Mesh selection with Z-fighting geometry incorrect when Settings > Antialiasing enabled.

[hexabits]

Color picking needs to be rewritten to bypass the sample buffer when multisampling is enabled. It currently uses the backbuffer, which uses the sample buffer just like the front buffer.

This happened in previous versions, though it was harder to notice. AFAICT the Antialiasing option didn't actually do anything.

Tracking

#56 OpenGL Refactoring

[hexabits]

For posterity:

Example of what it should look like (multisampling disabled):

and what it looked like when Settings > Antialiasing was enabled:

If you look closely, the Z-fighting geometry gets dithered, or blurred, together. This creates gradations in the color values which will invariably lead to incorrect or invalid block indices being selected.

Solution was using an FBO to render the color key to, which has a separate format from the main rendering context.