diff options
author | Brian Paul <brian.paul@tungstengraphics.com> | 2008-07-17 10:03:10 -0600 |
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committer | Brian Paul <brian.paul@tungstengraphics.com> | 2008-07-17 10:08:14 -0600 |
commit | d9f4d04111133a7dab5e645021e56245febea2ae (patch) | |
tree | 19c3909fa61b729013a28a691952823298f4a188 /src/mesa/shader/slang/library/slang_common_builtin.gc | |
parent | f49d345a51bb208fee19fc25762bcdb0e7f67174 (diff) |
mesa: fix/improve the atan(y,x) function
Diffstat (limited to 'src/mesa/shader/slang/library/slang_common_builtin.gc')
-rw-r--r-- | src/mesa/shader/slang/library/slang_common_builtin.gc | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/src/mesa/shader/slang/library/slang_common_builtin.gc b/src/mesa/shader/slang/library/slang_common_builtin.gc index b095a6434b..3726335471 100644 --- a/src/mesa/shader/slang/library/slang_common_builtin.gc +++ b/src/mesa/shader/slang/library/slang_common_builtin.gc @@ -401,16 +401,17 @@ vec4 atan(const vec4 y_over_x) float atan(const float y, const float x) { - if (x == 0.0) - return 0.0; - float z = atan(y / x); - if (x < 0.0) - { - if (y < 0.0) - return z - 3.141593; - return z + 3.141593; - } - return z; + float r; + if (abs(x) > 1.0e-4) { + r = atan(y / x); + if (x < 0.0) { + r = r + sign(y) * 3.141593; + } + } + else { + r = sign(y) * 1.5707965; // pi/2 + } + return r; } vec2 atan(const vec2 u, const vec2 v) |