From 594b5ad87db09aef7fa2dc9f2d52e567ab92ff70 Mon Sep 17 00:00:00 2001 From: Brian Date: Tue, 1 May 2007 14:02:49 -0600 Subject: [PATCH] implement acos(), asin(), atan() --- .../shader/slang/library/slang_common_builtin.gc | 23 +++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/src/mesa/shader/slang/library/slang_common_builtin.gc b/src/mesa/shader/slang/library/slang_common_builtin.gc index a3d037c..04876ad 100644 --- a/src/mesa/shader/slang/library/slang_common_builtin.gc +++ b/src/mesa/shader/slang/library/slang_common_builtin.gc @@ -313,9 +313,16 @@ vec4 tan(const vec4 angle) float asin(const float x) { - // XXX FIX ME! - // __asm float_arcsine y, x; - __retVal = 0.5; + const float a0 = 1.5707288; // PI/2? + const float a1 = -0.2121144; + const float a2 = 0.0742610; + //const float a3 = -0.0187293; + const float halfPi = 3.1415926 * 0.5; + const float y = abs(x); + // three terms seem to be enough: + __retVal = (halfPi - sqrt(1.0 - y) * (a0 + y * (a1 + a2 * y))) * sign(x); + // otherwise, try four: + //__retVal = (halfPi - sqrt(1.0 - y) * (a0 + y * (a1 + y * (a2 + y * a3)))) * sign(x); } vec2 asin(const vec2 v) @@ -340,8 +347,8 @@ vec4 asin(const vec4 v) float acos(const float x) { - // XXX FIX ME! - __retVal = 0.5; + const float halfPi = 3.1415926 * 0.5; + __retVal = halfPi - asin(x); } vec2 acos(const vec2 v) @@ -365,11 +372,9 @@ vec4 acos(const vec4 v) __retVal.w = acos(v.w); } -float atan(const float y_over_x) +float atan(const float x) { - // XXX FIX ME - //__asm float_arctan z, y_over_x; - __retVal = 0.5; + __retVal = asin(x * inversesqrt(x * x + 1.0)); } vec2 atan(const vec2 y_over_x) -- 2.7.4