Question

I’m building the basic Slick game example explained here: http://slick.cokeandcode.com/wiki/doku.php?id=01_-_a_basic_slick_game, and I’m running into some problems. Specifically, the game compiles just fine, but when I try to run it, Java complains:

Exception in thread "main" java.lang.UnsatisfiedLinkError: no lwjgl in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1856)
    at java.lang.Runtime.loadLibrary0(Runtime.java:845)
    at java.lang.System.loadLibrary(System.java:1084)
    at org.lwjgl.Sys$1.run(Sys.java:75)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.lwjgl.Sys.doLoadLibrary(Sys.java:68)
    at org.lwjgl.Sys.loadLibrary(Sys.java:84)
    at org.lwjgl.Sys.<clinit>(Sys.java:101)
    at org.lwjgl.opengl.Display.<clinit>(Display.java:128)
    at org.newdawn.slick.AppGameContainer$1.run(AppGameContainer.java:39)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.newdawn.slick.AppGameContainer.<clinit>(AppGameContainer.java:36)
    at SlickBasicGame.main(SlickBasicGame.java:79)

This is my source code:

import org.newdawn.slick.AppGameContainer;
import org.newdawn.slick.BasicGame;
import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.Image;
import org.newdawn.slick.Input;
import org.newdawn.slick.SlickException;

public class SlickBasicGame extends BasicGame{

    Image plane = null;
    Image land = null;
    float x = 400;
    float y = 300;
    float scale = 1;

    public SlickBasicGame()
    {
        super("Slick2D Path2Glory - SlickBasicGame");
    }

    @Override
    public void init(GameContainer gc)
            throws SlickException {
        plane = new Image("data/plane.png");
        land = new Image("data/land.jpg");
    }

    @Override
    public void update(GameContainer gc, int delta)
            throws SlickException
    {
        Input input = gc.getInput();

        if(input.isKeyDown(Input.KEY_A))
        {
            plane.rotate(-0.2f * delta);
        }

        if(input.isKeyDown(Input.KEY_D))
        {
            plane.rotate(0.2f * delta);
        }

        if(input.isKeyDown(Input.KEY_W))
        {
            float hip = 0.4f * delta;

            float rotation = plane.getRotation();

            x+= hip * Math.sin(Math.toRadians(rotation));
            y-= hip * Math.cos(Math.toRadians(rotation));
        }

        if(input.isKeyDown(Input.KEY_2))
        {
            scale += (scale >= 5.0f) ? 0 : 0.1f;
            plane.setCenterOfRotation(plane.getWidth()/2.0f*scale, plane.getHeight()/2.0f*scale);
        }
        if(input.isKeyDown(Input.KEY_1))
        {
            scale -= (scale <= 1.0f) ? 0 : 0.1f;
            plane.setCenterOfRotation(plane.getWidth()/2.0f*scale, plane.getHeight()/2.0f*scale);
        }
    }

    public void render(GameContainer gc, Graphics g)
            throws SlickException
    {
        land.draw(0, 0);

        plane.draw(x, y, scale);

    }

    public static void main(String[] args)
            throws SlickException
    {
         AppGameContainer app =
            new AppGameContainer( new SlickBasicGame() );

         app.setDisplayMode(800, 600, false);
         app.start();
    }
}

The only change I’ve made to the original (which reports the same error), was that I have removed the package declaration.

I downloaded Slick from here: http://slick.cokeandcode.com/, by clicking on the “Download Full Distribution” link, and here’s how my Slick folder looks like:

I’m compiling the game with this command:

javac -cp lib/*:. SlickBasicGame.java

And trying to run it with this one:

java -cp lib/*:. SlickBasicGame

Answer 1

Add a -Djava.library.path=path/to/dir to the commandline or as an VM option in your IDE so that lwjgl is able to find the folder containing the native files.