First, to improve 2D lighting performance, try increasing the Scissor Area Threshold project setting above its default value (
Unlike 3D, there is no built-in way to bake lightmaps in 2D. There would be two ways to approach this from an editor plugin side:
- Bake a texture that is overlaid with a CanvasItemMaterial set to the Multiply Blend mode.
- Use Sprites with Add blend mode to represent light. If you don't need shadows, it's all you have to do. If you need shadows, you could have a plugin that creates Polygon2Ds depending on surrounding light occluders and renders them to a viewport which is modulated with a black transparent color.
Both of those approaches involve a significant amount of work when you need shadows.
Godot 4.0 will use a single-pass approach to 2D lighting, which is much faster when you use several lights that affect the same sprite.