From 3d038a3ed2d8325c4b826f13b62398b3ed33f3ba Mon Sep 17 00:00:00 2001
From: Brian Paul <brianp@vmware.com>
Date: Thu, 5 Aug 2010 16:38:22 -0600
Subject: [PATCH] glsl: fix atan(0, -1)

Fixes fd.o bug 29388

NOTE: this is a candidate for the 7.8 branch.
---
 src/mesa/slang/library/slang_common_builtin.gc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/slang/library/slang_common_builtin.gc b/src/mesa/slang/library/slang_common_builtin.gc
index d75354deffe..1f5ddbc1ee2 100644
--- a/src/mesa/slang/library/slang_common_builtin.gc
+++ b/src/mesa/slang/library/slang_common_builtin.gc
@@ -411,7 +411,7 @@ float atan(const float y, const float x)
    if (abs(x) > 1.0e-4) {
       r = atan(y / x);
       if (x < 0.0) {
-         r = r + sign(y) * 3.141593;
+         r = r + 3.141593 - 6.283186 * float(y < 0.0);
       }
    }
    else {
-- 
2.30.2