// Light Computing
struct lightingInfo
{
	vec3 diffuse;
#ifdef SPECULARTERM
	vec3 specular;
#endif
#ifdef NDOTL
	float ndl;
#endif
};

lightingInfo computeLighting(vec3 viewDirectionW, vec3 vNormal, vec4 lightData, vec3 diffuseColor, vec3 specularColor, float range, float glossiness) {
	lightingInfo result;

	vec3 lightVectorW;
	float attenuation = 1.0;
	if (lightData.w == 0.)
	{
		vec3 direction = lightData.xyz - vPositionW;

		attenuation = max(0., 1.0 - length(direction) / range);
		lightVectorW = normalize(direction);
	}
	else
	{
		lightVectorW = normalize(-lightData.xyz);
	}

	// diffuse
	float ndl = max(0., dot(vNormal, lightVectorW));
#ifdef NDOTL
	result.ndl = ndl;
#endif
	result.diffuse = ndl * diffuseColor * attenuation;
#ifdef SPECULARTERM
	// Specular
	vec3 angleW = normalize(viewDirectionW + lightVectorW);
	float specComp = max(0., dot(vNormal, angleW));
	specComp = pow(specComp, max(1., glossiness));

	result.specular = specComp * specularColor * attenuation;
#endif
	return result;
}

lightingInfo computeSpotLighting(vec3 viewDirectionW, vec3 vNormal, vec4 lightData, vec4 lightDirection, vec3 diffuseColor, vec3 specularColor, float range, float glossiness) {
	lightingInfo result;

	vec3 direction = lightData.xyz - vPositionW;
	vec3 lightVectorW = normalize(direction);
	float attenuation = max(0., 1.0 - length(direction) / range);

	// diffuse
	float cosAngle = max(0., dot(lightDirection.xyz, -lightVectorW));

	if (cosAngle >= lightDirection.w)
	{
		cosAngle = max(0., pow(cosAngle, lightData.w));
		attenuation *= cosAngle;

		// Diffuse
		float ndl = max(0., dot(vNormal, lightVectorW));
#ifdef NDOTL
		result.ndl = ndl;
#endif
		result.diffuse = ndl * diffuseColor * attenuation;
#ifdef SPECULARTERM
		// Specular
		vec3 angleW = normalize(viewDirectionW + lightVectorW);
		float specComp = max(0., dot(vNormal, angleW));
		specComp = pow(specComp, max(1., glossiness));

		result.specular = specComp * specularColor * attenuation;
#endif
		return result;
	}

	result.diffuse = vec3(0.);
#ifdef SPECULARTERM
	result.specular = vec3(0.);
#endif
#ifdef NDOTL
	result.ndl = 0.;
#endif

	return result;
}

lightingInfo computeHemisphericLighting(vec3 viewDirectionW, vec3 vNormal, vec4 lightData, vec3 diffuseColor, vec3 specularColor, vec3 groundColor, float glossiness) {
	lightingInfo result;

	// Diffuse
	float ndl = dot(vNormal, lightData.xyz) * 0.5 + 0.5;
#ifdef NDOTL
	result.ndl = ndl;
#endif

	result.diffuse = mix(groundColor, diffuseColor, ndl);

#ifdef SPECULARTERM
	// Specular
	vec3 angleW = normalize(viewDirectionW + lightData.xyz);
	float specComp = max(0., dot(vNormal, angleW));
	specComp = pow(specComp, max(1., glossiness));

	result.specular = specComp * specularColor;
#endif
		return result;
}

#define inline
vec3 computeProjectionTextureDiffuseLighting(sampler2D projectionLightSampler, mat4 textureProjectionMatrix){
	vec4 strq = textureProjectionMatrix * vec4(vPositionW, 1.0);
	strq /= strq.w;
	return strq.xyz;
}