3D Graphics - Beginning J2ME: From Novice to Professional - page 298

allows a World to contain everything in a scene. The code from Listing 15-4 to load the .m3g file
is as follows:
World mWorld;
...
mWorld = (World) Loader.load("/pogoroo.m3g")[0];
Once a World is created, you can use some of its methods to obtain familiar objects. The
active Camera is obtained using this method:
Camera getActiveCamera();
The Background is obtained using this method:
Background getBackgroud();
In addition, the 3D modeling tool used to create the .m3g file will allow you to assign special
integer IDs to any Object3D subclass that you create. You can then use the find() method to
locate any object within the World :
Object3D find(int userID);
Retrieving the Active Camera in the Retained Mode World
In Listing 15-4, the Camera is retrieved from the World and moved to the front of the jumping
kangaroo. The following code from the init() method illustrates this:
mCam = mWorld.getActiveCamera();
mCam.translate(0, 0, -1.5f);
mCam.setOrientation(180, 0, 1, 0);
It is necessary to change the orientation of the Camera . Initially, the Camera is facing the
back of the kangaroo in the World defined within the .m3g file.
Rendering a Retained Mode World
Rendering a frame in retained mode is significantly simpler than in immediate mode. The code
in the rendering loop that follow is from Listing 15-4:
startTime = System.currentTimeMillis() - mWorldStartTime;
mWorld.animate((int)startTime);
mGraphics3D.bindTarget(g);
mGraphics3D.render(mWorld);
mGraphics3D.releaseTarget();
flushGraphics();
The animate() method on the World is called to animate the hopping kangaroo (using
predefined animation within the World ). The entire World is rendered using the Graphic3D 's
retained mode rendering method:
void render(World world);