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Spa8nky

[HLSL] Reflect function and specular light.

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Can anyone explain why the reflect funtion in HLSL produces specular light in the opposite direction to what it should be? Here I have my code for producing specular lighting:
	/* ===============================================
	 * --[Specular Light]-----------------------------
	 * ===============================================
	 * I = Si * Sc * (R.V)^n
	 * 
	 * Where:
	 *
	 * Si = Specular Intensity
	 * Sc = Specular Colour
	 * R = Reflection Vector = 2 * (N.L) * N-L  
	 *	   reflect(L, N) = L - 2 * N * dot(L, N) [HLSL Built-in Function]
	 * V = View Vector = Camera.WorldPosition - Pixel.WorldPosition
	 * n = Shininess factor
	 *
	 */
	 
	float Si = 1.0f;
	float4 Sc = float4(1.0f, 0.0f, 0.0f, 1.0f);
	float3 R = 	reflect(-L, N);					// normalize(2 * NdotL * N - L);		
	float RdotV = dot(V, R);
	float n = 15;
	float4 Specular_Light = Si * Sc * pow(saturate(RdotV), n);

If I use reflect(L, N) for my reflection vector then the reflection occurs in the opposite direction to the light direction. However, if I reverse the light direction in the reflect function (reflect(-L, N)) then the specular light is in the correct place. The light direction vector is correct for diffuse lighting but requires reversing for the reflect function. Why is this? Thanks

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This image shows what reflect() does

http://media.photobucket.com/image/reflect%20vector/jnosof/reflexion.png

In that image, reflect(R,N) returns L, which is exactly what it should return

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