#version 330

in vec3 vertexPosition;
in vec2 vertexTexCoord;
in vec3 vertexNormal;
in vec4 vertexColor;

uniform mat4 mvp;
uniform mat4 matNormal;

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;

uniform vec2 uv_tiling;
uniform vec2 uv_offset;

out vec2 frag_texcoord;
out vec4 frag_colour;
out vec3 frag_lighting;

void main() {
	vec3 canopy_center = vec3(0.0, 4.0, 0.0);
	vec3 canopy_normal = vertexNormal;
	vec3 offset = vertexPosition - canopy_center;

	if (dot(offset, offset) > 0.0001) {
		canopy_normal = normalize(offset);
	}

	vec3 world_normal = normalize((matNormal * vec4(canopy_normal, 0.0)).xyz);

	float sun_facing = dot(world_normal, sun_direction);
	float moon_facing = dot(world_normal, moon_direction);

	float sun_diffuse = max(sun_facing, 0.0) + 0.1 * max(-sun_facing, 0.0);
	float moon_diffuse = max(moon_facing, 0.0) + 0.1 * max(-moon_facing, 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;

	frag_lighting = ambient_light + sun_light + moon_light;
	frag_texcoord = vertexTexCoord * uv_tiling + uv_offset;
	frag_colour = vertexColor;

	gl_Position = mvp * vec4(vertexPosition, 1.0);
}