Ich programmiere gerade mit Java ein Plugin für einen Sponge Minecraft Server, und möchte es dem Assassinen ermöglichen, anderen in den Rücken zu stechen. Dazu mus ich feststellen, ob beim Damage Event der Schadensverursacher hinter der anderen Person steht. Wie mache ich das am besten? Ich habe die beiden Richtungen der Spieler als vector3d Variable, weiß aber nicht wie ich das machen soll, da ich nicht weiß wie man mit 3D Vektoren rechnet.

Code bist jetzt:

Player atk = p; Entity victim = p2; Vector3d position = atk.getRotation(); Vector3d location = victim.getRotation();

package pack2;

import java.awt.Graphics;

import javax.swing.ImageIcon;

public class GeometricImage extends GeometricObjekt implements Printable{

ImageIcon icon;

public GeometricImage(String fileName,int x,int y) {
    super(new Vertex(x,y));
    icon = new ImageIcon(getClass().getClassLoader().getResource(fileName));
    init();
    }
public GeometricImage(ImageIcon icon,int x,int y){
    super(new Vertex(x,y));
    this.icon =icon;
    init();
}

void init(){
    width = icon.getImage().getWidth(icon.getImageObserver());
    height = icon.getImage().getHeight(icon.getImageObserver());
}

public void paintTo(Graphics g) {
    icon.paintIcon(null, g, pos.x, pos.y);      
}

public static void main(String[] args){
    GeometricImage gi = new GeometricImage("rocket.png",10,10);
    System.out.println(gi.width);
    System.out.println(gi.height);
    ShowInFrame.show(new PrintablePanel(gi));
}

}

package pack2;

public class PrintablePanel extends SizedPanel{ private static final long serialVersionUID = 1L; Printable pa; public PrintablePanel(Printable pa) { this.pa = pa; }

@Override
public void paintComponent(java.awt.Graphics g){
    pa.paintTo(g);
}

}

er beschwert sich immer bei den Zeilen icon.paintIcon(null, g, pos.x, pos.y); und pa.paintTo(g); und Printable is n Interface das paintTo hinzufügt falls noch was unverstädlich is einfach fragen

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExceptionat pack2.GeometricImage.paintTo(GeometricImage.java:28)at pack2.PrintablePanel.paintComponent(PrintablePanel.java:12)at javax.swing.JComponent.paint(Unknown Source)at javax.swing.JComponent.paintChildren(Unknown Source)at javax.swing.JComponent.paint(Unknown Source)at javax.swing.JComponent.paintChildren(Unknown Source)at javax.swing.JComponent.paint(Unknown Source)at javax.swing.JLayeredPane.paint(Unknown Source)at javax.swing.JComponent.paintChildren(Unknown Source)at javax.swing.JComponent.paintToOffscreen(Unknown Source)at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)at javax.swing.RepaintManager.paint(Unknown Source)at javax.swing.JComponent.paint(Unknown Source)at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)at java.awt.Container.paint(Unknown Source)at java.awt.Window.paint(Unknown Source)at javax.swing.RepaintManager$4.run(Unknown Source)at javax.swing.RepaintManager$4.run(Unknown Source)at java.security.AccessController.doPrivileged(Native Method)at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)at javax.swing.RepaintManager.access$1200(Unknown Source)at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)at ......