How to handle multiple "Scenes" - Wiki Improvement

[duysqubix]

Loving the library. I made a shift from Godot to this for the simple reason that learning 2+ more languages (gdscript, godot's glsl-esque shading language) and/or using their compiled implementations ended up slowing development down, and causing more headaches than it solved.

With that said, one area that I am failing to see much documentation on, which I think is a pretty fundamental concept in game design is handling "scene" switching, though pixel tries not to be heavy handed in implementation approach, A simple pattern for these basic operations may not be a bad thing.

Original issue: faiface/pixel#209