From a6046d217d14130a46f6ffe42992fd745551a928 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Wed, 2 Mar 2016 23:50:04 -0800 Subject: [PATCH] glsl: Improve the accuracy of the acos() approximation. The adjusted polynomial coefficients come from the numerical minimization of the L2 norm of the relative error. The old coefficients would give a maximum relative error of about 15000 ULP in the neighborhood around acos(x) = 0, the new ones give a relative error bounded by less than 2000 ULP in the same neighborhood. Fixes four dEQP subtests: dEQP-GLES31.functional.shaders.builtin_functions.precision.acos. highp_compute.{scalar,vec2,vec3,vec4} Signed-off-by: Kenneth Graunke Reviewed-by: Iago Toral Quiroga Reviewed-by: Francisco Jerez --- src/compiler/glsl/builtin_functions.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/compiler/glsl/builtin_functions.cpp b/src/compiler/glsl/builtin_functions.cpp index 0d289c1615c..10fb21b9a0d 100644 --- a/src/compiler/glsl/builtin_functions.cpp +++ b/src/compiler/glsl/builtin_functions.cpp @@ -3262,7 +3262,7 @@ builtin_builder::_acos(const glsl_type *type) ir_variable *x = in_var(type, "x"); MAKE_SIG(type, always_available, 1, x); - body.emit(ret(sub(imm(M_PI_2f), asin_expr(x, 0.086566724f, -0.03102955f)))); + body.emit(ret(sub(imm(M_PI_2f), asin_expr(x, 0.08132463f, -0.02363318f)))); return sig; } -- 2.30.2