package org.jzy3d.plot3d.rendering.ordering;

import org.jzy3d.maths.Coord3d;
import org.jzy3d.plot3d.primitives.AbstractDrawable;
import org.jzy3d.plot3d.rendering.view.Camera;
import org.jzy3d.plot3d.rendering.view.View;


/** The {@link BarycentreOrderingStrategy} compare two {@link AbstractDrawable}s by computing
 * their respective distances to the {@link Camera}, which must be referenced prior to any
 * comparison.
 * 
 * @author Martin Pernollet
 */
public class BarycentreOrderingStrategy extends AbstractOrderingStrategy{
	public BarycentreOrderingStrategy(){
	    super();
	}
	
	public BarycentreOrderingStrategy(View view){
	    super();
	    this.view = view;
	}
	
    /**
     * Operation must be:
     * symetric: compare(a,b)=-compare(b,a)
     * transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0    true if all Drawables and the Camera don't change position!
     * consistency?: compare(x, y)==0  implies that sgn(compare(x, z))==sgn(compare(y, z))
     */
	@Override
    public int compare(AbstractDrawable d1, AbstractDrawable d2) {
		if(d1.equals(d2))
			return 0;
		return comparison(score(d1), score(d2));
	}
	
    @Override
    public double score(AbstractDrawable d) {
        if(view!=null)
            return camera.getDistance(d, view.getLastViewScaling());
        else
            return camera.getDistance(d);
    }
    
    @Override
    public double score(Coord3d coord) {
        if(view!=null)
            return camera.getDistance(coord, view.getLastViewScaling());
        else
            return camera.getDistance(coord);
    }
}