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authorKenneth Graunke <[email protected]>2012-07-12 11:25:58 -0700
committerKenneth Graunke <[email protected]>2012-07-12 13:35:46 -0700
commit86e401b771ce4a6f9a728f76c5061c339f012d0a (patch)
treebe142dab4d8d1dac280824efd9229deebff5cb5e /src/mesa/drivers/dri
parent16060531baa837304eb7a427d0cdbeccd95cf09a (diff)
i965: Always emit alpha when nr_color_buffers == 0.
If alpha-testing is enabled, we need to send alpha down the pipeline even if nr_color_buffers == 0. However, tracking whether alpha-testing is enabled in the WM program key is expensive: it causes us to compile multiple specializations of the same shader, using program cache space. This patch removes the check for alpha-testing, and simply emits alpha whenever nr_color_buffers == 0. We believe this will also be necessary for alpha-to-coverage, and it should add minimal overhead to an uncommon case. Saving the recompiles should more than make up the difference. Reviewed-by: Eric Anholt <[email protected]> Signed-off-by: Kenneth Graunke <[email protected]>
Diffstat (limited to 'src/mesa/drivers/dri')
-rw-r--r--src/mesa/drivers/dri/i965/brw_fs_visitor.cpp12
-rw-r--r--src/mesa/drivers/dri/i965/brw_wm.c4
-rw-r--r--src/mesa/drivers/dri/i965/brw_wm.h1
3 files changed, 6 insertions, 11 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 7224cbe04f5..08c0130aa3e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -2141,13 +2141,11 @@ fs_visitor::emit_fb_writes()
}
if (c->key.nr_color_regions == 0) {
- if (c->key.alpha_test) {
- /* If the alpha test is enabled but there's no color buffer,
- * we still need to send alpha out the pipeline to our null
- * renderbuffer.
- */
- emit_color_write(0, 3, color_mrf);
- }
+ /* Even if there's no color buffers enabled, we still need to send
+ * alpha out the pipeline to our null renderbuffer to support
+ * alpha-testing, alpha-to-coverage, and so on.
+ */
+ emit_color_write(0, 3, color_mrf);
fs_inst *inst = emit(FS_OPCODE_FB_WRITE);
inst->base_mrf = base_mrf;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c
index 880564619c8..7194a739d08 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -449,10 +449,8 @@ static void brw_wm_populate_key( struct brw_context *brw,
/* Build the index for table lookup
*/
- /* _NEW_COLOR */
- key->alpha_test = ctx->Color.AlphaEnabled;
-
if (intel->gen < 6) {
+ /* _NEW_COLOR */
if (fp->program.UsesKill || ctx->Color.AlphaEnabled)
lookup |= IZ_PS_KILL_ALPHATEST_BIT;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.h b/src/mesa/drivers/dri/i965/brw_wm.h
index 2cde2a0f537..b976a605cb6 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.h
+++ b/src/mesa/drivers/dri/i965/brw_wm.h
@@ -65,7 +65,6 @@ struct brw_wm_prog_key {
GLuint flat_shade:1;
GLuint nr_color_regions:5;
GLuint render_to_fbo:1;
- GLuint alpha_test:1;
GLuint clamp_fragment_color:1;
GLuint line_aa:2;