If alpha testing is enabled, we need to include alpha in the FB write. Normally, this occurs as part of a color buffer write, but it's possible to use alpha testing without any color buffers. The alpha_test flag lets brw_fs.cpp know that the shader needs to send alpha anyway.
Since the flag's only use occurs when nr_color_buffers == 0, we don't need to set it in the general case; in fact, doing so will result in two indentical shaders being compiled, wasting time and program cache space. This patch also renames it to "alpha_only", since it no longer represents when alpha testing is enabled or disabled. Signed-off-by: Kenneth Graunke <[email protected]> --- src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 2 +- src/mesa/drivers/dri/i965/brw_wm.c | 7 ++++--- src/mesa/drivers/dri/i965/brw_wm.h | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp index 4f27a81..3db346c 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp @@ -2193,7 +2193,7 @@ fs_visitor::emit_fb_writes() } if (c->key.nr_color_regions == 0) { - if (c->key.alpha_test) { + if (c->key.alpha_only) { /* 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. diff --git a/src/mesa/drivers/dri/i965/brw_wm.c b/src/mesa/drivers/dri/i965/brw_wm.c index a169fd5..10f1dce 100644 --- a/src/mesa/drivers/dri/i965/brw_wm.c +++ b/src/mesa/drivers/dri/i965/brw_wm.c @@ -431,10 +431,8 @@ 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; @@ -529,6 +527,9 @@ static void brw_wm_populate_key( struct brw_context *brw, /* _NEW_BUFFERS */ key->nr_color_regions = ctx->DrawBuffer->_NumColorDrawBuffers; + /* _NEW_COLOR */ + key->alpha_only = ctx->Color.AlphaEnabled && key->nr_color_regions == 0; + /* CACHE_NEW_VS_PROG */ key->vp_outputs_written = brw->vs.prog_data->outputs_written; diff --git a/src/mesa/drivers/dri/i965/brw_wm.h b/src/mesa/drivers/dri/i965/brw_wm.h index 8f1cb8c..88f21d0 100644 --- a/src/mesa/drivers/dri/i965/brw_wm.h +++ b/src/mesa/drivers/dri/i965/brw_wm.h @@ -65,7 +65,7 @@ struct brw_wm_prog_key { GLuint flat_shade:1; GLuint nr_color_regions:5; GLuint render_to_fbo:1; - GLuint alpha_test:1; + GLuint alpha_only:1; /**< No color regions, but alpha testing enabled */ GLuint clamp_fragment_color:1; GLuint line_aa:2; -- 1.7.10.4 _______________________________________________ mesa-dev mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-dev
