From 2d15f4746ba4c5d0146912550442b96386e4a32d Mon Sep 17 00:00:00 2001 From: Zack Rusin Date: Fri, 2 Aug 2013 15:50:16 -0400 Subject: [PATCH] llvmpipe: make the front-face behavior match the gallium spec The spec says that front-face is true if the value is >0 and false if it's <0. To make sure that we follow the spec, lets just subtract 0.5 from our value (llvmpipe did 1 for frontface and 0 otherwise), which will get us a positive num for frontface and negative for backface. Signed-off-by: Zack Rusin Reviewed-by: Roland Scheidegger Reviewed-by: Jose Fonseca --- src/gallium/drivers/llvmpipe/lp_state_setup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/gallium/drivers/llvmpipe/lp_state_setup.c b/src/gallium/drivers/llvmpipe/lp_state_setup.c index bb5cfc4be46..cecfbcebe61 100644 --- a/src/gallium/drivers/llvmpipe/lp_state_setup.c +++ b/src/gallium/drivers/llvmpipe/lp_state_setup.c @@ -182,7 +182,10 @@ emit_facing_coef(struct gallivm_state *gallivm, LLVMValueRef a0_0 = args->facing; LLVMValueRef a0_0f = LLVMBuildSIToFP(builder, a0_0, float_type, ""); LLVMValueRef zero = lp_build_const_float(gallivm, 0.0); - LLVMValueRef a0 = vec4f(gallivm, a0_0f, zero, zero, zero, "facing"); + LLVMValueRef face_val = LLVMBuildFSub(builder, a0_0f, + lp_build_const_float(gallivm, 0.5), + ""); + LLVMValueRef a0 = vec4f(gallivm, face_val, zero, zero, zero, "facing"); LLVMValueRef zerovec = vec4f_from_scalar(gallivm, zero, "zero"); store_coef(gallivm, args, slot, a0, zerovec, zerovec); -- 2.11.0