  We present in this paper several improvements for computing shortest path
maps using OpenGL shaders. The approach explores GPU rasterization as a way to
propagate optimal costs on a polygonal 2D environment, producing shortest path
maps which can efficiently be queried at run-time. Our improved method relies
on Compute Shaders for improved performance, does not require any CPU
pre-computation, and handles shortest path maps both with source points and
with line segment sources. The produced path maps partition the input
environment into regions sharing a same parent point along the shortest path to
the closest source point or segment source. Our method produces paths with
global optimality, a characteristic which has been mostly neglected in animated
virtual environments. The proposed approach is particularly suitable for the
animation of multiple agents moving toward the entrances or exits of a virtual
environment, a situation which is efficiently represented with the proposed
path maps.
