Emission Map Guide for Artists
Emission Map Guide for Artists
Emission maps are used to describe how much bloom/glow should be emitted from parts of a sprite/texture.
Emission maps are grayscale: black means no emission for that pixel, white means full intensity emission. To start, here’s an example of a sprite with its corresponding emission map:


We don’t want the entire building sprite to be emitting bloom/glow, so we create an emission map in which everything is black except the windows of the building. The result is that only the windows will emit a glow. Most lighting effects should be achieved through programmed lighting and emission, so most art will not need lighting drawn into them.
Example table to describe the relationship between a sprite, its emission map, and the emitted bloom.
| 
 Sprite pixel color  | 
 Emission map pixel color  | 
 Final emitted bloom  | 
| 
 White (Full intensity color)  | 
 White (Full intensity color)  | 
 White, full intensity  | 
| 
 White (Full intensity color)  | 
 Black (No intensity color)  | 
 No emission  | 
| 
 White (Full intensity color)  | 
 Grey (Half intensity color)  | 
 White, half intensity  | 
| 
 Yellow (Full intensity color)  | 
 Grey (Half intensity color)  | 
 Yellow, half intensity  | 
| 
 Yellow (Full intensity color)  | 
 Black (No intensity color)  | 
 No emission  | 
| 
 Grey (Half intensity color)  | 
 White (Full intensity color)  | 
 Grey, full intensity  |