#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;
out vec3 frag_normal;

in vec4 vertexBoneIndices;
in vec4 vertexBoneWeights;

uniform mat4 boneMatrices[64];

void main() {
	mat4 skin =
		vertexBoneWeights.x * boneMatrices[int(vertexBoneIndices.x)] +
		vertexBoneWeights.y * boneMatrices[int(vertexBoneIndices.y)] +
		vertexBoneWeights.z * boneMatrices[int(vertexBoneIndices.z)] +
		vertexBoneWeights.w * boneMatrices[int(vertexBoneIndices.w)];

	vec4 position = skin * vec4(vertexPosition, 1.0);
	vec3 normal = (skin * vec4(vertexNormal, 0.0)).xyz;
	vec3 world_normal = normalize((matNormal * vec4(normal, 0.0)).xyz);

	float sun_diffuse = max(dot(world_normal, sun_direction), 0.0);
	float moon_diffuse = max(dot(world_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;

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

	gl_Position = mvp * position;
}