Avoid an undefined behaviour when frustumEdgeFalloff = 0

src/Shaders/ShadersInclude/shadowsFragmentFunctions.fx

@@ -10,7 +10,7 @@
 
     float computeFallOff(float value, vec2 clipSpace, float frustumEdgeFalloff)
     {
-        float mask = smoothstep(1.0 - frustumEdgeFalloff, 1.0, clamp(dot(clipSpace, clipSpace), 0., 1.));
+        float mask = smoothstep(1.0 - frustumEdgeFalloff, 1.00000012, clamp(dot(clipSpace, clipSpace), 0., 1.));
         return mix(value, 1.0, mask);
     }