Fix IllegalArgumentException caused by null arrays

Author: kitskub

src/main/java/org/spout/physics/engine/DynamicsWorld.java

@@ -116,15 +116,16 @@ public DynamicsWorld(Vector3 gravity, float timeStep) {
         mTimer = new Timer(timeStep);
         mGravity = gravity;
         mIsGravityEnabled = true;
-        mConstrainedLinearVelocities = null;
-        mConstrainedAngularVelocities = null;
+        Vector3[] empty = new Vector3[0];
+        mConstrainedLinearVelocities = empty;
+        mConstrainedAngularVelocities = empty;
         mContactSolver = new ContactSolver(mMapBodyToConstrainedVelocityIndex);
         mConstraintSolver = new ConstraintSolver(mConstrainedPositions, mConstrainedOrientations, mMapBodyToConstrainedVelocityIndex);
         mNbVelocitySolverIterations = ReactDefaults.DEFAULT_VELOCITY_SOLVER_NB_ITERATIONS;
         mNbPositionSolverIterations = ReactDefaults.DEFAULT_POSITION_SOLVER_NB_ITERATIONS;
         mIsSleepingEnabled = ReactDefaults.SLEEPING_ENABLED;
-        mSplitLinearVelocities = null;
-        mSplitAngularVelocities = null;
+        mSplitLinearVelocities = empty;
+        mSplitAngularVelocities = empty;
         mNbIslands = 0;
         mNbIslandsCapacity = 0;
         mIslands = null;

src/test/java/org/spout/physics/DynamicsWorldTest.java

@@ -48,6 +48,12 @@ public class DynamicsWorldTest {
     public void test() throws InterruptedException {
         final float timeStep = ReactDefaults.DEFAULT_TIMESTEP;
         final DynamicsWorld world = new DynamicsWorld(new Vector3(0, -9.81f, 0), timeStep);
+        world.setEventListener(new TestListener());
+        world.start();
+        Thread.sleep(200);
+        // We want to do one update with no bodies
+        world.update();
+        world.stop();
         final BoxShape floorShape = new BoxShape(new Vector3(10, 0.5f, 10));
         final Transform floorTransform = new Transform(new Vector3(0, 0, 0), Quaternion.identity());
         final Matrix3x3 floorInertia = new Matrix3x3();
@@ -63,7 +69,6 @@ public void test() throws InterruptedException {
         final RigidBody box = world.createRigidBody(boxTransform, boxMass, boxInertia, boxShape);
         final int stepCount = Math.round((1 / timeStep) * RUN_TIME);
         final int sleepTime = Math.round(timeStep * 1000);
-        world.setEventListener(new TestListener());
         world.start();
         for (int i = 0; i < stepCount; i++) {
             final long start = System.nanoTime();