| a link to the past 2005-04-23, 12:38 am |
| http://news.teamxbox.com/xbox/8111/...cs-Chip-Patent/
Xbox 360 Graphics Chip Patent?
By: César A. Berardini - "Cesar"
Apr. 22nd, 2005 3:39 pm
Today we bring you a new patent that was was approved on March 29th by the
United States Patent and Trademark Office, in which ATI, Microsoft's
graphics chip partner for the Xbox 360, is patenting a "method and apparatus
for supporting anti-aliasing oversampling in a video graphics system that
utilizes a custom memory for storage of the frame buffer." In layman terms,
that is embedded video RAM for the GPU to use it as a frame buffer.
In a world exclusive, TeamXbox was the first publication to reveal the
existence of the embedded video RAM back in February, 2004. What a track
record, eh? First it was the IBM-Microsoft deal, then this ;)
This new patent, filed in August, 2002, exposes a custom memory used by the
graphic chip for storage of the frame buffer.
This custom memory has been created mostly to perform anti-aliasing
operations and help overcometoday's biggest problem in graphics chips:
memory bandwidth.
Generally, the present invention provides method and apparatus for
supporting anti-aliasing oversampling in a video graphics system that
utilizes a custom memory for storage of the frame buffer. The custom memory
includes a memory array that stores the frame buffer as well as a data path
that performs at least a portion of the blending operations associated with
pixel fragments generated by a graphics procesor. The fragments produced by
a graphics procesor are oversampled fragments such that each fragment may
include a plurality of samples. If the sample set for a particular pixel
location can be compressed, the compressed sample set is stored within the
frame buffer of the custom memory circuit. However, if such compression is
not possible, pointer information is stored within the frame buffer on the
custom memory, and a sample memory controller included on the graphics
procesor maintains a complete sample set for the pixel location within a
sample memory. When the sample memory controller maintains a complete sample
set for a pixel location, the frame buffer stores a pointer corresponding to
the location of the sample set.
The invention can be better understood when viewing the following image:
http://media.teamxbox.com/dailypost...ox360_edram.gif
The figure illustrates a block diagram of a "graphics processing system"
that supports oversampling anti-aliasing. The system includes a graphics
processor, a sample memory and a custom memory module. The graphics
processor, the custom memory, and the sample memory may each be individual
integrated circuits.
Embedded DRAM is expensive, because it's very similar to microprocessors
cache memory, so that is why the patent explains that in order to keep costs
low, the amount of additional logic included on this custom memory may be
minimized. Therefore, although some of the circuitry always found within the
video graphics system has been moved onto this new custom memory invention,
some functions still remain within the graphics processor in order to keep
the production costs low for the custom memory.
So what does all this mumbo jumbo mean? It means we'll get games running at
720p HDTV resolution, that is 1280x720, will full screen anti-aliasing with
almost no impact on framerate. Imagine Project Gotham Racing 3 or those
badass Unreal Engine 3-powered games running at some 60 FPS, with full
screen anti-aliasing and anisotropic filtering taken to the max!
It's a hardcore gamer's dream come true!
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