Edge-enhancement: an algorithm for real-time

In this paper, we propose an algorithm for enhancing edges of real-time non-photorealistic renderings. It is based on the edge map, a 2D texture that encodes visually important edges of 3D scene objects, and includes silhouette edges, border edges, and crease edges. The edge map allows us to derive and augment a wide range of nonphotorealistic rendering styles. Furthermore, the algorithm is designed to be orthogonal to complementary realtime rendering techniques. The implementation is based on multipass rendering: First, we extract geometrical properties of 3D scene objects generating image-space data similar to G-buffers. Next, we extract discontinuities in the image-space data using common graphics hardware to emulate image-processing operations. In subsequent rendering passes, the algorithm applies texture mapping to combine the edge map with 3D scene objects