Speedups by freezing nodes

hi there,

i want to load a lot of unchanging objects, or create them on the fly, eg. models like spaceships. i just want to move, rotate and scale them once they are in memory.

so i checked for display list support - jme does no use display lists (only in LWJGLFont). any special reason for this? anything faster in it that i missed?

however, the following code snippet (subclass of LoaderNode) boosts my app from 100fps to almost 400fps:

   boolean needsCompile = false;

   int displayList = 0;

   public void freeze() {
      needsCompile = true;

   public void draw(Renderer r) {

      if (displayList != 0 && !needsCompile) {
      } else {
         if (needsCompile) {
            if (displayList != 0)
               GL11.glDeleteLists(displayList, 1);
            displayList = GL11.glGenLists(1);
            GL11.glNewList(displayList, GL11.GL_COMPILE_AND_EXECUTE);

         Spatial child = null;
         for (int i = 0, cSize = children.size(); i < cSize; i++) {
            child = (Spatial) children.get(i);
            if (child != null)
         if (needsCompile) {
            needsCompile = false;

this code has some problems, which i did not solve in the hour i played with it. some of my textures are missing. but this might be handable by someone who knows a bit more of the jme system. if i don't push the attributes i destroy the textures of the font... looks like something does not clean up its state after rendering. maybe it's just my mac ;)

my code depends on LWJGL and therefore is not portable. but it should be easy to extract an interface for freezing:
public void freeze() // to tell the node to freeze before draw
public void beginFreeze() // to call newList
public void endFreeze() // to call endList
public void drawFrozen() // to execute the list
public void melt() // to destroy the list

how about this? anyone likes it?

another question:
can i reuse a loaded model a 100 times? right now i load my model into a new node for every ship. i'd like to just have the ship in memory once and reuse the geometry/LoaderNode at a 100 places. is that possible?

Jme has a clone feature for this purpose. Take a look at CloneCreator.

thanks for the clone-pointer.

but the cloning just copies the structure. so it increases mem-need.

any chance to reuse a model some hundred times without creating copies?

and are there any ideas about the freezing feature?

i really would like to have that speedup in my apps.

The clone creator can be used to copy some of the data and keep other data the same.