Module: Mesa
Branch: master
Commit: a99447314ca1cfce60f2a22285398fb222b2a440
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=a99447314ca1cfce60f2a22285398fb222b2a440
Author: Eric Anholt <e...@anholt.net>
Date: Fri Mar 11 17:39:49 2011 -0800
i965: Fix alpha testing when there is no color buffer in the FBO.
We were alpha testing against an unwritten value, resulting in garbage.
(part of) Bug #35073.
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 11 +++++++++++
src/mesa/drivers/dri/i965/brw_wm.c | 1 +
src/mesa/drivers/dri/i965/brw_wm.h | 1 +
3 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 7329f30..2c997b4 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2140,6 +2140,17 @@ fs_visitor::emit_fb_writes()
}
if (c->key.nr_color_regions == 0) {
+ if (c->key.alpha_test && (this->frag_color || this->frag_data)) {
+ /* 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.
+ */
+ color.reg_offset += 3;
+ emit(fs_inst(BRW_OPCODE_MOV,
+ fs_reg(MRF, color_mrf + 3),
+ color));
+ }
+
fs_inst *inst = emit(fs_inst(FS_OPCODE_FB_WRITE,
reg_undef, reg_undef));
inst->base_mrf = 0;
diff --git a/src/mesa/drivers/dri/i965/brw_wm.c
b/src/mesa/drivers/dri/i965/brw_wm.c
index ca17e80..ca51d15 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.c
+++ b/src/mesa/drivers/dri/i965/brw_wm.c
@@ -284,6 +284,7 @@ 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 (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 d9cae75..90771e1 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.h
+++ b/src/mesa/drivers/dri/i965/brw_wm.h
@@ -64,6 +64,7 @@ struct brw_wm_prog_key {
GLuint linear_color:1; /**< linear interpolation vs perspective interp */
GLuint nr_color_regions:5;
GLuint render_to_fbo:1;
+ GLuint alpha_test:1;
GLbitfield proj_attrib_mask; /**< one bit per fragment program attribute */
GLuint shadowtex_mask:16;
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