Physics with Bullet - jMonkeyEngine 3.0 - page 437

How to do it...
Based on the first rule, we'll start by defining a new Control class for our networked
physics objects:
1. We create a new class called PhysicsObjectControl that extends Ab-
stractControl .
2. It should have two fields: a Boolean field called serverControlled and an in-
teger field called id .
We now define a network message to handle updates to objects with physics:
1. Let's call it PhysicsObjectMessage and have it extend AbstractMes-
sage .
2. There are three mandatory fields for it; they are as follows:
◦ The first is an integer field called objectId
◦ It also needs a Vector3f field called translation
◦ Finally, we add a Quaternion field called rotation
3. Don't forget to add the @Serializable annotation, and add it to the list of mes-
sages in the GameUtil class!
4. The last common implementation we do is for the Game class where we add a list
of Spatials called physicsObjects ; the following code tells us how to do
this:
private Map<Integer, Spatial> physicsObjects = new
HashMap<Integer, Spatial>();
Now, we can dig into the server-side implementation by performing the following steps:
1. We contain most of the code in a new AppState class called ServerPhysic-
sAppState . This AppState class will contain the reference to the Bul-
letAppState class, and it will handle the initialization.
2. Inside its initialize method, it should add the loaded level to physic-
sSpace as follows:
bulletAppState.getPhysicsSpace().add(server.getLevelNode().getChild("terrain-TestScene").getControl(PhysicsControl.class));