Slick Forums

import java.util.TimerTask;

import org.newdawn.slick.Graphics;

public class DrawBox extends TimerTask{
   
   Graphics g = MainGame.graphics;
   float start = 0;
   float startY = 0;
   float end = 1;
   float endY = 1;
   long time = 0;
   
   
   public void run() {
      System.out.println(g);
      g = MainGame.graphics;
      g.drawLine(start, startY, end-((time/50)*(time/50)), startY);//top line
      g.drawLine(start, endY, end-((time/50) * (time/50)), endY);//bottom line
      g.drawLine(start, startY, start, endY-((time/50)*(time/50)));//left
      g.drawLine(end-((time/50)*(time/50)), startY, end, endY-((time/50)*(time/50)));//right
      
      
      if(time == 1000){
         this.cancel();
         return;
      }
      time += 50;
   }
   
}

Exception in thread "Timer-1" java.lang.NullPointerException
   at org.lwjgl.opengl.GL11.glDisable(GL11.java:1009)
   at org.newdawn.slick.opengl.renderer.ImmediateModeOGLRenderer.glDisable(ImmediateModeOGLRenderer.java:147)
   at org.newdawn.slick.opengl.TextureImpl.bindNone(TextureImpl.java:120)
   at org.newdawn.slick.Graphics.fillRect(Graphics.java:888)
   at org.newdawn.slick.Graphics.drawLine(Graphics.java:473)
   at DrawBox.run(DrawBox.java:18)
   at java.util.TimerThread.mainLoop(Unknown Source)
   at java.util.TimerThread.run(Unknown Source)

public void update(int delta) {
    time += delta;
    if (time > 1000) { //every 1 second
        time = 0;
        doAction();
    }
}

public void drawBox(org.newdawn.slick.Color colour, int start, int startY, int end, int endY){
//stuff
}

public class B extends BasicGame{
//whatever
public void render(GameContainer gc, Graphics g) throws SlickException{
new Player().render(gc, g);
}
}
public class Player{
public void render(GameContainer gc, Graphics g) throws SlickException{
//whatever
}
}

public float size = 10;

public void render(GameContainer c, Graphics g) throws SlickException {
    g.drawRect(50, 50, size, size);
    size += 0.5f;
}