Add a toggleable mesh origin display in the GridMap editor

[jkulawik]

Describe the project you are working on

A 3D game which features levels made using GridMap

Describe the problem or limitation you are having in your project

When using meshes which aren't entirely enclosed in the cell size (e.g. stairs, meshes with origins in their corner), deleting them on the GridMap is cumbersome. It is usually not possible to tell which cell each mesh belongs to, requiring a lot of fiddling to remove it.

This issue is exacerbated when using multiple floors on the GridMap.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

In the GridMap editor:

• Implement a toggleable display of cell origins
  • Display a dot in the cell with the mesh
  • Display the floor the cell belongs to as a number next to the dot (with a separate toggle)
  • Limit the display of the above to a configurable radius around the cursor
  • Add a similar dot display to the current cursor placement. Use a contrasting color to distinguish. This part is also particularly useful when a currently used mesh is invisible because of backface culling (e.g. painting a ceiling without flipping the camera upside down)
  • Alternatively, color the entire cell instead of using dots (this will be much easier to read, however I'm not sure if meshes are placed on line intersections or in the middle of the squares)
• Add 3D scaling for the select mode (Shift+drag)
  • After the horizontal area is selected, make the next mouse drag set the selection box height

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

These changes should be fairly simple expansions of existing code

If this enhancement will not be used often, can it be worked around with a few lines of script?

Not that I know of and seems unlikely

Is there a reason why this should be core and not an add-on in the asset library?

It's a part of an already existing core feature