Talisman was a Microsoft project to build a new 3D graphics architecture based on quickly compositing 2D "sub-images" onto the screen, an adaptation of tiled rendering.
In theory, this approach would dramatically reduce the amount of memory bandwidth required for 3D games and thereby lead to lower-cost graphics accelerators.
From this world view, a series of polygons (typically triangles) is created that approximates the original models as seen from a particular viewpoint, the camera.
As scene complexity increased, the need to re-generate the geometry for what was essentially a fixed set of objects started to become a bottleneck of its own.
At the time a number of companies were exploring this path, the so-called "transform and lighting" cards or T&L, but the complexity and cost of the systems appeared considerable.
Talisman was a complete suite of software and hardware that attempted to solve the tiled rendering problem.
In Talisman, image buffers were broken down into 32 x 32 pixel "chunks" that were individually rendered using the 3D objects and textures provided by the CPU.
In a conventional 3D system, geometry is periodically generated, sent to the card for composition, composed into a framebuffer, and then eventually picked up by the video hardware for display.
If it could not, say because the camera had moved too much since the last full update, the CPU was asked to provide new geometry for that chunk, which the card then rendered and placed back in storage.
This is an interesting analog with the Atari 2600, which uses a similar system to render 2D images on the screen, a method known as "racing the beam".
In particular, the PixelFlow system developed at a Hewlett-Packard research lab at the University of North Carolina at Chapel Hill can be considered Talisman's direct parent.
[2] When Talisman was first made widely public at the 1996 SIGGRAPH meeting, they promised a dramatic reduction in the cost of implementing a graphics subsystem.
Cirrus Logic would provide a VLSI chip that would retrieve data placed in memory by the MSP, apply effects, and send it off for display.
Unlike the new 3D cards coming to market at the time, Talisman systems would have to be able to ask the CPU to re-render portions of the image in order to update their chunks.
Cirrus Logic and Samsung both gave up on the system some time in 1997, leading Microsoft to abandon plans to release Escalante in 1997, and to external observers it appeared the entire project was dead.
[5] There was a brief rebirth soon after, however, when Fujitsu claimed to be working on a single-chip implementation that would be available in 1998, with rumors of similar projects at S3 Graphics and ATI Technologies.
The idea of using "chunks" to sort the display has also been used in a small number of cards, referred to as tile based rendering.
Many graphics processors specifically designed for mobile devices (such as cell phones) employ a tile-based approach.