Fast collision detection using the A-buffer

This paper presents a novel and fast image-space collision detection algorithm with the A-buffer, where the GPU computes the potentially colliding sets (PCSs), and the CPU performs the standard triangle intersection test. When the bounding boxes of two objects intersect, the intersection is passed to the GPU. The object surfaces in the intersection are rendered into the A-buffer. Rendering into the A-buffer is up to eight-times faster than the ordinary approaches. Then, PCSs are computed by comparing the depth values of each texel of the A-buffer. A PCS consists of only two triangles. The PCSs are read back to the CPU, and the CPU computes the intersection points between the triangles. The proposed algorithm runs extremely fast, does not require any preprocessing, can handle dynamic objects including deformable and fracturing models, and can compute self-collisions. Such versatility and performance gain of the proposed algorithm prove its usefulness in real-time applications such as 3D games.