Implement OutlineEffect

[vanruesc]

Description

Implement an OutlineEffect.

This effect should focus on highlighting selected objects with outlines.

References:

• https://ameye.dev/notes/rendering-outlines/
• https://threejs.org/examples/?q=outline#webgl_postprocessing_outline

Tasks

• Implement OutlineMaterial.
• Create OutlineEffect.
• Create outline demo under utilities.
• Add unit test.

Implementation Details

• Use G-Buffer components (depth, object-id / selection (?))
• Reuse code from the v6 implementation if applicable
• Use Selection to manage selected objects
  • Implement a way to mark objects as selected to render selection data to G-Buffer (?)
• Per-object opacity for OutlineEffect #352
• See outline effect through transparent objects #320