From 7a75e7d6e85d27e102ff7e15583c33b1ce282fe4 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jos=C3=A9=20Fonseca?= Date: Tue, 22 May 2012 16:04:33 +0100 Subject: [PATCH] llvmpipe: Fix alpha testing precision on rgba8 formats. This is a long standing problem, that recently surfaced with the change to enable perspective correct color interpolation. A fix for all possible formats is left to the future. Reviewed-by: Brian Paul Reviewed-by: Roland Scheidegger --- src/gallium/drivers/llvmpipe/lp_bld_alpha.c | 28 ++++++++++++++++++++++++++++ src/gallium/drivers/llvmpipe/lp_bld_alpha.h | 2 ++ src/gallium/drivers/llvmpipe/lp_state_fs.c | 5 ++++- 3 files changed, 34 insertions(+), 1 deletion(-) diff --git a/src/gallium/drivers/llvmpipe/lp_bld_alpha.c b/src/gallium/drivers/llvmpipe/lp_bld_alpha.c index 518969c..6e2d037 100644 --- a/src/gallium/drivers/llvmpipe/lp_bld_alpha.c +++ b/src/gallium/drivers/llvmpipe/lp_bld_alpha.c @@ -32,9 +32,12 @@ */ #include "pipe/p_state.h" +#include "util/u_format.h" #include "gallivm/lp_bld_type.h" #include "gallivm/lp_bld_const.h" +#include "gallivm/lp_bld_arit.h" +#include "gallivm/lp_bld_conv.h" #include "gallivm/lp_bld_logic.h" #include "gallivm/lp_bld_flow.h" #include "gallivm/lp_bld_debug.h" @@ -46,6 +49,7 @@ void lp_build_alpha_test(struct gallivm_state *gallivm, unsigned func, struct lp_type type, + const struct util_format_description *cbuf_format_desc, struct lp_build_mask_context *mask, LLVMValueRef alpha, LLVMValueRef ref, @@ -56,6 +60,30 @@ lp_build_alpha_test(struct gallivm_state *gallivm, lp_build_context_init(&bld, gallivm, type); + /* + * Alpha testing needs to be done in the color buffer precision. + * + * TODO: Ideally, instead of duplicating the color conversion code, we would do + * alpha testing after converting the output colors, but that's not very + * convenient, because it needs to be done before depth testing. Hopefully + * LLVM will detect and remove the duplicate expression. + * + * FIXME: This should be generalized to formats other than rgba8 variants. + */ + if (type.floating && + util_format_is_rgba8_variant(cbuf_format_desc)) { + const unsigned dst_width = 8; + + alpha = lp_build_clamp(&bld, alpha, bld.zero, bld.one); + ref = lp_build_clamp(&bld, ref, bld.zero, bld.one); + + alpha = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, alpha); + ref = lp_build_clamped_float_to_unsigned_norm(gallivm, type, dst_width, ref); + + type.floating = 0; + lp_build_context_init(&bld, gallivm, type); + } + test = lp_build_cmp(&bld, func, alpha, ref); lp_build_name(test, "alpha_mask"); diff --git a/src/gallium/drivers/llvmpipe/lp_bld_alpha.h b/src/gallium/drivers/llvmpipe/lp_bld_alpha.h index 06206a2..15f1284 100644 --- a/src/gallium/drivers/llvmpipe/lp_bld_alpha.h +++ b/src/gallium/drivers/llvmpipe/lp_bld_alpha.h @@ -39,6 +39,7 @@ #include "gallivm/lp_bld.h" struct pipe_alpha_state; +struct util_format_description; struct gallivm_state; struct lp_type; struct lp_build_mask_context; @@ -48,6 +49,7 @@ void lp_build_alpha_test(struct gallivm_state *gallivm, unsigned func, struct lp_type type, + const struct util_format_description *cbuf_format_desc, struct lp_build_mask_context *mask, LLVMValueRef alpha, LLVMValueRef ref, diff --git a/src/gallium/drivers/llvmpipe/lp_state_fs.c b/src/gallium/drivers/llvmpipe/lp_state_fs.c index 11a3871..0bdc17f 100644 --- a/src/gallium/drivers/llvmpipe/lp_state_fs.c +++ b/src/gallium/drivers/llvmpipe/lp_state_fs.c @@ -345,13 +345,16 @@ generate_fs(struct gallivm_state *gallivm, 0); if (color0 != -1 && outputs[color0][3]) { + const struct util_format_description *cbuf_format_desc; LLVMValueRef alpha = LLVMBuildLoad(builder, outputs[color0][3], "alpha"); LLVMValueRef alpha_ref_value; alpha_ref_value = lp_jit_context_alpha_ref_value(gallivm, context_ptr); alpha_ref_value = lp_build_broadcast(gallivm, vec_type, alpha_ref_value); - lp_build_alpha_test(gallivm, key->alpha.func, type, + cbuf_format_desc = util_format_description(key->cbuf_format[0]); + + lp_build_alpha_test(gallivm, key->alpha.func, type, cbuf_format_desc, &mask, alpha, alpha_ref_value, (depth_mode & LATE_DEPTH_TEST) != 0); } -- 2.7.4