IViewportTransform.java

/**
 * 
 * 1:13:11 AM, Jul 17, 2009
 */
package org.jbox2d.common;

/**
 * This is the viewport transform used from drawing.
 * Use yFlip if you are drawing from the top-left corner.
 * @author daniel
 */
public interface IViewportTransform {
	
	/**
	 * @return if the transform flips the y axis
	 */
	public boolean isYFlip();

	/**
	 * @param yFlip if we flip the y axis when transforming
	 */
	public void setYFlip(boolean yFlip);
	
	/**
	 * This is the half-width and half-height.
	 * This should be the actual half-width and 
	 * half-height, not anything transformed or scaled.
	 * Not a copy.
	 * @return
	 */
	public Vec2 getExtents();
	
	/**
	 * This sets the half-width and half-height.
	 * This should be the actual half-width and 
	 * half-height, not anything transformed or scaled.
	 * @param argExtents
	 */
	public void setExtents(Vec2 argExtents);
	
	/**
	 * This sets the half-width and half-height of the
	 * viewport. This should be the actual half-width and 
	 * half-height, not anything transformed or scaled.
	 * @param argHalfWidth
	 * @param argHalfHeight
	 */
	public void setExtents(float argHalfWidth, float argHalfHeight);
	
	/**
	 * center of the viewport.  Not a copy.
	 * @return
	 */
	public Vec2 getCenter();
	
	/**
	 * sets the center of the viewport.
	 * @param argPos
	 */
	public void setCenter(Vec2 argPos);
	
	/**
	 * sets the center of the viewport.
	 * @param x
	 * @param y
	 */
	public void setCenter(float x, float y);
	
	/**
	 * Sets the transform's center to the given x and y coordinates,
	 * and using the given scale.
	 * @param x
	 * @param y
	 * @param scale
	 */
	public void setCamera(float x, float y, float scale);
	
	/**
	 * Transforms the given directional vector by the
	 * viewport transform (not positional)
	 * @param argVec
	 * @param argOut
	 */
	public void vectorTransform(Vec2 argWorld, Vec2 argScreen);
	
	
	/**
	 * Transforms the given directional screen vector back to
	 * the world direction.
	 * @param argVec
	 * @param argOut
	 */
	public void vectorInverseTransform(Vec2 argScreen, Vec2 argWorld);
	
	
	/**
	 * takes the world coordinate (argWorld) puts the corresponding
	 * screen coordinate in argScreen.  It should be safe to give the
	 * same object as both parameters.
	 * @param argWorld
	 * @param argScreen
	 */
	public void getWorldToScreen(Vec2 argWorld, Vec2 argScreen);
	
	
	/**
	 * takes the screen coordinates (argScreen) and puts the
	 * corresponding world coordinates in argWorld. It should be safe
	 * to give the same object as both parameters.
	 * @param argScreen
	 * @param argWorld
	 */
	public void getScreenToWorld(Vec2 argScreen, Vec2 argWorld);
}