| 摘要 |
A texture loading pipeline loads textures for use in rendering an object. A source texture has one or more levels of detail. Each level of detail (LOD) contains texture tiles for a particular area of a global coordinate space at a particular resolution. There are no mandatory relationships between the areas represented by, or the resolutions of, different levels of detail. An instance of the texture loading pipeline exist for each LOD in the source texture. The texture tiles of an LOD are stored in a texture storage, which can be local or remote from the texture loading pipeline. An asynchronous request queue (ARQ) retrieves texture tiles in a region of interest from the texture storage and stores the tiles in a tile cache. Toroidal roaming is used to page textures in the region of interest from the tile cache to a texture cache. The toroidal roaming performs the best possible update of the texture cache given a limited update time. A pipeline driver drives the pipeline by providing the region of interest to the tile cache and the region of interest and an update time to texture cache. The majority of processing time is devoted to the highest-resolution texture loading pipeline that can keep up with the rate of change in the region of interest. After an update cycle, a texture selector selects the textures in the texture cache having the best set of textures for the region of interest and those textures are used to render the 3-D scene. |
