Arcade Physics: Phaser.GameObjects.Line Does Not Collide In Group

[andrewaustin]

Version

• Phaser Version:

3.17.0

• Operating system:

OS X

• Browser:

Firefox 67.0

Description

When adding a Phaser.GameObjects.Line to a group that you then set up a collider with this.physics.add.collider(sprite, group);, the collision does not happen correctly. Instead if you turn on arcade physics debug, you see the line bounding box is in a weird place.

Since the Line object is the correct type to add to a group, I would expect collisions to work correctly. As demonstrated in the code, a workaround is to use a Rectangle, which works correctly, so it seems like an API inconsistency.

Example Test Code

Just press the up arrow on your keyboard and see the sprite does not collide with the line but does not with the group.

https://jsfiddle.net/9wrgta0s/

[dmariaa]

Problem does not only happen when adding the line to a group, it happens trying to collide with the line directly. I haven’t had enough time to investigate it, but it seems to be a problem related to the way Line class handles it’s coordinates x, y, width, height.

[photonstorm]

If you turn on debugging in Arcade Physics it's easy to see what's going on. Line Shapes don't have any height, so they're given the default height of 64px. Where-as the Rectangle above has a height of 2. Give it a height of 0 and you'll see the same thing. In 3.5 Lines now have a default height of 1, so bodies can be created from them, but they still need offsetting manually.