Alpha to coverage
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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 is a sub-pixel version of screen-door transparency, a technique which uses a dithering pattern to simulate transparency with only fully opaque and fully transparent pixels.[5]
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.
See also
[edit | edit source]References
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External links
[edit | edit source]- GPU Gems 3 ‒ Chapter 4. Next-Generation SpeedTree Rendering
- Street Fighter IV PC explained in detail
