On 05/11/2012 11:03 AM, Paul Berry wrote:
This patch modifies the function brw_blorp_blit_program::texel_fetch()
to emit the SI (sample index) argument to the SAMPLE_LD message when
reading from a sample index other than zero.
Previously we were using the ugly hack of configuring multisampled
source surfaces as single-sampled, and accessing sample indices other
than zero by swizzling the texture coordinates in the WM program.
---
src/mesa/drivers/dri/i965/brw_blorp.cpp | 7 +---
src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 45 ++++++++++++++++---------
2 files changed, 31 insertions(+), 21 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_blorp.cpp
b/src/mesa/drivers/dri/i965/brw_blorp.cpp
index 8e22511..f6aff44 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp.cpp
@@ -57,19 +57,16 @@ brw_blorp_surface_info::set(struct intel_mipmap_tree *mt,
unsigned int level, unsigned int layer)
{
brw_blorp_mip_info::set(mt, level, layer);
+ this->num_samples = mt->num_samples;
if (mt->format == MESA_FORMAT_S8) {
/* The miptree is a W-tiled stencil buffer. Surface states can't be set
* up for W tiling, so we'll need to use Y tiling and have the WM
- * program swizzle the coordinates. Furthermore, we need to set up the
- * surface state as single-sampled, because the memory layout of related
- * samples doesn't match between W and Y tiling.
+ * program swizzle the coordinates.
*/
this->map_stencil_as_y_tiled = true;
- this->num_samples = 0;
} else {
this->map_stencil_as_y_tiled = false;
- this->num_samples = mt->num_samples;
}
}
diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
index d3ab0ba..e985fad 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
@@ -220,6 +220,8 @@ enum sampler_message_arg
SAMPLER_MESSAGE_ARG_V_FLOAT,
SAMPLER_MESSAGE_ARG_U_INT,
SAMPLER_MESSAGE_ARG_V_INT,
+ SAMPLER_MESSAGE_ARG_SI_INT,
+ SAMPLER_MESSAGE_ARG_ZERO_INT,
};
/**
@@ -435,14 +437,6 @@ brw_blorp_blit_program::compile(struct brw_context *brw,
GLuint *program_size)
{
/* Sanity checks */
- if (key->src_tiled_w) {
- /* If the source image is W tiled, then tex_samples must be 0.
- * Otherwise, after conversion between W and Y tiling, there's no
- * guarantee that the sample index will be 0.
- */
- assert(key->tex_samples == 0);
- }
-
if (key->dst_tiled_w) {
/* If the destination image is W tiled, then dst_samples must be 0.
* Otherwise, after conversion between W and Y tiling, there's no
@@ -920,13 +914,15 @@ brw_blorp_blit_program::sample()
void
brw_blorp_blit_program::texel_fetch()
{
- static const sampler_message_arg args[2] = {
+ static const sampler_message_arg args[5] = {
SAMPLER_MESSAGE_ARG_U_INT,
- SAMPLER_MESSAGE_ARG_V_INT
+ SAMPLER_MESSAGE_ARG_V_INT,
+ SAMPLER_MESSAGE_ARG_ZERO_INT, /* R */
+ SAMPLER_MESSAGE_ARG_ZERO_INT, /* LOD */
+ SAMPLER_MESSAGE_ARG_SI_INT
};
- assert(s_is_zero);
- texture_lookup(GEN5_SAMPLER_MESSAGE_SAMPLE_LD, args, ARRAY_SIZE(args));
+ texture_lookup(GEN5_SAMPLER_MESSAGE_SAMPLE_LD, args, s_is_zero ? 2 : 5);
}
void
@@ -960,6 +956,15 @@ brw_blorp_blit_program::texture_lookup(GLuint msg_type,
case SAMPLER_MESSAGE_ARG_V_INT:
expand_to_32_bits(Y, mrf);
break;
+ case SAMPLER_MESSAGE_ARG_SI_INT:
+ if (s_is_zero)
+ brw_MOV(&func, mrf, brw_imm_ud(0));
+ else
+ expand_to_32_bits(S, mrf);
+ break;
It seems like up above you've guaranteed that you won't see
SAMPLER_MESSAGE_ARG_SI_INT when s_is_zero. Is this extra check necessary?
+ case SAMPLER_MESSAGE_ARG_ZERO_INT:
+ brw_MOV(&func, mrf, brw_imm_ud(0));
+ break;
}
mrf.nr += 2;
}
@@ -1060,14 +1065,22 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
intel_mipmap_tree *src_mt,
use_wm_prog = true;
memset(&wm_prog_key, 0, sizeof(wm_prog_key));
+ if (dst.map_stencil_as_y_tiled) {
+ /* If the destination surface is a W-tiled stencil buffer that we're
+ * mapping as Y tiled, then we need to set up the surface state as
+ * single-sampled, because the memory layout of related samples doesn't
+ * match between W and Y tiling.
+ */
+ dst.num_samples = 0;
+ }
+
if (src_mt->num_samples> 0&& dst_mt->num_samples> 0) {
/* We are blitting from a multisample buffer to a multisample buffer, so
* we must preserve samples within a pixel. This means we have to
- * configure the render target and texture surface states as
- * single-sampled, so that the WM program can access each sample
- * individually.
+ * configure the render target as single-sampled, so that the WM program
+ * generate each sample separately.
*/
- src.num_samples = dst.num_samples = 0;
+ dst.num_samples = 0;
}
/* The render path must be configured to use the same number of samples as
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