Skew transform doesn't work correctly for HeightMapShape

[kocsis1david]

Godot version

v3.4.2.stable.official [45eaa2d]

System information

Windows 10

Issue description

When skew transform is applied to a HeightMapShape, ray casting works strangely. Seems like the shape remained rectangular instead of a parallelogram.

Steps to reproduce

• Create a plane
• Add a StaticBody child with HeightMapShape collision shape, the size should be 3*3, so it matches the plane size
• Ray casting should work correctly now, because the collision shape is the same as the plane
• Change the transformation matrix to skew
• The plane render is rendered with the skew transform, but ray casting doesn't respect the skew transform

Minimal reproduction project

https://github.com/kocsis1david/godot-height-map-test

The ray intersection is printed to the console, but I get an empty result when I hover the mouse over the corner of the plane.

[Calinou]

Related to #41685. For the record, this was cross-posted on Reddit: https://www.reddit.com/r/godot/comments/s4jvi3/heightmapshape_skew/

Scaling collision shapes is not supported in Godot. It can sometimes work with uniform scaling, but it will pretty much never work reliably when using non-uniform scaling (which includes skewing).

[akien-mga]

Fixed by #77281.