#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
{
struct intel_context *intel = &brw->intel;
- /* TODO: 8x MSAA not implemented */
- assert(num_samples <= 4);
+ 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 |
- (num_samples > 0 ? MS_NUMSAMPLES_4 : MS_NUMSAMPLES_1));
- OUT_BATCH(num_samples > 0 ? 0xae2ae662 : 0); /* positions for 4/8-sample */
+ OUT_BATCH(MS_PIXEL_LOCATION_CENTER | number_of_multisamples);
+ OUT_BATCH(sample_positions_3210);
if (intel->gen >= 7)
- OUT_BATCH(0);
+ OUT_BATCH(sample_positions_7654);
ADVANCE_BATCH();
}
void
gen6_emit_3dstate_sample_mask(struct brw_context *brw,
unsigned num_samples, float coverage,
- bool coverage_invert)
+ bool coverage_invert, unsigned sample_mask)
{
struct intel_context *intel = &brw->intel;
- /* TODO: 8x MSAA not implemented */
- assert(num_samples <= 4);
-
BEGIN_BATCH(2);
OUT_BATCH(_3DSTATE_SAMPLE_MASK << 16 | (2 - 2));
- if (num_samples > 0) {
+ 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);
+ OUT_BATCH(coverage_bits & sample_mask);
} else {
OUT_BATCH(1);
}
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 && ctx->Multisample.SampleCoverage) {
- coverage = ctx->Multisample.SampleCoverageValue;
- coverage_invert = ctx->Multisample.SampleCoverageInvert;
+ 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);
+ gen6_emit_3dstate_sample_mask(brw, num_samples, coverage,
+ coverage_invert, sample_mask);
}
projects / mesa.git / blobdiff