Fix IES profile light computation formula

Source/Shaders/IESProfile.hlsl

@@ -7,7 +7,7 @@
 float ComputeLightProfileMultiplier(Texture2D tex, float3 worldPosition, float3 lightPosition, float3 lightDirection)
 {
     float3 l = normalize(worldPosition - lightPosition);
-    float d = dot(lightPosition, lightDirection);
+    float d = dot(l, lightDirection);
     float angle = asin(d) / PI + 0.5f;
     return tex.SampleLevel(SamplerLinearClamp, float2(angle, 0), 0).r;
 }