[Mesa-dev] [PATCH 09/15] radeonsi: switch back to standard DX sample positions

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

Apps may rely on them.
---
 src/gallium/drivers/radeonsi/si_state_msaa.c | 43 ++++++++++++--------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_msaa.c b/src/gallium/drivers/radeonsi/si_state_msaa.c
index 10232a5e18b..f9387e75ed1 100644
--- a/src/gallium/drivers/radeonsi/si_state_msaa.c
+++ b/src/gallium/drivers/radeonsi/si_state_msaa.c
@@ -80,58 +80,67 @@
  * Groups of 8 samples in the same vicinity in 16x MSAA:
  *   Left half:  {0,2,4,6,8,10,12,14}
  *   Right half: {1,3,5,7,9,11,13,15}
  */
 
 /* 1x MSAA */
 static const uint32_t sample_locs_1x =
 	FILL_SREG( 0, 0,   0, 0,   0, 0,   0, 0); /* S1, S2, S3 fields are not used by 1x */
 static const uint64_t centroid_priority_1x = 0x0000000000000000ull;
 
-/* 2x MSAA */
+/* 2x MSAA (the positions are sorted for EQAA) */
 static const uint32_t sample_locs_2x =
 	FILL_SREG(-4,-4,   4, 4,   0, 0,   0, 0); /* S2 & S3 fields are not used by 2x MSAA */
 static const uint64_t centroid_priority_2x = 0x1010101010101010ull;
 
-/* 4x, 8x, and 16x MSAA
- * - The first 4 locations happen to be optimal for 4x MSAA, better than
- *   the standard DX 4x locations.
- * - The first 8 locations happen to be almost as good as 8x DX locations,
- *   but the DX locations are horrible for worst-case EQAA 8s4f and 8s2f.
- */
-static const uint32_t sample_locs_4x_8x_16x[] = {
+/* 4x MSAA (the positions are sorted for EQAA) */
+static const uint32_t sample_locs_4x =
+	FILL_SREG(-2,-6,   2, 6,   -6, 2,  6,-2);
+static const uint64_t centroid_priority_4x = 0x3210321032103210ull;
+
+/* 8x MSAA (the positions are sorted for EQAA) */
+static const uint32_t sample_locs_8x[] = {
+	FILL_SREG(-3,-5,   5, 1,  -1, 3,   7,-7),
+	FILL_SREG(-7,-1,   3, 7,  -5, 5,   1,-3),
+};
+static const uint64_t centroid_priority_8x = 0x3546012735460127ull;
+
+/* 16x MSAA (the positions are sorted for EQAA) */
+static const uint32_t sample_locs_16x[] = {
 	FILL_SREG(-5,-2,   5, 3,  -2, 6,   3,-5),
-	FILL_SREG(-6,-7,   1, 1,  -6, 4,   7,-3),
+	FILL_SREG(-4,-6,   1, 1,  -6, 4,   7,-4),
 	FILL_SREG(-1,-3,   6, 7,  -3, 2,   0,-7),
-	FILL_SREG(-4,-6,   2, 5,  -8, 0,   4,-1),
+	FILL_SREG(-7,-8,   2, 5,  -8, 0,   4,-1),
 };
-static const uint64_t centroid_priority_4x = 0x2310231023102310ull;
-static const uint64_t centroid_priority_8x = 0x4762310547623105ull;
-static const uint64_t centroid_priority_16x = 0x49e7c6b231d0fa85ull;
+static const uint64_t centroid_priority_16x = 0xc97e64b231d0fa85ull;
 
 static void si_get_sample_position(struct pipe_context *ctx, unsigned sample_count,
 				   unsigned sample_index, float *out_value)
 {
 	const uint32_t *sample_locs;
 
 	switch (sample_count) {
 	case 1:
 	default:
 		sample_locs = &sample_locs_1x;
 		break;
 	case 2:
 		sample_locs = &sample_locs_2x;
 		break;
 	case 4:
+		sample_locs = &sample_locs_4x;
+		break;
 	case 8:
+		sample_locs = sample_locs_8x;
+		break;
 	case 16:
-		sample_locs = sample_locs_4x_8x_16x;
+		sample_locs = sample_locs_16x;
 		break;
 	}
 
 	out_value[0] = (GET_SX(sample_locs, sample_index) + 8) / 16.0f;
 	out_value[1] = (GET_SY(sample_locs, sample_index) + 8) / 16.0f;
 }
 
 static void si_emit_max_4_sample_locs(struct radeon_cmdbuf *cs,
 				      uint64_t centroid_priority,
 				      uint32_t sample_locs)
@@ -165,27 +174,27 @@ void si_emit_sample_locations(struct radeon_cmdbuf *cs, int nr_samples)
 {
 	switch (nr_samples) {
 	default:
 	case 1:
 		si_emit_max_4_sample_locs(cs, centroid_priority_1x, sample_locs_1x);
 		break;
 	case 2:
 		si_emit_max_4_sample_locs(cs, centroid_priority_2x, sample_locs_2x);
 		break;
 	case 4:
-		si_emit_max_4_sample_locs(cs, centroid_priority_4x, sample_locs_4x_8x_16x[0]);
+		si_emit_max_4_sample_locs(cs, centroid_priority_4x, sample_locs_4x);
 		break;
 	case 8:
-		si_emit_max_16_sample_locs(cs, centroid_priority_8x, sample_locs_4x_8x_16x, 8);
+		si_emit_max_16_sample_locs(cs, centroid_priority_8x, sample_locs_8x, 8);
 		break;
 	case 16:
-		si_emit_max_16_sample_locs(cs, centroid_priority_16x, sample_locs_4x_8x_16x, 16);
+		si_emit_max_16_sample_locs(cs, centroid_priority_16x, sample_locs_16x, 16);
 		break;
 	}
 }
 
 void si_init_msaa_functions(struct si_context *sctx)
 {
 	int i;
 
 	sctx->b.get_sample_position = si_get_sample_position;
 
-- 
2.17.1