#version 330

in vec4 diffuseColor;
in vec3 vertexNormal;
in vec3 cameraSpacePosition;

out vec4 outputColor;

uniform vec3 modelSpaceLightPos;

uniform vec4 lightIntensity;
uniform vec4 ambientIntensity;

uniform vec3 cameraSpaceLightPos;

uniform float lightAttenuation;

vec4 ApplyLightIntensity(in vec3 cameraSpacePosition, out vec3 lightDirection)
{
	vec3 lightDifference =  cameraSpaceLightPos - cameraSpacePosition;
	float lightDistanceSqr = dot(lightDifference, lightDifference);
	lightDirection = lightDifference * inversesqrt(lightDistanceSqr);
	
	return lightIntensity * (1 / ( 1.0 + lightAttenuation * sqrt(lightDistanceSqr)));
}

void main()
{
	vec3 lightDir = vec3(0.0);
	vec4 attenIntensity = ApplyLightIntensity(cameraSpacePosition, lightDir);

	float cosAngIncidence = dot(normalize(vertexNormal), lightDir);
	cosAngIncidence = clamp(cosAngIncidence, 0, 1);
	
	outputColor = (diffuseColor * attenIntensity * cosAngIncidence) +
		(diffuseColor * ambientIntensity);
}
