Make engine debug draw match the editor

[subsoap]

Editor's debug draw for collision shapes is much better

Editor uses outline with less drawn solid makes stuff easier to see Editor uses a different color for different groups

[mathiaswking]

Rendering groups in separate colors is a good idea.

You can set the "less drawn solid" by setting physics..debug_alpha in the preferences. (And yes, we can move it down from 0.9 as default to what the editor uses (does it use that variable though? @matgis-king )

[matgis-king]

The editor uses a hardcoded alpha of 0.1 for the solids, increased to 0.3 when selected.

[mathiaswking]

Ok, so: Engine:

• Set better default for physics_debug_alpha
• Create different colors for each collision group

Editor:

• Use physics.debug_alpha for rendering physics shapes

[matgis-king]

I'd prefer not to respect the debug_alpha setting in the editor. Might be difficult for the editor to use a user-specified setting for this since the alpha is augmented during selection.

[subsoap]

Could the solid border be added too? That looks better in the editor as well. 😊

[mathiaswking]

@matgis-king perhaps not a crucial feature to support physics-debug_alpha in the editor, but I think it's fairly common to allow users to tweak their colors and alpha settings?