| 摘要 |
A system and process is provided which enables the dynamic mapping of texture to a variety of primitives, including complex primitives such as non-uniform rational B-spline surfaces (NURBS). The object, located in modeling coordinate (MC) space is parameterized to determine the parameter coordinate (PC) space associated with the object. This step is performed for an object and is readily applied to a variety of textures and views subsequently readied. Once the parameterization process has been performed, a mapping between the PC space and texture coordinate (TC) space is generated. This mapping, referred to herein as the tau mapping correlates the (s,t) coordinates of the PC space to the (u,v) coordinates of the TC space. The object is mapped from the MC space to the display coordinate (DC) and the tau mapping is then used to map the texture map onto the selected points of the object, such as the vertices of the object. Parameter interpolation is then performed to render the pixels of the object in the display space. A color composition process is executed to combine the colors of the texture map with the pixels of the object. Furthermore, in the preferred embodiment, the granularity of the texture applied to the object can be controlled using such techniques as mip-map criteria, texture quality or, in the case of NURBS, NURBS approximation criteria.
|
