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 29 30 /** 31 * 3DSTATE_MULTISAMPLE 32 */ 33 void 34 gen6_emit_3dstate_multisample(struct brw_context *brw, 35 unsigned num_samples) 36 { 37 struct intel_context *intel = &brw->intel; 38 39 uint32_t number_of_multisamples = 0; 40 uint32_t sample_positions_3210 = 0; 41 uint32_t sample_positions_7654 = 0; 42 43 switch (num_samples) { 44 case 0: 45 case 1: 46 number_of_multisamples = MS_NUMSAMPLES_1; 47 break; 48 case 4: 49 number_of_multisamples = MS_NUMSAMPLES_4; 50 /* Sample positions: 51 * 2 6 a e 52 * 2 0 53 * 6 1 54 * a 2 55 * e 3 56 */ 57 sample_positions_3210 = 0xae2ae662; 58 break; 59 case 8: 60 number_of_multisamples = MS_NUMSAMPLES_8; 61 /* Sample positions are based on a solution to the "8 queens" puzzle. 62 * Rationale: in a solution to the 8 queens puzzle, no two queens share 63 * a row, column, or diagonal. This is a desirable property for samples 64 * in a multisampling pattern, because it ensures that the samples are 65 * relatively uniformly distributed through the pixel. 66 * 67 * There are several solutions to the 8 queens puzzle (see 68 * http://en.wikipedia.org/wiki/Eight_queens_puzzle). This solution was 69 * chosen because it has a queen close to the center; this should 70 * improve the accuracy of centroid interpolation, since the hardware 71 * implements centroid interpolation by choosing the centermost sample 72 * that overlaps with the primitive being drawn. 73 * 74 * Note: from the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE: 75 * Programming Notes): 76 * 77 * "When programming the sample offsets (for NUMSAMPLES_4 or _8 and 78 * MSRASTMODE_xxx_PATTERN), the order of the samples 0 to 3 (or 7 79 * for 8X) must have monotonically increasing distance from the 80 * pixel center. This is required to get the correct centroid 81 * computation in the device." 82 * 83 * Sample positions: 84 * 1 3 5 7 9 b d f 85 * 1 5 86 * 3 2 87 * 5 6 88 * 7 4 89 * 9 0 90 * b 3 91 * d 1 92 * f 7 93 */ 94 sample_positions_3210 = 0xdbb39d79; 95 sample_positions_7654 = 0x3ff55117; 96 break; 97 default: 98 assert(!"Unrecognized num_samples in gen6_emit_3dstate_multisample"); 99 break; 100 } 101 102 int len = intel->gen >= 7 ? 4 : 3; 103 BEGIN_BATCH(len); 104 OUT_BATCH(_3DSTATE_MULTISAMPLE << 16 | (len - 2)); 105 OUT_BATCH(MS_PIXEL_LOCATION_CENTER | number_of_multisamples); 106 OUT_BATCH(sample_positions_3210); 107 if (intel->gen >= 7) 108 OUT_BATCH(sample_positions_7654); 109 ADVANCE_BATCH(); 110 } 111 112 113 /** 114 * 3DSTATE_SAMPLE_MASK 115 */ 116 void 117 gen6_emit_3dstate_sample_mask(struct brw_context *brw, 118 unsigned num_samples, float coverage, 119 bool coverage_invert) 120 { 121 struct intel_context *intel = &brw->intel; 122 123 BEGIN_BATCH(2); 124 OUT_BATCH(_3DSTATE_SAMPLE_MASK << 16 | (2 - 2)); 125 if (num_samples > 1) { 126 int coverage_int = (int) (num_samples * coverage + 0.5); 127 uint32_t coverage_bits = (1 << coverage_int) - 1; 128 if (coverage_invert) 129 coverage_bits ^= (1 << num_samples) - 1; 130 OUT_BATCH(coverage_bits); 131 } else { 132 OUT_BATCH(1); 133 } 134 ADVANCE_BATCH(); 135 } 136 137 138 static void upload_multisample_state(struct brw_context *brw) 139 { 140 struct intel_context *intel = &brw->intel; 141 struct gl_context *ctx = &intel->ctx; 142 float coverage = 1.0; 143 float coverage_invert = false; 144 145 /* _NEW_BUFFERS */ 146 unsigned num_samples = ctx->DrawBuffer->Visual.samples; 147 148 /* _NEW_MULTISAMPLE */ 149 if (ctx->Multisample._Enabled && ctx->Multisample.SampleCoverage) { 150 coverage = ctx->Multisample.SampleCoverageValue; 151 coverage_invert = ctx->Multisample.SampleCoverageInvert; 152 } 153 154 /* 3DSTATE_MULTISAMPLE is nonpipelined. */ 155 intel_emit_post_sync_nonzero_flush(intel); 156 157 gen6_emit_3dstate_multisample(brw, num_samples); 158 gen6_emit_3dstate_sample_mask(brw, num_samples, coverage, coverage_invert); 159 } 160 161 162 const struct brw_tracked_state gen6_multisample_state = { 163 .dirty = { 164 .mesa = _NEW_BUFFERS | 165 _NEW_MULTISAMPLE, 166 .brw = BRW_NEW_CONTEXT, 167 .cache = 0 168 }, 169 .emit = upload_multisample_state 170 }; 171
