| 摘要 |
In a graphics processing system, the left, right, top and bottom edge planes for the purposes of clipping are set to the maximum values that can be represented using floating-point format numbers, vertex positions are snapped to a grid of predefined vertex positions, and the precision of selected vertices is prioritised when deriving edge functions for a given primitive. In respect of the depth near and far clipping planes, those planes are set to the maximum floating-point number format that can be represented for Z in the graphics system, but then fragments that have a Z value that falls outside the range zero to one are discarded by means of a depth test. In respect of the eye-plane, the need for clipping is avoided by instead modifying the edge equations generated for a primitive in dependence on the sign of the W value for each vertex of the primitive.
|
