Vector4 DiffuseIBL(Vector2 Random, Vector3 N, BitmapData &img, bool hdr){
	Vector4 DiffuseLighting;
	unsigned NumSamples = 4096 * 2;
	//for i in range(NumSamples) :
	for (unsigned int i = 0; i < NumSamples; i++){
		Vector2 E = Hammersley(i, NumSamples, Random);
		Vector3 C = CosineSampleHemisphere(E);
		Vector3 L = TangentToWorld(C, N);

		float NoL = saturate(N.dot(L));;
		//#print("NoL", NoL);
		if (NoL > 0){
			Vector2 uv2 = pos2uv(L);
			Vector4 result = img.getPixel32Int(uv2.x * img.width, uv2.y * img.height);
			//#lambert = DiffuseColor * NoL / PI
			//#pdf = NoL / PI
			float e = 1.0;
			if (hdr)
			{
				e = result.w - 128.0;
				e = pow(2, e);
			}
			
			DiffuseLighting.x += result.x * e;
			DiffuseLighting.y += result.y * e;
			DiffuseLighting.z += result.z * e;
			DiffuseLighting.w += 255;
		}
	}
	float Weight = 1.0 / NumSamples;
	DiffuseLighting = DiffuseLighting * (Weight);
	return DiffuseLighting;
}