From a99447314ca1cfce60f2a22285398fb222b2a440 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Fri, 11 Mar 2011 17:39:49 -0800 Subject: [PATCH] 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(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 7329f309f0f..2c997b4eb3a 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 ca17e80c8da..ca51d1599a4 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 d9cae75ab5b..90771e1f503 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; -- 2.30.2