Contact_point_event vs. contact_point_response

totebo · September 19, 2024, 8:42pm

Following up on a Discord discussion, it looks like the position given in contact_point_event is different from that in contact_point_response:

ContactPointResponse.zip (5.0 KB)

I’d like to use physics.set_listener(), but I’m geen to get the contact point position, rather than the collision object position. Still unsure if the position given by contact_point_event is by design, or if I’m missing something?

Mathias_Westerdahl · September 20, 2024, 10:02am

Yes, in the contact_point_response, the contact point itself is the main subject:

position
world position of the contact point (vector3).

whereas the contact_point_event returns a single event, where each point is the position of each object:

position
vector3 The world position of object A

I agree that it’s not great to not report the local point of the collisions.
Please feel free to report an issue!

totebo · September 21, 2024, 7:56am

With pleasure, sir!

github.com/defold/defold

Complement contact_point_event by including the contact position

opened 07:55AM - 21 Sep 24 UTC

closed 10:12AM - 30 Sep 24 UTC

totebo

feature request engine physics good first issue quick win?

**Is your feature request related to a problem? Please describe (REQUIRED):** W…hen using `physics.set_listener()`, the `contact_point_event` doesn't return the contact position. The `contact_point_response` message does return it, but requires a .script file to be added to each game object with a collision object attached. I'd prefer to use `physics.set_listener()` as it can be more performant when using many game objects, as well as keeping all collision code in one place. **Describe the solution you'd like (REQUIRED):** The current data structure returned by `contact_point_event` looks like this: ``` { applied_impulse = n, distance = n, a = {}, b = {}, } ``` It would make sense to include the contact position, too: ``` { position = vector3, applied_impulse = number, distance = number, a = {}, b = {}, } ``` **Describe alternatives you've considered (REQUIRED):** Using the game object position, rather than the contact position.