Mesa (9.2): i965: Gen4-5: Don't enable hardware alpha test with MRT

[Carl Worth]

Module: Mesa
Branch: 9.2
Commit: 711b15ddb9c7ba74dfcf667e8f8ace9d11e58746
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=711b15ddb9c7ba74dfcf667e8f8ace9d11e58746

Author: Chris Forbes <chrisf at ijw.co.nz>
Date:   Sun Oct 27 12:09:51 2013 +1300

i965: Gen4-5: Don't enable hardware alpha test with MRT

We have to do this in the shader instead, since these gens lack an
independent RT0 alpha value in their render target write messages.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
Reviewed-by: Eric Anholt <eric at anholt.net>
(cherry picked from commit dbcd633040939565f91eedac6ea313503ac9f0a5)

---

 src/mesa/drivers/dri/i965/brw_cc.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_cc.c b/src/mesa/drivers/dri/i965/brw_cc.c
index 6f85f63..53466e7 100644
--- a/src/mesa/drivers/dri/i965/brw_cc.c
+++ b/src/mesa/drivers/dri/i965/brw_cc.c
@@ -187,7 +187,8 @@ static void upload_cc_unit(struct brw_context *brw)
 				eqA != eqRGB);
    }
 
-   if (ctx->Color.AlphaEnabled) {
+   /* _NEW_BUFFERS */
+   if (ctx->Color.AlphaEnabled && ctx->DrawBuffer->_NumColorDrawBuffers <= 1) {
       cc->cc3.alpha_test = 1;
       cc->cc3.alpha_test_func =
 	 intel_translate_compare_func(ctx->Color.AlphaFunc);