86 * 0 15 87 * 1 9 88 * 2 10 89 * 3 7 90 * 4 13 91 * 5 1 92 * 6 4 93 * 7 3 94 * 8 12 95 * 9 0 96 * a 2 97 * b 6 98 * c 11 99 * d 5 100 * e 8 101 * f 14 102 */ 103 static const uint32_t 104 brw_multisample_positions_16x[] = { 105 0xc75a7599, 0xb3dbad36, 0x2c42816e, 0x10eff408 106 }; 107