From bc6751237c7cdd0277bd0dc864a207f200258201 Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Thu, 28 Jun 2012 17:26:00 -0700
Subject: [PATCH] Clamp the Y position before trying to get the elevation

---
 Alc/ALu.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Alc/ALu.c b/Alc/ALu.c
index d3965dfd..7fac1771 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -677,8 +677,9 @@ ALvoid CalcSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
 
             /* Calculate elevation and azimuth only when the source is not at
              * the listener. This prevents +0 and -0 Z from producing
-             * inconsistent panning. */
-            ev = aluAsin(Position[1]);
+             * inconsistent panning. Also, clamp Y in case FP precision errors
+             * cause it to land outside of -1..+1. */
+            ev = aluAsin(clampf(Position[1], -1.0f, 1.0f));
             az = aluAtan2(Position[0], -Position[2]*ZScale);
         }
 
-- 
2.11.4.GIT