Alpha to coverage
Encyclopedia
Alpha to coverage is a multisampling
computer graphics
technique useful for situations where dense foliage or grass must be rendered in a video game.
This technique uses the alpha channel
of textures
as a coverage mask for anti-aliasing
.
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.
Multisample Anti-Aliasing
Multisample anti-aliasing is a type of anti-aliasing, a technique used in computer graphics to improve image quality.- Definition :The term generally refers to a special case of supersampling. Initial implementations of full-scene anti-aliasing worked conceptually by simply rendering a scene at a...
computer graphics
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....
technique useful for situations where dense foliage or grass must be rendered in a video game.
This technique uses the alpha channel
Alpha compositing
In computer graphics, alpha compositing is the process of combining an image with a background to create the appearance of partial or full transparency. It is often useful to render image elements in separate passes, and then combine the resulting multiple 2D images into a single, final image in a...
of textures
Texture mapping
Texture mapping is a method for adding detail, surface texture , or color to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in his Ph.D. thesis of 1974.-Texture mapping:...
as a coverage mask for anti-aliasing
Anti-aliasing
In digital signal processing, spatial anti-aliasing is the technique of minimizing the distortion artifacts known as aliasing when representing a high-resolution image at a lower resolution...
.
Alpha to coverage multisampling is based on regular multisampling, except that the alpha
Alpha compositing
In computer graphics, alpha compositing is the process of combining an image with a background to create the appearance of partial or full transparency. It is often useful to render image elements in separate passes, and then combine the resulting multiple 2D images into a single, final image in a...
coverage mask is ANDed with the multisample mask. Alpha-to-coverage converts the alpha
Alpha compositing
In computer graphics, alpha compositing is the process of combining an image with a background to create the appearance of partial or full transparency. It is often useful to render image elements in separate passes, and then combine the resulting multiple 2D images into a single, final image in a...
component output from the pixel shader to a coverage mask. When the multisampling
Multisample Anti-Aliasing
Multisample anti-aliasing is a type of anti-aliasing, a technique used in computer graphics to improve image quality.- Definition :The term generally refers to a special case of supersampling. Initial implementations of full-scene anti-aliasing worked conceptually by simply rendering a scene at a...
is applied each output fragment gets a transparency of 0 or 1 depending on alpha coverage and the multisampling
Multisample Anti-Aliasing
Multisample anti-aliasing is a type of anti-aliasing, a technique used in computer graphics to improve image quality.- Definition :The term generally refers to a special case of supersampling. Initial implementations of full-scene anti-aliasing worked conceptually by simply rendering a scene at a...
result.