package chess.view.DDDrender.shader;

import org.joml.Matrix4f;
import org.joml.Vector3f;

import chess.view.DDDrender.Camera;

public class PieceShader extends ShaderProgram {

	private static String vertexShader = """
			#version 330

			layout(location = 0) in vec3 position;
			layout(location = 1) in vec2 uv;
			layout(location = 2) in vec3 normal;

			uniform mat4 projectionMatrix;
			uniform mat4 viewMatrix;
			uniform mat4 modelTransform;
			uniform vec3 lightPosition = vec3(0, 1, 0);

			out vec3 toLightVector;
			out vec3 surfaceNormal;

			void main(void){
				vec4 worldPos = modelTransform * vec4(position, 1.0);

				toLightVector = lightPosition - worldPos.xyz;
				surfaceNormal = (modelTransform * vec4(normal, 0.0)).xyz;

				gl_Position = projectionMatrix * viewMatrix * worldPos;
			}
				""";

	private static String fragmentShader = """
			#version 330

			in vec3 toLightVector;
			in vec3 surfaceNormal;

			uniform vec3 modelColor = vec3(1, 1, 1);

			out vec4 out_color;

			void main(void){
				vec3 unitNormal = normalize(surfaceNormal);
				vec3 unitLightVector = normalize(toLightVector);

				float diffuse = max(0.5, dot(unitNormal, unitLightVector));

				float brightness = diffuse;

				out_color = vec4(modelColor, 1.0) * brightness;
				out_color.w = 1.0;

			}
				""";

	private int location_ProjectionMatrix = 0;
	private int location_ViewMatrix = 0;
	private int location_ModelTransform = 0;
	private int location_ModelColor = 0;

	public PieceShader() {

	}

	public void LoadShader() {
		super.LoadProgram(vertexShader, fragmentShader);
	}

	@Override
	protected void GetAllUniformLocation() {
		location_ProjectionMatrix = GetUniformLocation("projectionMatrix");
		location_ViewMatrix = GetUniformLocation("viewMatrix");
		location_ModelTransform = GetUniformLocation("modelTransform");
		location_ModelColor = GetUniformLocation("modelColor");
	}

	public void SetCamMatrix(Camera camera) {
		LoadMat4(location_ProjectionMatrix, camera.getPerspectiveMatrix());
		LoadMat4(location_ViewMatrix, camera.getViewMatrix());
	}

	public void setModelTransform(Matrix4f mat) {
		LoadMat4(location_ModelTransform, mat);
	}

	public void setModelColor(Vector3f color) {
		LoadVector(location_ModelColor, color);
	}
}