Deferred Rendering

TODO: Describe deferred rendering and its advantages and disadvantages.

Using Deferred Rendering

To use deferred rendering, use the appropriate render_config by setting graphics.config to core/rendering/deferred in your project's config.ini. Also include the core/rendering/deferred package in boot.packages list and set environment.renderer to deferred.

Implementation

Yeti's deferred rendering implementation uses deferred shading rather than deferred lighting for various reasons, notably:

1. To reduce the number of scene passes and associated costs;
2. to reduce the cost of intermediary buffers; and
3. to allow for implementation of lighting and shading in compute shaders.

Geometry-buffer

The geometry-buffer is highly compressed as a memory and bandwidth optimization:

• Material diffuse and specular are YCoCg encoded and sub-sampled a la ["The Compact YCoCg Frame Buffer", Mavridis and Papaioannou 2012], with heavily optimized reconstruction by leveraging fetch4 and gather4.
• Surface normals are encoded into two components via stereographic projection a la Crysis 3.
  • We may move towards Octrahedral encoding.
• In the future, additional material parameters such as surface depth for SSS a la Frostbite 2, or material information a la Destiny, will be encoded in a global texture and looked up via ID.

Render Target	Red	Green	Blue	Alpha
Depth & Stencil	Depth	-	-	Stencil
Render Target 0	Diffuse (YCoCg)	-	Specular (YCoCg)	-
Render Target 1	Normal (Encoded)	-	Roughness	ID (Reserved)