r600g: fix alphatest without a colorbuffer on evergreen

diff --git a/src/gallium/drivers/r600/evergreen_state.c b/src/gallium/drivers/r600/evergreen_state.c
index d90ef3c..54438af 100644 (file)
--- a/src/gallium/drivers/r600/evergreen_state.c
+++ b/src/gallium/drivers/r600/evergreen_state.c
@@ -1701,7 +1701,10 @@ static void evergreen_emit_cb_misc_state(struct r600_context *rctx, struct r600_
 
        r600_write_context_reg_seq(cs, R_028238_CB_TARGET_MASK, 2);
        r600_write_value(cs, a->blend_colormask & fb_colormask); /* R_028238_CB_TARGET_MASK */
-       r600_write_value(cs, (a->dual_src_blend ? ps_colormask : 0) | fb_colormask); /* R_02823C_CB_SHADER_MASK */
+       /* Always enable the first colorbuffer in CB_SHADER_MASK. This
+        * will assure that the alpha-test will work even if there is
+        * no colorbuffer bound. */
+       r600_write_value(cs, 0xf | (a->dual_src_blend ? ps_colormask : 0) | fb_colormask); /* R_02823C_CB_SHADER_MASK */
 }
 
 static void evergreen_emit_db_misc_state(struct r600_context *rctx, struct r600_atom *atom)