diff options
| -rw-r--r-- | src/gallium/drivers/llvmpipe/lp_state_setup.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/src/gallium/drivers/llvmpipe/lp_state_setup.c b/src/gallium/drivers/llvmpipe/lp_state_setup.c index cecfbcebe61..dab5096c61d 100644 --- a/src/gallium/drivers/llvmpipe/lp_state_setup.c +++ b/src/gallium/drivers/llvmpipe/lp_state_setup.c @@ -182,9 +182,17 @@ 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 face_val = LLVMBuildFSub(builder, a0_0f, - lp_build_const_float(gallivm, 0.5), - ""); + /* Our face val is either 1 or 0 so we do + * face = (val * 2) - 1 + * to make it 1 or -1 + */ + LLVMValueRef face_val = + LLVMBuildFAdd(builder, + LLVMBuildFMul(builder, a0_0f, + lp_build_const_float(gallivm, 2.0), + ""), + lp_build_const_float(gallivm, -1.0), + ""); LLVMValueRef a0 = vec4f(gallivm, face_val, zero, zero, zero, "facing"); LLVMValueRef zerovec = vec4f_from_scalar(gallivm, zero, "zero"); |