HIER mal ein paar Scans von einem sehr Interessanten Buch zu diesem Thema
Hehe, das Buch habe ich.
"CPU 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."
Noch viel besser ist es einfach 5 Bäume von jedem Typ fertig liegen zu haben und mit Vertexshadern passend zum Wind zu bewegen. Das spart Speicherbandbreite und die ist immer knapp.
Wenn man die Bäume gut gegen einander rotiert platziert, dann fällt niemandem auf, dass es nur 5 verschiedene Bäume gibt pro Typ gibt.
Wenn es einem Spass macht kann man sie natürlich auch auf kosten der Bandbreite on the Fly generieren, aber das ist mitnichten eine Spezialität der XBox 360.
"The console provides plenty of CPU-to-GPU bandwidth and enough computing power to procedurally render objects in real time, and the developer provides higher-level scene descriptions that allow a richer, more realistic world to be described using less storage space."
Plenty is far from unlimited.
Bandbreite tendiert dazu _immer_ knapp zu werden und einen Flaschenhals zu bilden.
"This patent (patent number 20050099417) that Microsoft was recently granted covers a method for using procedural synthesis to do real-time skinning of 3D characters. The basic idea behind the patent appears to be as follows. Artists using standard tools (i.e.., motion capture, 3D rendering tools, etc.) generate a character model along with a series of key poses in an animation for that model. This model consists of a set of bones that have been skinned with a deformable skin.
The Xenon uses the key poses that are stored in system memory and interpolates new poses as needed based on the stored poses. These new poses have skin that deforms in natural ways, and are essentially new 3D models that are generated on the fly by the procedural synthesis code. This is yet another example of the use of procedural synthesis to cut down on the amount of data stored in memory. Instead of storing a sequence of models for a character animation, the Xenon is able to generate the animation sequence dynamically from a few exemplary forms."
Gut, dass es in Europa keine Softwarepatente gibt/geben wird. Wirklich unglaublich was sich MS alles patentieren lässt. Die Technik ist so alt wie animierte 3D Charaktere alt sind. Ein Spiel wie DoA 2++ verwendet garantiert ein vergleichbares Vertexskinning und jede bessere 3D Engine der letzten 4 Jahre wohl auch.
