#version 330 core

in vec3 view_position;
in vec3 view_normal;

struct DirectionalLight {
	// direction in view space
	vec3 direction;
	vec3 ambient;
	vec3 diffuse;
	vec3 specular;
};
uniform DirectionalLight global_light = DirectionalLight(
	vec3(0.57735026918962576451),
	vec3(0.1),
	vec3(1.0),
	vec3(1.0)
);


void main() {
	// TODO: pull from texture (or some other source)
	const vec3 material_color = vec3(1.0);

	vec3 normal = normalize(view_normal);
	float cos_theta = dot(normal, global_light.direction);
	float cos_alpha = dot(-normalize(view_position), reflect(-global_light.direction, normal));

	vec3 ambient = global_light.ambient * material_color;
	vec3 diffuse = global_light.diffuse * material_color * max(0.0, cos_theta);
	vec3 specular = global_light.specular * pow(max(0.0, cos_alpha), 5);

	gl_FragColor = vec4(ambient + diffuse + specular, 1.0);
}