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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"
/* Sample positions:
* 2 6 a e
* 2 0
* 6 1
* a 2
* e 3
*/
static uint32_t
sample_positions_4x[] = { 0xae2ae662 };
/* Sample positions are based on a solution to the "8 queens" puzzle.
* Rationale: in a solution to the 8 queens puzzle, no two queens share
* a row, column, or diagonal. This is a desirable property for samples
* in a multisampling pattern, because it ensures that the samples are
* relatively uniformly distributed through the pixel.
*
* There are several solutions to the 8 queens puzzle (see
* http://en.wikipedia.org/wiki/Eight_queens_puzzle). This solution was
* chosen because it has a queen close to the center; this should
* improve the accuracy of centroid interpolation, since the hardware
* implements centroid interpolation by choosing the centermost sample
* that overlaps with the primitive being drawn.
*
* Note: from the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE:
* Programming Notes):
*
* "When programming the sample offsets (for NUMSAMPLES_4 or _8 and
* MSRASTMODE_xxx_PATTERN), the order of the samples 0 to 3 (or 7
* for 8X) must have monotonically increasing distance from the
* pixel center. This is required to get the correct centroid
* computation in the device."
*
* Sample positions:
* 1 3 5 7 9 b d f
* 1 5
* 3 2
* 5 6
* 7 4
* 9 0
* b 3
* d 1
* f 7
*/
static uint32_t
sample_positions_8x[] = { 0xdbb39d79, 0x3ff55117 };
void
gen6_get_sample_position(struct gl_context *ctx,
struct gl_framebuffer *fb,
GLuint index, GLfloat *result)
{
switch (fb->Visual.samples) {
case 1:
result[0] = result[1] = 0.5f;
break;
case 4: {
uint8_t val = (uint8_t)(sample_positions_4x[0] >> (8*index));
result[0] = ((val >> 4) & 0xf) / 16.0f;
result[1] = (val & 0xf) / 16.0f;
break;
}
case 8: {
uint8_t val = (uint8_t)(sample_positions_8x[index>>2] >> (8*(index & 3)));
result[0] = ((val >> 4) & 0xf) / 16.0f;
result[1] = (val & 0xf) / 16.0f;
break;
}
default:
assert(!"Not implemented");
}
}
/**
* 3DSTATE_MULTISAMPLE
*/
void
gen6_emit_3dstate_multisample(struct brw_context *brw,
unsigned num_samples)
{
struct intel_context *intel = &brw->intel;
uint32_t number_of_multisamples = 0;
uint32_t sample_positions_3210 = 0;
uint32_t sample_positions_7654 = 0;
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 = sample_positions_4x[0];
break;
case 8:
number_of_multisamples = MS_NUMSAMPLES_8;
sample_positions_3210 = sample_positions_8x[0];
sample_positions_7654 = sample_positions_8x[1];
break;
default:
assert(!"Unrecognized num_samples in gen6_emit_3dstate_multisample");
break;
}
int len = intel->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 (intel->gen >= 7)
OUT_BATCH(sample_positions_7654);
ADVANCE_BATCH();
}
/**
* 3DSTATE_SAMPLE_MASK
*/
void
gen6_emit_3dstate_sample_mask(struct brw_context *brw,
unsigned num_samples, float coverage,
bool coverage_invert, unsigned sample_mask)
{
struct intel_context *intel = &brw->intel;
BEGIN_BATCH(2);
OUT_BATCH(_3DSTATE_SAMPLE_MASK << 16 | (2 - 2));
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;
OUT_BATCH(coverage_bits & sample_mask);
} else {
OUT_BATCH(1);
}
ADVANCE_BATCH();
}
static void upload_multisample_state(struct brw_context *brw)
{
struct intel_context *intel = &brw->intel;
struct gl_context *ctx = &intel->ctx;
float coverage = 1.0;
float coverage_invert = false;
unsigned sample_mask = ~0u;
/* _NEW_BUFFERS */
unsigned num_samples = ctx->DrawBuffer->Visual.samples;
/* _NEW_MULTISAMPLE */
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;
}
}
/* 3DSTATE_MULTISAMPLE is nonpipelined. */
intel_emit_post_sync_nonzero_flush(intel);
gen6_emit_3dstate_multisample(brw, num_samples);
gen6_emit_3dstate_sample_mask(brw, num_samples, coverage,
coverage_invert, sample_mask);
}
const struct brw_tracked_state gen6_multisample_state = {
.dirty = {
.mesa = _NEW_BUFFERS |
_NEW_MULTISAMPLE,
.brw = BRW_NEW_CONTEXT,
.cache = 0
},
.emit = upload_multisample_state
};
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