| 摘要 |
A graphic processing system for representing three-dimensional objects on a monitor which uses a pipeline of polygon processors coupled in series. The three-dimensional objects are converted into a group of two-dimensional polygons. These polygons are then sorted to put them in scan line order, with each polygon having its position determined by the first scan line on which it appears. Before each scan line is processed, the descriptions of the polygons beginning on that scan line are sent into a pipeline of polygon processors. Each polygon processor accepts one of the polygon descriptions and stores it for comparison to the pixels of that scan line which are subsequently sent along the polygon processor pipeline. For each new scan line, polygons which are no longer covered are eliminated and new polygons are entered into the pipe. After each scan line is processed, the pixels can be sent directly to the CRT or can be stored in a frame buffer for later accessing. Two polygon processor pipelines can be arranged in parallel to process two halves of a display screen, with one pipeline being loaded while the other is processing. A frame buffer and frame buffer controller are provided for overflow conditions where two passes through the polygon pipeline are needed. A unique clipping algorithm forms a guardband space around a viewing space and clips only polygons intersecting both shells. Extra areas processed are simply not displayed.
|
