Overview of the Visualize fx graphics

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May 1998 • The Hewlett-Packard JournalArticle 4 • 1998 Hewlett Packard Company

An Overview of the VISUALIZE fx Graphics

Accelerator Hardware

Three graphics accelerator products with different levels of performance are

based on varying combinations of five custom integrated circuits. In addition,

these products are the first ones from Hewlett-Packard to provide native

acceleration for the OpenGL



API.

The VISUALIZE fx family of graphics subsystems consists of three

products, fx

, fx

, and fx

, and an optional hardware texture mapping module.

These products are built around a common architecture using the same

custom integrated circuits. The primary difference between these controllers

is the number of custom chips used in each product (see Table I).

Table I

Number of custom chips in the different

VISUALIZE fx products

Product

Texture

Chip

Geometry

Chip

Raster

Chip

— 1 2

1 2 2

2 3 4

A chip-level block diagram of the VISUALIZE fx

product is shown in Figure 1.

This is the most complex configuration and also the one with the highest

performance in the product line. The VISUALIZE fx

and the VISUALIZE fx

products use subsets of the chips used in the fx

. The fx

and fx

subsystems

have support for the optional hardware-accelerated texture map module,

which contains a local texture cache for storage of texture map images. If the

texture accelerator is not present, the bus between the interface chip and the

first raster chip is directly connected.

Noel D. Scott

Daniel M. Olsen

Ethan W. Gannett

Summary of content (7 pages)

PAGE 1
An Overview of the VISUALIZE fx Graphics Accelerator Hardware Noel D. Scott Three graphics accelerator products with different levels of performance are Daniel M. Olsen based on varying combinations of five custom integrated circuits. In addition, Ethan W. Gannett these products are the first ones from Hewlett-Packard to provide native acceleration for the OpenGL API.
PAGE 2
Figure 1 A chip-level diagram of the VISUALIZE fx 6 product. Geometry Accelerator Up to 8 Texture Accelerator 200 MHz/ 33 Bits 200 MHz/ 41 Bits Geometry Chip SDRAM SDRAM RGB Texture Cache RAM 200 MHz/41 Bits Texture Chip Video Refresh Data Geometry Chip Video Chip Texture Chip Filtered Texture Data Geometry Chip PCI2.
PAGE 3
Occlusion Culling representation of a more complex part is visible. Since a bounding box, or more generally a bounding volume, completely encloses the more complex part, it is possible to know a priori that if the bounding volume is not visible then the complex part it encloses is not visible. Thus, the part that is not visible does not need to be processed through the graphics pipeline.
PAGE 4
bus connects the interface chip to the video chip. This provides video control, download of color maps, and cursor control. The second bus is a connection from each raster chip to the video chip. This path is used to provide video refresh data to display frame buffer contents. The final secondary bus is a connection from each texture chip to two of the raster chips. This path allows the flow of filtered texture data into the raster chips for combination with nontexture fragment data.
PAGE 5
Fast Virtual Texturing Texture mapping, which is wrapping a picture over a three dimensional object, has been used over the years as a key feature to enhance photorealism, reduce data set sizes, perform visual analysis, and aid in simulations (see Figure 1). Since texturing calculations are computationally expensive and memory access for large textures can be prohibitively slow, various workstation graphics vendors have provided hardware-accelerated texture mapping as a key differentiator for their product.
PAGE 6
(Figure 3). These features have made these products very appealing systems for texturing applications on workstation graphics. article. Having a centralized daemon process manage the cache allows for cache efficiency, parallel handling of texture downloads while 3D graphics rendering is occurring, and sharing textures among graphics contexts. The texture mapping performance on these systems is very competitive. The VISUALIZE fx6 texture fill rate is about twice that of the VISUALIZE fx4 texture option.
PAGE 7
Raster Chip mapping data from values to color. The features of the video chip include: The raster chip rasterizes the geometry into the frame buffer. This means it determines which pixels are to be potentially modified and, if so, whether they should be modified based on various current state values (including the contents of the z buffer). The raster chip also controls access to the various buffers that make up the frame buffer.