[Mesa-dev] [PATCH 0.2/2] i965: Initialize the sample_map_Xx variables
Anuj Phogat
anuj.phogat at gmail.com
Tue Sep 23 17:41:21 PDT 2014
Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
---
src/mesa/drivers/dri/i965/brw_context.c | 36 +++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 619f2d5..cabc79f 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -406,6 +406,42 @@ brw_initialize_context_constants(struct brw_context *brw)
ctx->Const.MaxDepthTextureSamples = max_samples;
ctx->Const.MaxIntegerSamples = max_samples;
+ /* 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 index to a sample number.
+ */
+ ctx->Const.sample_map_2x = "0, 1";
+ ctx->Const.sample_map_4x = "0, 1, 2, 3";
+ ctx->Const.sample_map_8x = "5, 2, 4, 6, 0, 3, 7, 1";
+
if (brw->gen >= 7)
ctx->Const.MaxProgramTextureGatherComponents = 4;
else if (brw->gen == 6)
--
1.9.3
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