jMonkeyEngine - how to get a body part which was colliding - character

Question

I am making a game in jMonkeyEngine where 2 characters fight together. I want that program to fetch information about collisions with simple body parts. Example, if I give punch for a character the program has knowledge about the body part. I know that jMonkey can give me information about skeleton, but collisions are between geometries. My idea is to create a group of the objects as a character and get geometry in jME. Is it a good idea? I create objects in Blender.

Answer 1

You can try approximate your shapes with a geometry that is simpler and use that for collisions. For a character it works for me to use a cylinder and the helper class BetterCharacterControl.
private BetterCharacterControl characterControl;
#Override
public void simpleUpdate(float tpf) {
characterControl.setGravity(planetAppState.getGravity());
// Get current forward and left vectors of model by using its rotation
// to rotate the unit vectors
Vector3f modelForwardDir = characterNode.getWorldRotation().mult(Vector3f.UNIT_Z);
Vector3f modelLeftDir = characterNode.getWorldRotation().mult(Vector3f.UNIT_X);
// WalkDirection is global!
// You *can* make your character fly with this.
walkDirection.set(0, 0, 0);
if (leftStrafe) {
walkDirection.addLocal(modelLeftDir.mult(5));
} else if (rightStrafe) {
walkDirection.addLocal(modelLeftDir.negate().multLocal(5));
}
if (forward) {
walkDirection.addLocal(modelForwardDir.mult(5));
} else if (backward) {
walkDirection.addLocal(modelForwardDir.negate().multLocal(5));
}
characterControl.setWalkDirection(walkDirection);
// ViewDirection is local to characters physics system!
// The final world rotation depends on the gravity and on the state of
// setApplyPhysicsLocal()
if (leftRotate) {
Quaternion rotateL = new Quaternion().fromAngleAxis(FastMath.PI * tpf, Vector3f.UNIT_Y);
rotateL.multLocal(viewDirection);
} else if (rightRotate) {
Quaternion rotateR = new Quaternion().fromAngleAxis(-FastMath.PI * tpf, Vector3f.UNIT_Y);
rotateR.multLocal(viewDirection);
}
characterControl.setViewDirection(viewDirection);
if (walkDirection.length() == 0) {
if (!"Idle".equals(animationChannel.getAnimationName())) {
animationChannel.setAnim("Idle", 1f);
}
} else {
if (!"Walk".equals(animationChannel.getAnimationName())) {
animationChannel.setAnim("Walk", 0.7f);
}
}
}
You can use a collisionshape
private CylinderCollisionShape shape;
And use jme3's helper classes to get the collision data
CollisionResults results = new CollisionResults();
// System.out.println("1 #Collisions between" + ufoNode.getName()
// + " and " + jumpgateSpatial.getName() + ": " + results.size());
ufoNode.collideWith((BoundingBox) jumpgateSpatial.getWorldBound(),
results);
// System.out.println("2 #Collisions between" + ufoNode.getName()
// + " and " + jumpgateSpatial.getName() + ": " + results.size());
CollisionResults results2 = new CollisionResults();
// Use the results
if (results.size() > 0 && playtime > 50000) {
System.out.println("playtime" + playtime);
System.out.println("#Collisions between" + ufoNode.getName()
+ " and " + jumpgateSpatial.getName() + ": "
+ results.size());
// how to react when a collision was detected
CollisionResult closest = results.getClosestCollision();
System.out.println("What was hit? "
+ closest.getGeometry().getName());
System.out
.println("Where was it hit? " + closest.getContactPoint());
System.out.println("Distance? " + closest.getDistance());
ufoControl
.setPhysicsLocation(jumpGateControl2.getPhysicsLocation());
System.out.println("Warped");
} else {
// how to react when no collision occured
}
if (results2.size() > 0) {
System.out.println("Number of Collisions between"
+ ufoNode.getName() + " and " + moon.getName() + ": "
+ results2.size());
// how to react when a collision was detected
CollisionResult closest2 = results2.getClosestCollision();
System.out.println("What was hit? "
+ closest2.getGeometry().getName());
System.out.println("Where was it hit? "
+ closest2.getContactPoint());
System.out.println("Distance? " + closest2.getDistance());
}