This article is the first in a series that takes an in-depth look at the Xbox 360, with a particular focus on the hardware that makes it tick. I'm talking about the triple-core PowerPC processor that forms the heart of the new console, as well as the ATI GPU. In Part I, I take a look at the nuts and bolts of how Microsoft plans to implement one of the most hyped of the new console's many capabilities: procedural synthesis.




The Xbox 360's solution to this problem is to store high-level descriptions of objects in main memory, and have the GPU procedurally generate the geometry (i.e., the vertex data) of the objects on the fly. So in the case of our forest, main memory stores information about the tree, like the type, size, location of each leaf, etc., along with other relevant data like the direction of the prevailing wind. This information is passed into the Xbox 360's Xenon CPU, where the vertex data that defines the polygons out of which the tree is made are generated by one or more running threads. These threads then feed that vertex data directly into the GPU (by way of a special set of write buffers in the L2 cache, but more on that later). The GPU then takes that vertex information and renders the trees normally, just as if it had gotten that information from main memory.




The article also covers some high-level aspects of the Xbox CPU's design, discussing how those parts work together to synthesize in-game objects on the fly.
http://feeds.feedburner.com/arstechnica/BAaf?m=534