Tristan Marrec

### Tile-Based Light Culling - 2022-01-03 ###

While trying to find a job in the computer graphics industry, during a preliminary interview I was asked a question about tile-based light culling, which I knew nothing about. So I decided to look into the matter and implemented it in my own engine.

The basic idea is to start the rendering pipeline with a compute shader that determines which lights cover which areas of the screen space, divided into a 2D grid. Then, during the shading phase, only those lights likely to cover the current pixel are taken into account. This makes it possible to have much more light in a scene than with conventional rendering.

Code available on GitHub or download ZIP.

Here’s the result I obtained after a few hours of prototyping. This scene would not be at an acceptable framerate without this method.

### Tiles occupancy visualization ###

The bluer the screen space tile, the more lights it contains. Interestingly, the edges of the geometries are very blue, as they contain a large spatial zone that contains all the lights between the near and far depths of the tile.

### References ###

1. Forward vs Deferred vs Forward+ Rendering with DirectX 11 - Jeremiah. 3dgep.com/forward-plus

2. Optimizing tile-based light culling - Wicked Engine. wickedengine.net/2018/01/optimizing-tile-based-light-culling