Computer graphics processing and selective visual display system – Computer graphics display memory system – Plural storage devices
Reexamination Certificate
2002-07-19
2004-11-09
Tung, Kee M. (Department: 2676)
Computer graphics processing and selective visual display system
Computer graphics display memory system
Plural storage devices
C345S519000, C345S544000
Reexamination Certificate
active
06816162
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the field of computer graphics and, more particularly, to a high performance graphics system which implements super-sampling.
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2. Description of the Related Art
A computer system typically relies upon its graphics system for producing visual output on the computer screen or display device. Early graphics systems were only responsible for taking what the processor produced as output and displaying that output on the screen. In essence, they acted as simple translators or interfaces. Modem graphics systems, however, incorporate graphics processors with a great deal of processing power. They now act more like coprocessors rather than simple translators. This change is due to the recent increase in both the complexity and amount of data being sent to the display device. For example, modern computer displays have many more pixels, greater color depth, and are able to display images that are more complex with higher refresh rates than earlier models. Similarly, the images displayed are now more complex and may involve advanced techniques such as anti-aliasing and texture mapping.
As a result, without considerable processing power in the graphics system, the CPU would spend a great deal of time performing graphics calculations. This could rob the computer system of the processing power needed for performing other tasks associated with program execution and thereby dramatically reduce overall system performance. However, with a powerful graphics system, the CPU may send a request to the graphics system stating: “draw a box at these coordinates”. The graphics system then draws the box, freeing the processor to perform other tasks.
Since graphics systems typically perform only a limited set of functions, they may be customized and therefore far more efficient at graphics operations than the computer's general-purpose central processor. Graphics system processors are specialized for computing graphical transformations, so they tend to achieve better results than the general-purpose CPU used by the computer system. In addition, they free up the computer's CPU to execute other commands while the graphics system is handling graphics computations. The popularity of graphical applications, and especially multimedia applications, has made high performance graphics systems a common feature of computer systems. Most computer manufacturers now bundle a high performance graphics system with their systems.
Early graphics systems were limited to performing two-dimensional (2D) graphics. Their functionality has since increased to support three-dimensional (3D) wire-frame graphics, 3D solids, and now includes support for three-dimensional (3D) graphics with textures and special effects such as advanced shading, fogging, alpha-blending, and specular highlighting.
While the number of pixels is an important factor in determining graphics system performance, another factor of equal import is the quality of the image. Various methods are used to improve the quality of images, such as anti-aliasing, alpha blending, and fogging. While various techniques may be used to improve the appearance of computer graphics images, they also have certain limitations. In particular, they may introduce their own image aberrations or artifacts, and are typically limited by the density of pixels displayed on the display device.
As a result, a graphics system is desired which is capable of utilizing increased performance levels to increase not only the number of pixels rendered, but also the quality of the image rendered. In addition, a graphics system is desired which is capable of utilizing increases in processing power to improve graphics effects.
Prior art graphics systems have generally fallen short of these goals. Prior art graphics systems use a conventional frame buffer for refreshing pixel/video data on the display. The frame buffer stores rows and columns of pixels that exactly correspond to respective row and column locations on the display. Prior art graphics systems render 2D and/or 3D images or objects into the frame buffer in pixel form, and then read the pixels from the frame buffer to refresh the display. To reduce visual artifacts that may be created by refreshing the screen at the same time as the frame buffer is being updated, most graphics systems' frame buffers are double-buffered.
To obtain images that are more realistic, some prior art graphics systems have implemented super-sampling by generating more than one sample per pixel. By calculating more samples than pixels (i.e., super-sampling), a more detailed image is calculated than can be displayed on the display device. For example, a graphics system may calculate 4, 8 or 16 samples for each pixel to be output to the display device. After the samples are calculated, they are then combined, convolved, or filtered to form the pixels that are stored in the frame buffer and then conveyed to the display device. Using pixels formed in this manner may create a more realistic final image because overly abrupt changes in the image may be smoothed by the filtering process.
As used herein, the term “sample” refers to calculated information that indicates the color of the sample and possibly other information, such as depth (z), transparency, etc., of a particular point on an object or image. For example, a sample may comprise the following component values: a red value, a green value, a blue value, a z value, and an alpha value (e.g., representing the transparency of the sample). A sample may also comprise other information, e.g., a z-depth value, a blur value, an intensity value, brighter-than-bright information, and an indicator that the sample consists partially or completely of control information rather than color information (i.e., “sample control information”).
When a graphics system implements super-sampling, the graphics system is typically required to select sample positions for the samples, generate samples at the selected sample positions, read a plurality of samples, i.e., sample data, corresponding to the area or support region of a filter, and then filter the samples within the filter region to generate an output pixel. To generate pixel values from sample data in real time as needed for a video data stream, improved methods are desired for managing the sample data used to generate pixel values for each pixel location.
SUMMARY
The problems set forth above may at least in part be solved by a data management system and method for real time calculation of pixel values from sample data. The elements of such a data management system may include a sample buffer that is configured to store sample data in rows of sample bins. Sample data for one or more sample positions may be stored in each sample bin and the rows of sample bins define a region in sample space. Sample data includes one or more of sample location, color values, transparency value, and depth. A bin scanline cache may be configured to store P rows of sample bins copied from P sequential rows of the sample buffer from a specified portion of sample space. N sequential rows of the P rows may be approximately vertically centered on a selected pixel location in sample space. N and P are positive integers, and P is greater than or equal to N. A sample cache may be configured to store an N×N sample bin array of sample bins copied from N sequential columns of the N sequential rows of the bin scanline cache. The sample bins contained in the N×N sample bin array may be approximately centered on the selected pixel location in sample space.
A sample processor may be configured to determine pixel values for the selected pixel location by processing one or more sample values stored in the sample cache. A sample controller may be configured to select a sequence of pixel locations in sample space that corresponds to a sequence of pixels in a video data stream. The sample controller may execute, for each pixel location in the sequence, a set of operations that includes one or more of: a
Deering Michael F.
Naegle Nathaniel David
Taneja Nimita J.
Hood Jeffrey C.
Meyertons Hood Kivlin Kowert & Goetzel P.C.
Sun Microsystems Inc.
Tung Kee M.
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