package com.pandadev.eyecandy.graphics;

import org.lwjgl.util.vector.Matrix4f;
import org.lwjgl.util.vector.Vector3f;

import com.pandadev.eyecandy.MatrixStack;

public abstract class Camera {
	private final Vector3f position = new Vector3f();
	private final Vector3f target = new Vector3f(0f, 0f, -1f);
	private final Vector3f up = new Vector3f(0f, 1f, 0f);
	
	public abstract void update(float delta);
	
	public void applyTransformations(){
		Matrix4f viewMatrix = new Matrix4f();
		Vector3f zAxis = getForward();
		Vector3f xAxis = getRight();
		Vector3f yAxis = getUp();
		viewMatrix.m00 = xAxis.x;
		viewMatrix.m10 = xAxis.y;
		viewMatrix.m20 = xAxis.z;
		viewMatrix.m01 = yAxis.x;
		viewMatrix.m11 = yAxis.y;
		viewMatrix.m21 = yAxis.z;
		viewMatrix.m02 = zAxis.x;
		viewMatrix.m12 = zAxis.y;
		viewMatrix.m22 = zAxis.z;
		viewMatrix.m03 = position.x;
		viewMatrix.m13 = position.y;
		viewMatrix.m23 = position.z;
		MatrixStack.getViewMatrix().load(viewMatrix);
	}
	
	public Vector3f getForward(){
		Vector3f forward = new Vector3f();
		Vector3f.sub(position, target, forward);
		forward.normalise();
		return forward;
	}
	
	public Vector3f getBackward(){
		Vector3f backward = getForward();
		backward.negate();
		return backward;
	}
	
	public Vector3f getRight(){
		Vector3f right = new Vector3f();
		Vector3f.cross(getForward(), up, right);
		return right;
	}
	
	public Vector3f getLeft(){
		Vector3f left = getRight();
		left.negate();
		return left;
	}
	
	public Vector3f getUp(){
		Vector3f up = new Vector3f();
		Vector3f.cross(getForward(), getRight(), up);
		return up;
	}
	
	public Vector3f getDown(){
		Vector3f down = getUp();
		down.negate();
		return down;
	}
	
	public Vector3f getPosition(){
		return position;
	}
	
	public Vector3f getTarget(){
		return target;
	}
	
	public void setPosition(Vector3f position){
		this.position.set(position);
	}
	
	public void setTarget(Vector3f target){
		this.target.set(target);
	}
}