Vector2 cameraOffset;

// these could probably be a constant.  
float a = arctan(1/2); 
float s = 100f; // the edge-width of one cubic cell in the world.

Vector2 World2Screen(float X, float Y, float Z)
{
   float screenX = cameraOffset.X + (X-Z)cos(a)s;
   float screenY = cameraOffset.Y + ((X+Z)sin(a)-Y)s;
   return new Vector2(screenX, screenY);
}

double oddNumber = highNumber | 1; // otherwise you might end up without negative values

TemplateSlickGame (used to create a new game project in NetBeans)
  assets
    art                          (for storing images)
      sound              (for storing sounds & music)
      effects              (currently only for storing particle effects)

  slickgametemplate
    Main (main class for the app)
    SlickGame (extends StateBasedGame)
    RBGWIntroState (extends GameState to show a splash screen)


rbgwLib (code library common to all my games)
  content
    ResourceManager          (loads and indexes art, music, particle effects, etc)
    IResourceLoader          (an interface for loading resources)
      loaders
        ImageLoader        (loads images)
        SoundLoader        (loads sounds/music)
        FontLoader        (loads Slick Font types)
        ParticleLoader        (loads particle systems)
        AnimationLoader        (loads Slick Animations)
                
  TODO: Move the rest of my crappy-hacked code into this library :)

public class ResourceManager {

   private static ResourceManager _instance = new ResourceManager();
        private static ClassLoader classLoader;

   private Map<String, Sound> soundMap;
   private Map<String, Image> imageMap;
   private Map<String, ResourceAnimationData> animationMap;
   private Map<String, String> textMap;
        private Map<String, ParticleSystem> particleMap;

   private ResourceManager() {
      soundMap = new HashMap<String, Sound>();
      imageMap = new HashMap<String, Image>();
      animationMap = new HashMap<String, ResourceAnimationData>();
      textMap = new HashMap<String, String>();
                particleMap = new HashMap<String, ParticleSystem>();

                classLoader = ClassLoader.getSystemClassLoader();

                try
                {
                    /* NTS:
                     * Modifying this class to load resources from the classPath
                     * so that it can be used within applets.
                     * 22 July 2010, Matt
                     */
                    URL url = classLoader.getResource("assets/data/resources");
                    if(url != null)
                    {
                        File f = new File(url.getPath());
                        this.loadResources(new FileInputStream(f));
                    }
                    else
                    {
                        throw new NullPointerException();
                    }
                }
                catch(SlickException e)
                {
                    e.printStackTrace();
                }
                catch(FileNotFoundException e)
                {
                    e.printStackTrace();
                }
   }

   public final static ResourceManager getInstance(){
      return _instance;
   }

   public void loadResources(InputStream is) throws SlickException {
      loadResources(is, false);
   }

   public void loadResources(InputStream is, boolean deferred) throws SlickException
        {
            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = null;
            try
            {
                docBuilder = docBuilderFactory.newDocumentBuilder();
            }
            catch (ParserConfigurationException e)
            {
                throw new SlickException("Could not load resources", e);
            }

            Document doc = null;

            try
            {
                doc = docBuilder.parse (is);
            }
            catch(SAXException e)
            {
                throw new SlickException("Could not load resources", e);
            }
            catch (IOException e)
            {
                throw new SlickException("Could not load resources", e);
            }

      // normalize text representation
            doc.getDocumentElement ().normalize ();

            NodeList listResources = doc.getElementsByTagName("resource");

            int totalResources = listResources.getLength();

            if(deferred)
            {
           LoadingList.setDeferredLoading(true);
            }


            for(int resourceIdx = 0; resourceIdx < totalResources; resourceIdx++)
            {

           Node resourceNode = listResources.item(resourceIdx);

           if(resourceNode.getNodeType() == Node.ELEMENT_NODE){
                    Element resourceElement = (Element)resourceNode;

                    String type = resourceElement.getAttribute("type");

                    if(type.equals("image")){
                            addElementAsImage(resourceElement);
                    }else if(type.equals("sound")){
                            //addElementAsSound(resourceElement);
                    }else if(type.equals("text")){
                            //addElementAsText(resourceElement);
                    }else if(type.equals("font")){

                    }else if(type.equals("animation")){
                           // addElementAsAnimation(resourceElement);
                    }
                    else if(type.equals("particleSystem")){
                            addElementAsParticleSystem(resourceElement);
                    }
           }
            }
   }

       ... loads of methods for getting the files from the XML nodes ...

                     /* NTS:
                     * Modifying this class to load resources from the classPath
                     * so that it can be used within applets.
                     * 22 July 2010, Matt
                     */
                    URL url = classLoader.getResource("assets/data/resources.xml");
                    if(url != null)
                    {
                        File f = new File(url.getPath());
                        this.loadResources(new FileInputStream(f));
                    } 
                    else
                    {
                        throw new NullPointerException();
                    }

Exception in thread "Thread-14" java.lang.ExceptionInInitializerError
   at DecoGame_NixieClock.NixieClockGame.init(NixieClockGame.java:43)
   at org.newdawn.slick.AppletGameContainer$Container.initApplet(AppletGameContainer.java:272)
   at org.newdawn.slick.AppletGameContainer$ContainerPanel.initGL(AppletGameContainer.java:229)
   at org.newdawn.slick.AppletGameContainer$ContainerPanel.start(AppletGameContainer.java:216)
   at org.newdawn.slick.AppletGameContainer$1.run(AppletGameContainer.java:92)
Caused by: java.security.AccessControlException: access denied (java.io.FilePermission data\resources.xml read)
   at java.security.AccessControlContext.checkPermission(Unknown Source)
   at java.security.AccessController.checkPermission(Unknown Source)
   at java.lang.SecurityManager.checkPermission(Unknown Source)
   at java.lang.SecurityManager.checkRead(Unknown Source)
   at java.io.FileInputStream.<init>(Unknown Source)
   at Content.ResourceManager.<init>(ResourceManager.java:50)
   at Content.ResourceManager.<clinit>(ResourceManager.java:33)
   ... 5 more

<?xml version="1.0" encoding="UTF-8"?>
<resources>
<!-- GAMEPLAY -->

  <!-- GUI -->
  <resource type="image" id="IMAGE_1">art\image1.png</resource>
  <resource type="image" id="IMAGE_2">art\image2.png</resource>
  <resource type="image" id="IMAGE_3">art\image3.png</resource>

</resources>