mesa: Branch 'master'
Brian Paul
brianp at kemper.freedesktop.org
Tue May 1 20:03:06 UTC 2007
src/mesa/shader/slang/library/slang_common_builtin.gc | 23 ++++++++++--------
1 files changed, 14 insertions(+), 9 deletions(-)
New commits:
diff-tree 594b5ad87db09aef7fa2dc9f2d52e567ab92ff70 (from bfd5cf72c47646c0ae7e518d0a6adcbb81bd5e69)
Author: Brian <brian at yutani.localnet.net>
Date: Tue May 1 14:02:49 2007 -0600
implement acos(), asin(), atan()
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)
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