package destr.jogl.camera;

import javax.media.opengl.GL;
import javax.media.opengl.GL2;

import destr.math.Matrix4f;
import destr.math.Vector3f;

public class PerspectiveCamera {
	
	public Matrix4f	viewport = new Matrix4f(),
					transform = new Matrix4f();
	public Vector3f	eyePosition3D	= new Vector3f(),
					center3D		= new Vector3f(),
					upVector3D		= new Vector3f(),
					
					forward			=	new Vector3f(),
					side			=	new Vector3f(),
					up				=	new Vector3f();
	
	public void viewport(float fovyInDegrees, float aspectRatio, float znear, float zfar){
		float	ymax = (float) (znear * Math.tan(fovyInDegrees * Math.PI / 360.0)),
				xmax = ymax * aspectRatio;
		
		viewport = Matrix4f.makeFrustum(-xmax, xmax, -ymax, ymax, znear, zfar);
	}
	
	public void lookAt(Vector3f eyePosition3D, Vector3f center3D, Vector3f upVector3D){
		System.out.println("lookAt:" + eyePosition3D);
		this.eyePosition3D = eyePosition3D;
		this.center3D = center3D;
		this.upVector3D = upVector3D;
		updateTransform();
	}
	
	private void updateTransform(){
		forward = center3D.clone().subtract(eyePosition3D).normalize();
		side = forward.normal(upVector3D).normalize();
		up = side.normal(forward);
			
		transform = Matrix4f.makeByCols(
			side.toArray(),
			up.toArray(),
			forward.clone().inc(-1).toArray()
		);
		
		System.out.println("t-update:" + eyePosition3D);
	}
	
	public void update(GL gl){
	
		//if(needUpdate) {
			updateTransform();
		//}
		
		Matrix4f result = viewport.multiply(transform);
		
		gl.getGL2().glLoadMatrixf(result.toArray(), 0);
		gl.getGL2().glTranslatef(-eyePosition3D.x(), -eyePosition3D.y(), -eyePosition3D.z());
	}
	
	public void moveUp(GL gl, float delta){
		GL2 gl2 = gl.getGL2();
		
		gl2.glTranslatef(0,-delta,0);
		
		eyePosition3D.x(eyePosition3D.x()+delta);
		System.out.println("move:" + eyePosition3D);
	}
}