Games Track the position of a body

[ElliotHC]

Having some real fun learning B4j.

In the Space Shooter example it creates a body. There can be multiple bodies on the screen at any one time.

I want to look at a section of the screen and identify if there is a body in that section/square. Anyone know how I might do that?

Thanks

 

[Erel]

This question is not specific to B4J. It is a XUI2D question. I've moved it to the games forum.

Check Ilan's First App Example from the examples pack.

There is a panel named PanelForTouch. When the user touches it, there is a check for nearby switches. If none are found then a new ball is created.
The relevant sub is PanelForTouch_Touch and the important code is:

Dim worldpoint As B2Vec2 = X2.ScreenPointToWorld(X, Y)
For Each TouchedBody As X2BodyWrapper In X2.GetBodiesIntersectingWithWorldPoint(worldpoint)

 

[ElliotHC]

Is there a way to debug the position of the bodies as they travel down the screen?

 

[Erel]

Sure. You can find the position of all bodies.

Add this code to the Game Tick sub:

Dim bodies As List = world.AllBodies
For Each body As B2Body In bodies
   Dim bw As X2BodyWrapper = body.Tag
   If bw.Name <> "" Then
       Log(bw.Name & ": " & bw.Body.Position)
   End If
Next

 

[ElliotHC]

Thanks Erel, I'll give it a try.

 

[ElliotHC]

I need to now the 'X' position of the lowest Power body. Do I need to post this as a separate question?

I have noticed that if there are more than 1 'power' on the screen it seems to only report the position of the newest one. I'm getting position data until the next one is generated, then I start getting position info for that one. What I am trying to do is get the X position of all the powers when they are withing a certain distance from the bottom edge of the screen.

Am I going about this the right way?

Thanks

 

[Erel]

I don't remember the id of the power bodies but you can do something like:

For Each bw As X2BodyWrapper In X2.GetBodiesWrappersByIds(Array(IdOfPowerBodyThatYouShouldFindInTiled))
 Log(bw.Body.Position.Y)
Next