Date:
Thursday , July 18, 2002
Author:
Kyle Bennett
Google +1

Radeon 9700 White Paper

A very well written white paper covering the major internal workings of the DX9 compliant ATi R300 Visual Processing Unit along with our thoughts.

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3D Rendering Engine:

Once all of the triangles that make up a 3D scene have been arranged and lit as necessary, the next step in rendering the scene is to fill in the triangles with individual pixels. The color of each pixel is determined by the textures that are applied, the lighting conditions, and the material properties assigned to the triangle. This process is controlled by pixel shaders, which are small programs that are uploaded to the graphics chip and executed by the rendering engine.

The RADEON 9700 is the first graphics processor to be able to render up to eight pixels simultaneously. This is accomplished by eight parallel 128-bit rendering pipelines, each with its own independent texture unit and pixel shader engine. The texture unit of each rendering pipeline can sample up to 16 textures in a single rendering pass. These textures can be one-, two-, or three-dimensional, with bilinear, trilinear, or anisotropic filtering applied depending on the desired quality level.

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The advanced DirectX 9.0 pixel shader engines of the RADEON 9700 are designed to handle floating point operations, which provide increased range and precision compared to the integer operations used in earlier designs. The engines provide up to 96-bits of precision for all calculations, which is a necessity for re-creating studio-quality visual effects.

It is pretty obvious that the VPU is extremely powerful simply from the information given about it being able to render eight pixels while using up to 16 textures in a single pass. Still, what may be a bit ambiguous is the statement about floating point operations. ATi states it will give an increased range and precision compared to their earlier integer operations. I think they really have something to blow their own horn about here for sure. This FPU ability is something that will be extremely important in our next-gen gaming experiences. Using integer operations there was no possible way to shade or transition colors as precisely as those calculations where being rounded up or down and “true” data values not given. So the mention of studio-quality visual effects is really very accurate. These tools in the hands of the proper programmers can certainly lead to a more pre-rendered CG look in real time. Still though, while ATI is pushing the envelope at this time, we still have a long way to go but as The Carmack has stated here recently we are getting closer.

The RADEON 9700 pixel shader engines also achieve greater efficiency by being able to process up to three instructions simultaneously – one texture look-up, one texture address operation, and one color operation. Since pixel shaders typically contain a mixture of these three types of operations, this capability ensures maximum engine utilization and performance.

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The RADEON 9700 is the first product to incorporate SMARTSHADER 2.0, ATI’s second generation of programmable vertex and pixel shader technology. Designed to be much more powerful and flexible than first-generation shader technology, SMARTSHADER 2.0 will enable the transition of movie-quality effects into real-time games and other interactive applications. As the first complete implementation of DirectX 9.0, the industry standard API for graphics, SMARTSHADER 2.0 will also be fully compatible with current and future revisions of OpenGL.

SMARTSHADER 2.0 is of course more of the same that we have seen with the 8500 in the past. This basically allows the gav-devs to create their groups of instruction sets and their own effects while already have a bevy to choose from inside the DX9 standard. Don't be fooled that while they have a lot in common, they are not the same. This DX9 part will allow for up to 64 shader instructions to be supported in hardware for the DX9 API.

RADEON 9700 also introduces SMOOTHVISION 2.0, which represents the latest in image quality enhancement techniques for any 3D application. The SMOOTHVISION 2.0 implementations of full scene anti-aliasing and anisotropic filtering deliver greater performance, quality and flexibility than any existing solution.

For more detailed information on SMOOTHVISION 2.0, SMARTSHADER 2.0, and DirectX 9.0, please visit www.ati.com to download the white papers or view the interactive Flash demos.