METHOD AND APPARATUS FOR SIMULTANEOUSLY RENDERING MULTIPLE SCANLINES

A method and apparatus for simultaneously rendering multiple scanlines. Using a scanline approach to rendering, multiple scanlines may be rendered simultaneously through the use of parallel rendering means. The rendering of multiple scanlines in parallel is enabled by creating scanline independence. Scanline independence is achieved by interpolation through direct evaluation of object information. During the rendering process each of the rendering means vertically interpolates to identify a span corresponding to the scanline being rendered. A span is identified by it's X, Y coordinates on a scanline. The scanline being rendered provides the Y-coordinate. Vertical interpolation generally involves the step of deriving the X-coordinates for the endpoints of the span and comprises the steps of: identifying active edges of the object, calculating a relative interpolation weight for each active edge and solving a linear interpolation function using the relative interpolation weight and the leftmost X-coordinate of the active edges and the rightmost X-coordinate of the active edges.