On 05/11/2012 11:03 AM, Paul Berry wrote:
This patch modifies the "blorp" WM program so that it can be run in
MSDISPMODE_PERSAMPLE (which means that every single sample of a
multisampled render target is dispatched to the WM program, not just
every pixel).
Previously we were using the ugly hack of configuring multisampled
destination surfaces as single-sampled, and generating sample indices
other than zero by swizzling the pixel coordinates in the WM program.
---
src/mesa/drivers/dri/i965/brw_blorp.h | 12 ++++
src/mesa/drivers/dri/i965/brw_blorp_blit.cpp | 87 +++++++++++++++++++-------
src/mesa/drivers/dri/i965/gen6_blorp.cpp | 5 +-
src/mesa/drivers/dri/i965/gen7_blorp.cpp | 10 ++-
4 files changed, 87 insertions(+), 27 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_blorp.h
b/src/mesa/drivers/dri/i965/brw_blorp.h
index f14a5c7..b911356 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp.h
+++ b/src/mesa/drivers/dri/i965/brw_blorp.h
@@ -132,6 +132,12 @@ const unsigned int BRW_BLORP_NUM_PUSH_CONST_REGS =
struct brw_blorp_prog_data
{
unsigned int first_curbe_grf;
+
+ /**
+ * True if the WM program should be run in MSDISPMODE_PERSAMPLE with more
+ * than one sample per pixel.
+ */
+ bool persample_msaa_dispatch;
};
class brw_blorp_params
@@ -218,6 +224,12 @@ struct brw_blorp_blit_prog_key
* pixels that are outside the destination rectangle.
*/
bool use_kill;
+
+ /**
+ * True if the WM program should be run in MSDISPMODE_PERSAMPLE with more
+ * than one sample per pixel.
+ */
+ bool persample_msaa_dispatch;
};
class brw_blorp_blit_params : public brw_blorp_params
diff --git a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
index e985fad..07e9dd7 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp_blit.cpp
@@ -437,13 +437,14 @@ brw_blorp_blit_program::compile(struct brw_context *brw,
GLuint *program_size)
{
/* Sanity checks */
- 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
+ if (key->dst_tiled_w&& key->rt_samples> 0) {
+ /* If the destination image is W tiled and multisampled, then the thread
+ * must be dispatched once per sample, not once per pixel. This is
+ * necessary because after conversion between W and Y tiling, there's no
* guarantee that all samples corresponding to a single pixel will still
* be together.
*/
- assert(key->rt_samples == 0);
+ assert(key->persample_msaa_dispatch);
}
if (key->blend) {
@@ -459,6 +460,17 @@ brw_blorp_blit_program::compile(struct brw_context *brw,
assert(key->tex_samples> 0);
}
+ if (key->persample_msaa_dispatch) {
+ /* It only makes sense to do persample dispatch if the render target is
+ * configured as multisampled.
+ */
+ assert(key->rt_samples> 0);
+ }
+
+ /* Set up prog_data */
+ memset(&prog_data, 0, sizeof(prog_data));
+ prog_data.persample_msaa_dispatch = key->persample_msaa_dispatch;
+
brw_set_compression_control(&func, BRW_COMPRESSION_NONE);
alloc_regs();
@@ -658,11 +670,29 @@ brw_blorp_blit_program::compute_frag_coords()
*/
brw_ADD(&func, Y, stride(suboffset(R1, 5), 2, 4, 0),
brw_imm_v(0x11001100));
- /* Since we always run the WM in a mode that causes a single fragment
- * dispatch per pixel, it's not meaningful to compute a sample value. Just
- * set it to 0.
- */
- s_is_zero = true;
+ if (key->persample_msaa_dispatch) {
+ /* The WM will be run in MSDISPMODE_PERSAMPLE with num_samples> 0.
+ * Therefore, subspan 0 will represent sample 0, subspan 1 will
+ * represent sample 1, and so on.
+ *
+ * So we need to populate S with the sequence (0, 0, 0, 0, 1, 1, 1, 1,
+ * 2, 2, 2, 2, 3, 3, 3, 3). The easiest way to do this is to populate a
+ * temporary variable with the sequence (0, 1, 2, 3), and then copy from
+ * it using vstride=1, width=4, hstride=0.
+ *
+ * TODO: implement appropriate calculation for Gen7.
+ */
I think you mean:
TODO: implement the necessary calculation for 8x multisampling.
Otherwise,
Reviewed-by: Kenneth Graunke <kenn...@whitecape.org>
+ brw_MOV(&func, t1, brw_imm_v(0x3210));
+ brw_MOV(&func, S, stride(t1, 1, 4, 0));
+ s_is_zero = false;
+ } else {
+ /* Either the destination surface is single-sampled, or the WM will be
+ * run in MSDISPMODE_PERPIXEL (which causes a single fragment dispatch
+ * per pixel). In either case, it's not meaningful to compute a sample
+ * value. Just set it to 0.
+ */
+ s_is_zero = true;
+ }
}
/**
@@ -1065,22 +1095,23 @@ 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.
