Check the distance against epsilon to determine if it matches

Alc/ALu.c

@@ -732,7 +732,7 @@ ALvoid CalcSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         /* Use a binaural HRTF algorithm for stereo headphone playback */
         ALfloat delta, ev = 0.0f, az = 0.0f;
 
-        if(Distance > 0.0f)
+        if(Distance > FLT_EPSILON)
         {
             ALfloat invlen = 1.0f/Distance;
             Position[0] *= invlen;
@@ -797,7 +797,7 @@ ALvoid CalcSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         }
 
         /* Normalize the length, and compute panned gains. */
-        if(Distance > 0.0f)
+        if(Distance > FLT_EPSILON)
         {
             ALfloat invlen = 1.0f/Distance;
             Position[0] *= invlen;

OpenAL32/Include/alu.h

@@ -16,6 +16,11 @@
 #define F_PI    (3.14159265358979323846f)  /* pi */
 #define F_PI_2  (1.57079632679489661923f)  /* pi/2 */
 
+#ifndef FLT_EPSILON
+#define FLT_EPSILON (1.19209290e-07f)
+#endif
+
+
 #ifndef HAVE_POWF
 static __inline float powf(float x, float y)
 { return (float)pow(x, y); }