Creating vast game worlds: experiences from Avalanche Studios

ABSTRACT

Creating vast game environments introduces several complex issues that are not present in smaller game worlds. As the size of the world grows issues with floating point precision arise, causing objects to jitter, simulation to become unstable, and rendering to exhibit artifacts. These problems were very apparent during development of Just Cause 2 and had to be addressed. Depending on location in the game animated foliage exhibited vertices snapping up to decimeter sized increments. Trees were at times jumping instead of swaying. In the distance there were severe z-fighting issues. Shadows were sometimes unstable. The shadow acne that occurred could not be effectively dealt with using the standard depth bias approach. Additionally, sampling depth buffers using vendor-provided methods yielded insufficient precision. Several techniques were developed to reduce precision loss at every part of the pipeline.