I need to listen for ghost body collisions.
I flip through Minie API Class CollisionSpace appears to be used to detect collisions.
If I’m wrong about CollisionSpace Please tell me which class detects ghost body collision.
If I am correct, please tell me how to use CollisionSpace. I can’t find a way to use CollisionSpace in the source code
There are 2 ways to use CollisionSpace:
PhysicsSpace using BulletAppState in the usual manner. PhysicsSpace is a subclass of CollisionSpace; it exposes the entire CollisionSpace API.For real-time, physics-oriented games, I recommend #2.
To associate application-specific information with a PhysicsGhostObject, you could use the setApplicationData() method. However, I believe this is rarely done because most people create a GhostControl.
If you use a GhostControl, it already has a reference to the model, which you can access using getSpatial(). Hence:
GhostControl gc = (GhostControl) collisionObject;
Spatial spatial = gc.getSpatial();
Thank you for your reply.
Dig deeper into the documentation I found Physics Collision Listener This is what I want 
I noticed that the Physics Collision Listener for the Minie seems to be different from the one for the bullet
Minie Specifies whether the demo that uses ContactListener and PhysicsCollisionListener exists
（The translator I’m using seems to have trouble translating statements into tense）
(If you have any questions about my question, please point them out)
On ghost objects, you can also use getOverlappingObjects() to retrieve a list of objects that currently are overlapping with ghost.
See this example:
First of all, thank you
if(ghostControl.getOverlappingObjects()!=null){
for(int i=0;i<ghostControl.getOverlappingObjects().size();i++){
if(ghostControl.getOverlappingObjects().get(i).equals(DummyRole.ghostControl)){
System.err.println("Collision detected");
}
}
}
I wrote down a basic collision call logically but I found that they would trigger many times and I only had to decide to trigger once
This code is run in update ()
Another question is how do I get the detailed coordinates of the collision where I might need to show the attack trace where it was hit
Then use the PhysicsCollisionListener.
Also, note this:
You can get that info from PhysicsCollisionEvent
I don’t understand what you mean
But I tried PhysicsCollisionListener The following problems are found
public void enableGhostCollision(){
SkinningControl modelSkinningControl = ((Node)modelSyana.model).getChild(0).getControl(SkinningControl.class);
modelSkinningControl.getAttachmentsNode("Bone023").addControl(ghostControl);
modelSyana.bulletAppState.getPhysicsSpace().add(modelSyana.ghostControl);
modelSyana.bulletAppState.getPhysicsSpace().addCollisionListener(this);
}
public void disableGhostCollision(){
SkinningControl modelSkinningControl = ((Node)modelSyana.model).getChild(0).getControl(SkinningControl.class);
modelSkinningControl.getAttachmentsNode("Bone023").removeControl(ghostControl);
modelSyana.bulletAppState.getPhysicsSpace().removeCollisionListener(this);
modelSyana.bulletAppState.getPhysicsSpace().remove(modelSyana.ghostControl);
}
@Override
public void collision(PhysicsCollisionEvent event) {
System.err.println(event.getNodeA()+","+"A");
System.err.println(event.getNodeB()+","+"B");
//throw new UnsupportedOperationException("Not supported yet."); // Generated from nbfs://nbhost/SystemFileSystem/Templates/Classes/Code/GeneratedMethodBody
}
If I attack from the same distance, I get different results
As you can see from the picture, I attacked the two collisions and the results were different Sometimes multiple results are returned and sometimes one is returned.
When I slow down the animation it becomes much normal.（Is this normal?）
Try enabling Continuous collision detection for ghost and see if it fix:
ghostControl.setCcdMotionThreshold(0.01f);
More info: An introduction to rigid-body physics :: The Minie project
void
You can see it in the video I made 10 attacks hit the 7
sometimes hit the 3 to 5
The result is far from the expected hit 
@Override
public void collision(PhysicsCollisionEvent event) {
if ( event.getNodeA().getName().equals("NodeDummy")&& event.getNodeB().getName().equals("Bone023_attachnode")) {
System.err.println("collision");collision++;
} else if ( event.getNodeA().getName().equals("Bone023_attachnode")&& event.getNodeB().getName().equals("NodeDummy")) {
System.err.println("collision");collision++;
}
}
public void enableGhostCollision(){
SkinningControl modelSkinningControl = ((Node)modelSyana.model).getChild(0).getControl(SkinningControl.class);
modelSkinningControl.getAttachmentsNode("Bone023").addControl(ghostControl);
ghostControl.setCcdMotionThreshold(0.01f);
modelSyana.bulletAppState.getPhysicsSpace().add(modelSyana.ghostControl);
//modelSyana.bulletAppState.getPhysicsSpace().addCollisionListener(this);
}
This is code that detects collisions .
My examination seems to have found nothing wrong.
I guess it was the physics engine but I don’t know if it was my misunderstanding of the physics engine or the physics engine itself
Not sure why it can not detect all hits. Maybe @sgold has an idea.
Try to call enableGhostCollision in your animation a few seconds earlier and see if it makes any difference.
In regards to this question:
You can solve this by keeping a list to track the people that have already been hit by a swing attack so that damage will only happen on the very first collision.
Whenever a hit is detected, check to see if the person is already stored in the list.
If they are not already contained in the list, do damage and add them to the list so they won’t be damaged again on the next collision.
Here’s some simplified example code to explain better:
public ArrayList<Agent> damagedAgents = new ArrayList();
public void collisionHappened(Agent collidedAgent){
if(!damagedAgents .contains(collidedAgent)){
collidedAgent.takeDamage(damage);
damagedAgents .add(collidedAgent);
}
}
And then you would also need to clear the old list at the start of each new swing motion to allow previously damaged people to be damaged again.
Also, noticed the target collider is half in the ground. Move it up and try again.
Thanks for your help I will try 
hello,sgold,
Could you give me some suggestions 
But in the relative limit distance sometimes you collide and sometimes you don't
ghostControl.setCcdMotionThreshold(0.000000000001f);
I didn’t realize that setting parameters like this would work.
That’s a lot of zeros 
Thank you very much for your help 
Continuous collision detection is only for rigid bodies. It shouldn’t have any effect on a GhostControl.
Use a sweep test instead of a GhostControl.
I guess I misunderstood again
Maybe it’s the adjustment of other parameters
I’ll run some tests.
I’ll check out the documentation on Sweep Test
Thanks for the tip