+ if (dst.map_stencil_as_y_tiled&& dst.num_samples> 0) {
+ /* If the destination surface is a W-tiled multisampled stencil buffer
+ * that we're mapping as Y tiled, then we need to arrange for the WM
+ * program to run once per sample rather than once per pixel, because
+ * the memory layout of related samples doesn't match between W and Y
+ * tiling.
*/
- dst.num_samples = 0;
+ wm_prog_key.persample_msaa_dispatch = true;
}
- if (src_mt->num_samples> 0&& dst_mt->num_samples> 0) {
+ if (src.num_samples> 0&& dst.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 as single-sampled, so that the WM program
- * generate each sample separately.
+ * arrange for the WM program to run once per sample rather than once
+ * per pixel.
*/
- dst.num_samples = 0;
+ wm_prog_key.persample_msaa_dispatch = true;
}
/* The render path must be configured to use the same number of samples as
@@ -1138,12 +1169,22 @@ brw_blorp_blit_params::brw_blorp_blit_params(struct
intel_mipmap_tree *src_mt,
* dimensions 64x64. We must also align it to a multiple of the tile
* size, because the differences between W and Y tiling formats will
* mean that pixels are scrambled within the tile.
+ *
+ * Note: if the destination surface configured as an MSAA surface, then
+ * the effective tile size we need to align it to is smaller, because
+ * each pixel covers a 2x2 or a 4x2 block of samples.
+ *
* TODO: what if this makes the coordinates too large?
*/
- x0 = (x0 * 2)& ~127;
- y0 = (y0 / 2)& ~31;
- x1 = ALIGN(x1 * 2, 128);
- y1 = ALIGN(y1 / 2, 32);
+ unsigned x_align = 64, y_align = 64;
+ if (dst_mt->num_samples> 0) {
+ x_align /= (dst_mt->num_samples == 4 ? 2 : 4);
+ y_align /= 2;
+ }
+ x0 = (x0& ~(x_align - 1)) * 2;
+ y0 = (y0& ~(y_align - 1)) / 2;
+ x1 = ALIGN(x1, x_align) * 2;
+ y1 = ALIGN(y1, y_align) / 2;
wm_prog_key.use_kill = true;
}
}
diff --git a/src/mesa/drivers/dri/i965/gen6_blorp.cpp
b/src/mesa/drivers/dri/i965/gen6_blorp.cpp
index 8eed9dc..85a8ee6 100644
--- a/src/mesa/drivers/dri/i965/gen6_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/gen6_blorp.cpp
@@ -742,7 +742,10 @@ gen6_blorp_emit_wm_config(struct brw_context *brw,
if (params->num_samples> 0) {
dw6 |= GEN6_WM_MSRAST_ON_PATTERN;
- dw6 |= GEN6_WM_MSDISPMODE_PERPIXEL;
+ if (prog_data&& prog_data->persample_msaa_dispatch)
+ dw6 |= GEN6_WM_MSDISPMODE_PERSAMPLE;
+ else
+ dw6 |= GEN6_WM_MSDISPMODE_PERPIXEL;
} else {
dw6 |= GEN6_WM_MSRAST_OFF_PIXEL;
dw6 |= GEN6_WM_MSDISPMODE_PERSAMPLE;
diff --git a/src/mesa/drivers/dri/i965/gen7_blorp.cpp
b/src/mesa/drivers/dri/i965/gen7_blorp.cpp
index fbb94df..e5b27dd 100644
--- a/src/mesa/drivers/dri/i965/gen7_blorp.cpp
+++ b/src/mesa/drivers/dri/i965/gen7_blorp.cpp
@@ -399,7 +399,8 @@ gen7_blorp_emit_sf_config(struct brw_context *brw,
*/
static void
gen7_blorp_emit_wm_config(struct brw_context *brw,
- const brw_blorp_params *params)
+ const brw_blorp_params *params,
+ brw_blorp_prog_data *prog_data)
{
struct intel_context *intel =&brw->intel;
@@ -431,7 +432,10 @@ gen7_blorp_emit_wm_config(struct brw_context *brw,
if (params->num_samples> 0) {
dw1 |= GEN7_WM_MSRAST_ON_PATTERN;
- dw2 |= GEN7_WM_MSDISPMODE_PERPIXEL;
+ if (prog_data&& prog_data->persample_msaa_dispatch)
+ dw2 |= GEN7_WM_MSDISPMODE_PERSAMPLE;
+ else
+ dw2 |= GEN7_WM_MSDISPMODE_PERPIXEL;
} else {
dw1 |= GEN7_WM_MSRAST_OFF_PIXEL;
dw2 |= GEN7_WM_MSDISPMODE_PERSAMPLE;
@@ -757,7 +761,7 @@ gen7_blorp_exec(struct intel_context *intel,
gen7_blorp_emit_streamout_disable(brw, params);
gen6_blorp_emit_clip_disable(brw, params);
gen7_blorp_emit_sf_config(brw, params);
- gen7_blorp_emit_wm_config(brw, params);
+ gen7_blorp_emit_wm_config(brw, params, prog_data);
if (params->use_wm_prog) {
gen7_blorp_emit_binding_table_pointers_ps(brw, params,
wm_bind_bo_offset);
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