Computer Grpahics

Lighting GetPointLight(PointLight light, float3 pos3D, float3 viewDir, float3 normal)
{
	Lighting OUT;
	if (light.diffusePower > 0)
	{
		float3 lightDir = light.position - pos3D; //3D position in space of the surface
		float distance = length(lightDir);
		lightDir = lightDir / distance; // = normalize(lightDir);
		distance = distance * distance; //This line may be optimised using Inverse square root

		//Intensity of the diffuse light. Saturate to keep within the 0-1 range.
		float NdotL = dot(normal, lightDir);
		float intensity = saturate(NdotL);

		// Calculate the diffuse light factoring in light color, power and the attenuation
		OUT.Diffuse = intensity * light.diffuseColor * light.diffusePower / distance;

		//Calculate the half vector between the light vector and the view vector.
		//This is typically slower than calculating the actual reflection vector
		// due to the normalize function's reciprocal square root
		float3 H = normalize(lightDir + viewDir);

		//Intensity of the specular light
		float NdotH = dot(normal, H);
		intensity = pow(saturate(NdotH), specularHardness);

		//Sum up the specular light factoring
		OUT.Specular = intensity * light.specularColor * light.specularPower / distance; 
	}
	return OUT;
}