Extensions to inverse displacement mapping
Yu-Jen Chen, Zong-Nan Shen, Ying‐Chieh Chen, Chun‐Fa Chang, Yung‐Yu Chuang, Jieh Hsiang · 2008
This paper presents two extensions to inverse displacement mapping, methods which attempt to render effects offered by displacement mapping, motion parallax, self-occlusion, self-shadowing and silhouette, without actually perturbing the surface geometry. The first extension, Normal-Based Curved Silhouette (NCS), allows better rendering for object's silhouette. At each step of intersection finding, NCS continuously bends the viewing ray according to the current local tangent space associated with the surface. Thus, it allows mapping a displacement map onto an arbitrary curved surface with more accurate silhouette. For the second extension, we propose a hierarchical adaptive preprocessing method that is around 10 times faster than conventional methods, allowing our space leaping approach to be used for rendering dynamic displacement maps. In addition, we propose an extension to cone step mapping. The extension, Anisotropic Cone Mapping (ACM), provides a more efficient and accurate way for calculating intersections. Anisotropic cones are used as the bounding volume for the empty space above texels, allowing faster convergence and rendering speed. Both proposed methods are suited for many realtime 3D applications because of their low memory cost and good performance in both rendering quality and speed.