Alpha to coverage

Multisampling computer graphics technique

Alpha to coverage^[1]^[2]^[3] is a multisampling computer graphics technique, that replaces alpha blending with a coverage mask. This achieves order-independent transparency for when anti-aliasing or semi-transparent textures are used. This particular technique is useful for situations where dense foliage or grass must be rendered in a video game.^[4]

Alpha to coverage multisampling is based on regular multisampling, except that the alpha coverage mask is ANDed with the multisample mask. Alpha-to-coverage converts the alpha component output from the pixel shader to a coverage mask. When the multisampling is applied each output fragment gets a transparency of 0 or 1 depending on alpha coverage and the multisampling result.

References

^ "Anti-aliased Alpha Test: The Esoteric Alpha To Coverage | by Ben Golus | Medium". 21 October 2021.
^ "Alpha to coverage | Semantic Scholar".
^ "Common Rendering Mistakes: How to Find Them and How to Fix Them | Oculus".
^ "Configuring Blending Functionality (Windows)". Microsoft Developer Network. Retrieved 2013-01-27. Alpha-to-coverage is a multisampling technique that is most useful for situations such as dense foliage where there are several overlapping polygons that use alpha transparency to define edges within the surface