Abstract: A method and apparatus for generation of pixel lookahead information in a cached computer graphics system is provided. For each pixel-based memory operation, several data items may be generated, such as numerical values representing a coordinate point in an image coordinate space or display coordinate space and characteristic data representing a color value or depth value for the pixel. In addition, lookahead data correlated with the coordinate data is generated. The pixel operation is then issued with the characteristic data, the coordinate data, and the lookahead data. The lookahead data may contain a lookahead vector, which specifies a lookahead vector direction and a lookahead vector length, and a lookahead valid flag, which indicates whether associated lookahead data is valid for the pixel operation.

Abstract: A method for verifying information comprises collecting information to be verified from a plurality of different sources wherein at least two of the sources provide information in formats which differ from one another, modifying the collected information to conform to a common format, storing the modified information in a common data base, and providing the stored information.

Abstract: A method and system for an approximation of a filter function for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels is provided. A filter response curve adjustment value is obtained, preferably from a lookup table, based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel. A normalized filter response curve input value is computed based on the distance interval and the filter response curve adjustment value, preferably by adding the values together. The characteristic values at a plurality of input pixels are obtained. A linearly interpolated value for the characteristic value of the output pixel is then computed based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value.

Abstract: A cache replacement algorithm improves upon a least recently used algorithm by differentiating between cache lines that have been written with those that have not been written. The replacement algorithm attempts to replace cache lines that have been previously written back to memory, and if there are no written cache lines available, then the algorithm attempts to replace cache lines that are currently on page and on bank.

Abstract: To reduce the performance penalty associated with frame buffer memory access times for each page when rendering a primitive having scan lines which cross page boundaries, rendering is constrained to a single page at a time. All pixels mapping to a currently-cached frame buffer page are rendered before loading a different frame buffer page into the cache in order to render other pixels within the primitive. Any pixels within a scan region which map to a different page than the active page are temporarily skipped until all pixels mapping to the current page are completed. Only when no more pixels require rendering within the primitive which map to the currently active frame buffer page is another frame buffer page loaded and all pixels mapping to that page are rendered. In processing a scan region which crosses a page boundary, the next pixel or pixel group to be rendered is examined to determine if it maps to the currently active frame buffer page.