Problem with platformer

tylenol

Hello,

I'm attempting to create a 2d platformer in Processing in Eclipse. I get this error and the rectangle won't move though:

Exception in thread "Animation Thread" java.lang.NullPointerException
    at processing.core.PApplet.handleDraw(PApplet.java:2337)
    at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:237)
    at processing.core.PApplet.run(PApplet.java:2177)
    at java.lang.Thread.run(Unknown Source)

If it helps here is my code:

package spacefelt.main;

import processing.core.*;

public class eqd extends PApplet {

    private static final long serialVersionUID = 1L;

PImage collideimg;
 PImage displayimg;

 float playerX = 100;
 float playerY = 100;
 float playerXvelocity = 0;
 float playerYvelocity = 0;
 float playerJumpSpeed = -2;
 float playerSpeed = 4;
 float playerSize = 10;
 float up;
 float right;
 float down;
 float left;
 boolean isonGround;
 float grvty = .3f;
 final int W = 800;
 final int H = 600;

 boolean isLTNOverlapping(float lft, float top, float rght, float btm,
         float otherlft, float othertop, float otherrght, float otherbtm) {
     return !(left > otherrght || right < otherlft || top > otherbtm || btm < othertop);
 }


 public  void setup() {
     size(W, H);
     collideimg = requestImage("C:\\Users\\abilitage\\workspace\\Spacefelt3\\imgs\\collide.png");
     displayimg = requestImage("C:\\Users\\abilitage\\workspace\\Spacefelt3\\imgs\\disp.png");
 }

 public void draw() {
     fill(0);

     playerXvelocity += grvty;
     playerXvelocity = (right - left) * playerSpeed;
     float nxtY = playerY + playerYvelocity;
     float nxtX = playerX + playerXvelocity;

     boolean templateOnGround = false;
     if(collideimg.width > 0) {
         image(collideimg, 0, 0, width, height);
     }

     if(displayimg.width > 0) {
         image(displayimg, 0, 0, width, height);
     }

     collideimg.loadPixels();

     for(int y = 0; y < collideimg.height; y += 1) {
         for(int x = 0; x < collideimg.width; x += 1) {
             int pixc = color(collideimg.pixels[y*collideimg.width+x]);
             float scaledifference = width / collideimg.width;
             float px = nxtX;
             float py = playerY;
             float platX = x * (int)scaledifference;
             float platY = y * (int)scaledifference;
             float tiles = 10;
             float playerSize = 10;
             if(isLTNOverlapping(platX, platY, platX + tiles, platY + tiles, px, py, px + playerSize, py + playerSize) && red(pixc) == 0) {
                 if(playerXvelocity < 0 && playerX >= platX + tiles) {
                     playerXvelocity = 0;
                 }

                 if (playerXvelocity > 0 && playerX < platX)
                  {
                    playerXvelocity = 0;
                  }
             }
        px = playerX;
        py = nxtY;

        if (isLTNOverlapping(platX, platY, platX + tiles, platY + tiles, px, py, px + playerSize, py + playerSize) && red(pixc) == 0)
        {
            fill(255, 0, 0);
         }

        if(playerYvelocity > 0 && playerY < platY) {
            playerYvelocity = 0;
            templateOnGround = true;
        }
     }
 }

     playerX += playerXvelocity;
     playerY += playerYvelocity;
     rect(playerX, playerY, playerSize, playerSize);
     isonGround = templateOnGround;
}

 void keyrelease() {
     if (key == CODED)
      {
        if (keyCode == LEFT)
        {
          left = 0;
        }
        if (keyCode == RIGHT)
        {
          right = 0;
        }
        if (keyCode == UP)
        {
          up = 0;
        }
        if (keyCode == DOWN)
        {
          down = 0;
        }
     }
 }

 public void keypressed()
 {
   if (key == ' ')
   {
     if (isonGround == true)
     {
       playerYvelocity = playerJumpSpeed;
     }
   }


   if (key == CODED)
   {
     if (keyCode == LEFT)
     {
       left = 1;
     }
     if (keyCode == RIGHT)
     {
       right = 1;
     }
     if (keyCode == UP)
     {
       up = 1;
     }
     if (keyCode == DOWN)
     {
       down = 1;
     }
   }
 }
}

PhiLho

Not sure why you get an exception, but with names keypressed() and keyrelease(), I don't think you will get correct keyboard handling!

koogs

does loadPixels (line 57) work with requestImage (line 36)?

what happens when the image hasn't loaded? is pixels[] empty? null?

try using loadImage() instead. i'd argue that you should use loadImage anyway as loading the two main graphics is something that should block until it's finished.

eddie

Make sure that your main class is set to visible (this.setVisible()) before running init on your PApplet sketch.