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Show DISPLACEMENT VALUE --------- i ______ _ VIEWING SCREEN TEXTURE MODEL BASE PLANE LIGHT RAYS Figure 17: Generation of a Surface Perturbation Texture Map 35 intersects an object then an entry is made into the ray tree. The ray tree contains such information as the surface intersection point, the surface intersection normal, and various surface attributes such as surface color, surface texture, and surface lighting parameters. Any of these attributes n1ay be perturbed via a texture map to create a realistic textured surface. This thesis describes the effects of perturbing the actual surface intersection point and corresponding surface normal. Surface perturbations on an object are calculated after an intersection with a ray and an object is encountered. A transformation of the surface intersection point determines the index into the surface perturbation map and a displacement scalar is fetched. The calculation also requires the surface intersection point (inter-sect. x, intersect.y, intersect.z) and the surface norn1al vector (normal.x, normal.y, normal.z). The surface intersection point is then modified by the product of the |
