Breakout Aufgabe 1.4

src/break_out/model/Ball.java

@@ -27,6 +27,7 @@ public class Ball implements IBall{
 	public Ball() {
 		this.position = new Position(0, 0);
 		this.direction = new Vector2D(Constants.BALL_SPEED,Constants.BALL_SPEED);
+		this.direction.rescale();
 
 		// start at bottom-center
         this.position.setX(Constants.SCREEN_WIDTH/2);

src/break_out/model/IVector2D.java

@@ -0,0 +1,12 @@
+package break_out.model;
+
+public interface IVector2D {
+
+    // Exercise 1
+    public double getDx();
+    public void setDx(double dx);
+    public double getDy();
+    public void setDy(double dy);
+
+    public void rescale();
+}

src/break_out/model/Vector2D.java

@@ -8,7 +8,7 @@ import break_out.model.Position;
  * 
  * @author I. Schumacher
  */
-public class Vector2D {
+public class Vector2D implements IVector2D {
 
 	/**
 	 * The x part of the vector
@@ -67,4 +67,13 @@ public class Vector2D {
 		this.dy = dy;
 	}
 
+	/*
+	 * Rescale part
+	 */
+	public void rescale() {
+		// calc unit vector
+		double vectorlength = Math.sqrt(Math.pow(getDx(), 2) + Math.pow(getDy(), 2));
+		setDx((1/vectorlength) * getDx() * Constants.BALL_SPEED);
+		setDy((1/vectorlength) * getDy() * Constants.BALL_SPEED);
+	}
 }