Unexpected intersection values in precollision event

I apologize for the vague title, but I’m not too sure how to succinctly explain this one 😅

Below is a clip of logging ev.intersection in the precollision event for the red actor. It has a passive collider, while the green walls are fixed. It seems that when the red actor is colliding near the bottom 10% of the green actor, the intersection stops populating x and instead populates y.

(the laggy console logging is just codesandbox being slow)

https://user-images.githubusercontent.com/8703090/188290360-01a15255-5a2d-4915-84e0-66100099d322.mp4

Here’s a bit more context showing how I initially ran into this:

This is essentially a makeshift raycast. There are 8 of these “rays”, one on for each corner, doing the same precollision event checking. For debugging purposes, when any of them detect a precollision they are colored red. I then use the intersection values to determine the distance to the collision. So the horizontal colliders will use x, and vertical y. As you can see, the horizontal bottom-right corner suffers from this issue, as the x value is 0 for its intersection.

It’s possible I am abusing this intersection value for something it’s not meant to be used for. #2410 is likely going to be the better solution… but this is actually working quite well otherwise!

Is there a reason only x or y are populated, and not both? Perhaps it would be better if they were?

Steps to Reproduce

https://codesandbox.io/s/excalibur-collision-intersection-bug-x26fug?file=/index.js

Expected Result

The x value of the intersection should continue to be the populated value.

Actual Result

The x value stops being populated and instead y is.

Environment

• browsers and versions: Chrome 105
• operating system: macOS 12.5
• Excalibur versions: 0.27

[mattjennings]

@eonarheim hmm I see… I think I understand. Unfortunately the suggested workarounds aren’t going to work for me but I know I’m sort of pushing the boundaries of this approach anyway. I can wait for the raycasting and see how well that works in its place!

[eonarheim]

@mattjennings Definitely seems like a bug to me, very unexpected.

I’ll dig in and see if I can figure out what’s up.

Sorry for the rough edges in collision, but I appreciate all the fixes we’ve got into excalibur because of your efforts 👍