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/*

 * Copyright © 2012 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "intel_batchbuffer.h"

#include "brw_context.h"

#include "brw_defines.h"

#include "brw_multisample_state.h"

void

gen6_get_sample_position(struct gl_context *ctx,

                         struct gl_framebuffer *fb,

                         GLuint index, GLfloat *result)

{

   uint8_t bits;

   switch (fb->Visual.samples) {

   case 1:

      result[0] = result[1] = 0.5f;

      return;

   case 2:

      bits = brw_multisample_positions_1x_2x >> (8 * index);

      break;

   case 4:

      bits = brw_multisample_positions_4x >> (8 * index);

      break;

   case 8:

      bits = brw_multisample_positions_8x[index >> 2] >> (8 * (index & 3));

      break;

   default:

      unreachable("Not implemented");

   }

   /* Convert from U0.4 back to a floating point coordinate. */

   result[0] = ((bits >> 4) & 0xf) / 16.0f;

   result[1] = (bits & 0xf) / 16.0f;

}

/**

 * Sample index layout shows the numbering of slots in a rectangular

 * grid of samples with in a pixel. Sample number layout shows the

 * rectangular grid of samples roughly corresponding to the real sample

 * locations with in a pixel. Sample number layout matches the sample

 * index layout in case of 2X and 4x MSAA, but they are different in

 * case of 8X MSAA.

 *

 * 2X MSAA sample index / number layout

 *           ---------

 *           | 0 | 1 |

 *           ---------

 *

 * 4X MSAA sample index / number layout

 *           ---------

 *           | 0 | 1 |

 *           ---------

 *           | 2 | 3 |

 *           ---------

 *

 * 8X MSAA sample index layout    8x MSAA sample number layout

 *           ---------                      ---------

 *           | 0 | 1 |                      | 5 | 2 |

 *           ---------                      ---------

 *           | 2 | 3 |                      | 4 | 6 |

 *           ---------                      ---------

 *           | 4 | 5 |                      | 0 | 3 |

 *           ---------                      ---------

 *           | 6 | 7 |                      | 7 | 1 |

 *           ---------                      ---------

 *

 * A sample map is used to map sample indices to sample numbers.

 */

void

gen6_set_sample_maps(struct gl_context *ctx)

{

   uint8_t map_2x[2] = {0, 1};

   uint8_t map_4x[4] = {0, 1, 2, 3};

   uint8_t map_8x[8] = {5, 2, 4, 6, 0, 3, 7, 1};

   memcpy(ctx->Const.SampleMap2x, map_2x, sizeof(map_2x));

   memcpy(ctx->Const.SampleMap4x, map_4x, sizeof(map_4x));

   memcpy(ctx->Const.SampleMap8x, map_8x, sizeof(map_8x));

}

/**

 * 3DSTATE_MULTISAMPLE

 */

void

gen6_emit_3dstate_multisample(struct brw_context *brw,

                              unsigned num_samples)

{

   uint32_t number_of_multisamples = 0;

   uint32_t sample_positions_3210 = 0;

   uint32_t sample_positions_7654 = 0;

   assert(brw->gen < 8);

   switch (num_samples) {

   case 0:

   case 1:

      number_of_multisamples = MS_NUMSAMPLES_1;

      break;

   case 4:

      number_of_multisamples = MS_NUMSAMPLES_4;

      sample_positions_3210 = brw_multisample_positions_4x;

      break;

   case 8:

      number_of_multisamples = MS_NUMSAMPLES_8;

      sample_positions_3210 = brw_multisample_positions_8x[0];

      sample_positions_7654 = brw_multisample_positions_8x[1];

      break;

   default:

      unreachable("Unrecognized num_samples in gen6_emit_3dstate_multisample");

   }

   int len = brw->gen >= 7 ? 4 : 3;

   BEGIN_BATCH(len);

   OUT_BATCH(_3DSTATE_MULTISAMPLE << 16 | (len - 2));

   OUT_BATCH(MS_PIXEL_LOCATION_CENTER | number_of_multisamples);

   OUT_BATCH(sample_positions_3210);

   if (brw->gen >= 7)

      OUT_BATCH(sample_positions_7654);

   ADVANCE_BATCH();

}

unsigned

gen6_determine_sample_mask(struct brw_context *brw)

{

   struct gl_context *ctx = &brw->ctx;

   float coverage = 1.0;

   float coverage_invert = false;

   unsigned sample_mask = ~0u;

   /* BRW_NEW_NUM_SAMPLES */

   unsigned num_samples = brw->num_samples;

   if (ctx->Multisample._Enabled) {

      if (ctx->Multisample.SampleCoverage) {

         coverage = ctx->Multisample.SampleCoverageValue;

         coverage_invert = ctx->Multisample.SampleCoverageInvert;

      }

      if (ctx->Multisample.SampleMask) {

         sample_mask = ctx->Multisample.SampleMaskValue;

      }

   }

   if (num_samples > 1) {

      int coverage_int = (int) (num_samples * coverage + 0.5);

      uint32_t coverage_bits = (1 << coverage_int) - 1;

      if (coverage_invert)

         coverage_bits ^= (1 << num_samples) - 1;

      return coverage_bits & sample_mask;

   } else {

      return 1;

   }

}

/**

 * 3DSTATE_SAMPLE_MASK

 */

void

gen6_emit_3dstate_sample_mask(struct brw_context *brw, unsigned mask)

{

   BEGIN_BATCH(2);

   OUT_BATCH(_3DSTATE_SAMPLE_MASK << 16 | (2 - 2));

   OUT_BATCH(mask);

   ADVANCE_BATCH();

}

static void upload_multisample_state(struct brw_context *brw)

{

   /* BRW_NEW_NUM_SAMPLES */

   gen6_emit_3dstate_multisample(brw, brw->num_samples);

   gen6_emit_3dstate_sample_mask(brw, gen6_determine_sample_mask(brw));

}

const struct brw_tracked_state gen6_multisample_state = {

   .dirty = {

      .mesa = _NEW_MULTISAMPLE,

      .brw = BRW_NEW_CONTEXT |

             BRW_NEW_NUM_SAMPLES,

   },

   .emit = upload_multisample_state

};