Alpha to coverage

Alpha to coverage 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.
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.
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.