src/mesa/drivers/dri/i965/brw_multisample_state.h

   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 #ifndef BRW_MULTISAMPLE_STATE_H
  25 #define BRW_MULTISAMPLE_STATE_H
  26
  27 #include <stdint.h>
  28
  29 /**
  30  * Note: There are no standard multisample positions defined in OpenGL
  31  * specifications. Implementations have the freedom to pick the positions
  32  * which give plausible results. But the Vulkan specification does define
  33  * standard sample positions. So, we decided to pick the same pattern in
  34  * OpenGL as in Vulkan to keep it uniform across drivers and also to avoid
  35  * breaking applications which rely on this standard pattern.
  36  */
  37
  38 /**
  39  * 1x MSAA has a single sample at the center: (0.5, 0.5) -> (0x8, 0x8).
  40  *
  41  * 2x MSAA sample positions are (0.75, 0.75) and (0.25, 0.25):
  42  *   4 c
  43  * 4 1
  44  * c   0
  45  */
  46 static const uint32_t
  47 brw_multisample_positions_1x_2x = 0x008844cc;
  48
  49 /**
  50  * Sample positions:
  51  *   2 6 a e
  52  * 2   0
  53  * 6       1
  54  * a 2
  55  * e     3
  56  */
  57 static const uint32_t
  58 brw_multisample_positions_4x = 0xae2ae662;
  59
  60 /**
  61  * Sample positions:
  62  *
  63  * From the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE:
  64  * Programming Notes):
  65  *     "When programming the sample offsets (for NUMSAMPLES_4 or _8 and
  66  *     MSRASTMODE_xxx_PATTERN), the order of the samples 0 to 3 (or 7
  67  *     for 8X) must have monotonically increasing distance from the
  68  *     pixel center. This is required to get the correct centroid
  69  *     computation in the device."
  70  *
  71  * Sample positions:
  72  *   1 3 5 7 9 b d f
  73  * 1               7
  74  * 3     3
  75  * 5         0
  76  * 7 5
  77  * 9             2
  78  * b       1
  79  * d   4
  80  * f           6
  81  */
  82 static const uint32_t
  83 brw_multisample_positions_8x[] = { 0x53d97b95, 0xf1bf173d };
  84
  85 /**
  86  * Sample positions:
  87  *
  88  *    0 1 2 3 4 5 6 7 8 9 a b c d e f
  89  * 0   15
  90  * 1                  9
  91  * 2         10
  92  * 3                        7
  93  * 4                               13
  94  * 5                1
  95  * 6        4
  96  * 7                          3
  97  * 8 12
  98  * 9                    0
  99  * a            2
 100  * b                            6
 101  * c     11
 102  * d                      5
 103  * e              8
 104  * f                             14
 105  */
 106 static const uint32_t
 107 brw_multisample_positions_16x[] = {
 108    0xc75a7599, 0xb3dbad36, 0x2c42816e, 0x10eff408
 109 };
 110
 111 #endif /* BRW_MULTISAMPLE_STATE_H */