btGhostObject collides with RB's but not other btGhostObjects

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Brian Beuken
Posts: 46
Joined: Sat Jul 29, 2017 9:19 pm

btGhostObject collides with RB's but not other btGhostObjects

Post by Brian Beuken »

Hi all

I'm using a btGhostObject as well as an RB in a game object, the RB is the main physics control systems and collision, but the ghost object performs a proximity alert function; its added to the dynamic physics world as a simple collision object.Its a sphere around my object and moves with it.. it took a bit of doing to stop it colliding with its own associated RB, but I do now have a nice system where I have a variable size sphere surrounding my object (space ships) and reporting any overlapping RB from other ships to allow proximity alerts and reactions.

But.

While the Sphere->RB test is great, I really want to have a Sphere->Sphere test for a wider, less urgent prioximity alert, and I am finding that my ghost objects don't detect collisions of any kind with other ghost ojects, only RB's... can anyone tell me if there's a setting I missed when I set up my ghost objects as collision objects? You can see it in action here https://www.patreon.com/posts/hmm-good-but-hmm-53834023 I can work with this just by having a larger proximity sphere, but the 2 levels of warning are useful and I'd like to have that sphere->sphere result if possible
Brian Beuken
Posts: 46
Joined: Sat Jul 29, 2017 9:19 pm

Re: btGhostObject collides with RB's but not other btGhostObjects

Post by Brian Beuken »

I kinda worked it out..

If I made the btGhostObjects interact with each other then they'd have to react... which I don't want... so testing a non responsive sphere with a non responsive sphere does not give an actual result, which thinking about it makes sense.

So I can just make my proximity spheres a bit bigger to produce the proximity results I expect. So Ghost objects are working fine..
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