Journal of Graphics Tools, GPU and Game Tools, 10(4):23-32, January 2005.
We present a new and efficient method to compute the intersection point between a convex planar quadrilateral and a ray. Contrary to the Schlick-Subrenat intersection test, the bilinear coordinates of the intersection point are computed only for rays that hit the quadrilateral. Rays that do not hit the quadrilateral are rejected early. Our method is up to 40% faster compared to the algorithm presented by Schlick and Subrenat. The intersection test we present is based on the Muller-Trumbore ray-triangle intersection algorithm. The new test is at least as fast as two ray triangle intersection tests, and yields bilinear coordinates with no discontinuities in the isoparametrics. Source code implementing the intersection test is available online.
