Texture atlas
Encyclopedia
In realtime computer graphics
, a texture atlas is a large image, or "atlas
" which contains many smaller sub-images, each of which is a texture for some part of a 3D object. The sub-textures can be rendered by modifying the texture coordinates of the object's uvmap
on the atlas, essentially telling it which part of the image its texture is in. In an application
where many small textures are used frequently, it is often more efficient to store the textures in a texture atlas which is treated as a single unit by the graphics hardware
. In particular, because there are less rendering state changes by binding once, it can be faster to bind one large texture once than to bind many smaller textures as they are drawn.
For example, a tile-based game
would benefit greatly in performance from a texture atlas.
Atlases can consist of uniformly-sized sub-textures, or they can consist of textures of varying sizes (usually restricted to powers of two). In the latter case, the program must usually arrange the textures in an efficient manner before sending the textures to hardware. Manual arrangement of texture atlases is possible, and sometimes preferable, but can be tedious.
If using mipmaps
, care must be taken to arrange the textures in such a manner as to avoid sub-images being "polluted" by their neighbours.
3D computer graphics
3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...
, a texture atlas is a large image, or "atlas
Atlas
An atlas is a collection of maps; it is typically a map of Earth or a region of Earth, but there are atlases of the other planets in the Solar System. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats...
" which contains many smaller sub-images, each of which is a texture for some part of a 3D object. The sub-textures can be rendered by modifying the texture coordinates of the object's uvmap
UV mapping
UV mapping is the 3D modeling process of making a 2D image representation of a 3D model.-UV mapping:This process projects a texture map onto a 3D object...
on the atlas, essentially telling it which part of the image its texture is in. In an application
Application software
Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...
where many small textures are used frequently, it is often more efficient to store the textures in a texture atlas which is treated as a single unit by the graphics hardware
Graphics processing unit
A graphics processing unit or GPU is a specialized circuit designed to rapidly manipulate and alter memory in such a way so as to accelerate the building of images in a frame buffer intended for output to a display...
. In particular, because there are less rendering state changes by binding once, it can be faster to bind one large texture once than to bind many smaller textures as they are drawn.
For example, a tile-based game
Tile-based video game
A tile-based video game is a type of video or computer game where the playing area consists of small rectangular, square, or hexagonal graphic images, referred to as tiles. The complete set of tiles available for use in a playing area is called a tileset...
would benefit greatly in performance from a texture atlas.
Atlases can consist of uniformly-sized sub-textures, or they can consist of textures of varying sizes (usually restricted to powers of two). In the latter case, the program must usually arrange the textures in an efficient manner before sending the textures to hardware. Manual arrangement of texture atlases is possible, and sometimes preferable, but can be tedious.
If using mipmaps
Mipmap
In 3D computer graphics texture filtering, MIP maps are pre-calculated, optimized collections of images that accompany a main texture, intended to increase rendering speed and reduce aliasing artifacts. They are widely used in 3D computer games, flight simulators and other 3D imaging systems. The...
, care must be taken to arrange the textures in such a manner as to avoid sub-images being "polluted" by their neighbours.
External links
- Texture Atlas Whitepaper - A whitepaper by NVIDIANVIDIANvidia is an American global technology company based in Santa Clara, California. Nvidia is best known for its graphics processors . Nvidia and chief rival AMD Graphics Techonologies have dominated the high performance GPU market, pushing other manufacturers to smaller, niche roles...
which explains the technique. - Texture Atlas Tools - Tools to create texture atlases semi-manually.
- Practical Texture Atlases - A guide on using a texture atlas (and the pros and cons).