Normal Maps for 2D Textures

[DispairingGoose]

What problem does this solve or what need does it fill?

Lighting in 2D games is often very flat.

What solution would you like?

Adding normal maps to 2d sprites

What alternative(s) have you considered?

• Baking lighting into sprite itself in an external editor - has the downside that lights cannot move

Additional context

Other Engine Implmentations:

• Godot
• Unity

[alice-i-cecile]

My understanding is that MaterialMesh2d is the intended path for these more complex use cases. Sprite should be kept very light and fast for the "just render my pixels" users. What does Bevy's existing 2D lighting ecosystem do?

I do think we should ship 2D lighting, and normal maps for 2D textures are an excellent and standard technique.

[zaycev]

@DispairingGoose there is no built-in support, but as @alice-i-cecile mentioned you can use MaterialMesh2d with few modifications. Essentially all you need to do is add atlas info into the material – texture handle and list of rectangle infos. After that you can pass your current atlas rectangle id into MaterialMesh2d shader and then sample corresponding pixel data inside of your shader. Based on how lighting / shading works in your game you should be able to use normal maps in MaterialMesh2d without any problems. This is what I was experimenting with in BML2D, but I haven't open source that part yet.