#version 330

uniform sampler2D texture0;
uniform vec4 colDiffuse;

uniform vec3 sun_direction;
uniform vec3 sun_colour;
uniform float sun_intensity;

uniform vec3 moon_direction;
uniform vec3 moon_colour;
uniform float moon_intensity;

uniform vec3 ambient_colour;
uniform float ambient_intensity;

in vec2 frag_texcoord;
in vec4 frag_colour;
in vec3 frag_world_normal;

out vec4 finalColor;

void
main()
{
	vec3 normal = normalize(frag_world_normal);

	// float sun_diffuse = max(
	// 	dot(normal, sun_direction),
	// 	0.0
	// );

	// half lambert
	float sun_diffuse = dot(normal, sun_direction) * 0.5 + 0.5;
	sun_diffuse *= sun_diffuse;

	float moon_diffuse = max(
		dot(normal, moon_direction),
		0.0
	);

	vec3 ambient_light =
		ambient_colour * ambient_intensity;

	vec3 sun_light =
		sun_colour *
		sun_intensity *
		sun_diffuse;

	vec3 moon_light =
		moon_colour *
		moon_intensity *
		moon_diffuse;

	vec3 lighting =
		ambient_light +
		sun_light +
		moon_light;

	vec4 texel =
		texture(texture0, frag_texcoord) *
		colDiffuse *
		frag_colour;

	finalColor = vec4(
		texel.rgb * max(lighting, vec3(0.0)),
		texel.a
	);
}