Terrain Streaming on the Playstation® 3
By: Tyler Robertson.
Supervisor: Gary Brubaker
Masters of Interactive Technology degree conferred May 1, 2009
Thesis / Project completed: May 1, 2009

This project explorers issues that come along with streaming heightmap data from the DVD on the Playstation 3. By maximizing streaming on a console, games can minimize load-times and avoid lengthy pre-installs. This project looks at two different ways terrain data can be laid out on the disc, two methods for reading level-of-detail data and three algorithms to schedule read requests. The end result is a set of systems that can support camera velocities of up to 108,000 km/hr while flying over a heightmap of the Big Island of Hawaii with 30 meter resolution.

Because Sony does not allow access to the graphics card in Linux, a software wireframe renderer needed to be created so that the terrain could be visualized on the screen. This project uses two Synergetic Processing Units in pipeline to transform, clip, and rasterize lines. The software renderer is able to draw approximately 1 million triangles per second at a 1280 x 720 resolution.

The project converts a standard binary terrain file into a chunked format. During this preprocessing step the terrain is split into chunks and level-of-detail data is generated. The result is a single file holding two copies of the terrain data. One copy has columns contiguous in the file and the other copy lays chunks out according to a space-filling Hilbert curve.

An input system reads data from the DVD asynchronously and the terrain system takes care of requesting terrain chunks and recycling vertex and index buffers. The systems support changing algorithms at run-time so the user can switch data layout, level-of-detail source and request scheduling on the fly.

For data collection, a camera travels a pre-recorded path so that the same chunks of terrain would be requested. Several statistics were written to file and the results compared. In general the configuration which provided the best results was a data layout using Hilbert curves, a level-of-detail source of per-level streams and a scanning scheduling algorithm.

Download entire thesis (.pdf)