Direct lighting on meso-structured surfaces with area light sources

We present a novel direct lighting rendering method for static scenes with meso-structured surfaces and multiple area light sources. We use coarse geometry models with textures bound on them as inputs. The textures contain not only color maps, but also height field maps to represent the small concave and convex details for meso-structured surfaces. We explore traditional radiosity process as the main frame of our algorithm, and extend radiosity to directional radiosity for approximating light transportation on meso-structured surfaces. In pre-processing step, first, the form factors between the triangles of coarse models and the patches of area light sources are pre-computed. Then the directional radiosity of each triangle is computed by gathering irradiance according to directions sampled uniformly on the hemi-sphere of them. At last, directional radiosity of a vertex is estimated according to the directional radiosity of triangles passing through this vertex. For each frame, we combine relief texture mapping with directional radiosity to shade meso-structured surface. The experiment results show that our method has very similar quality and better time performance for rendering the scenes with meso-structured surfaces and multiple area light sources compared with SM+RTM method.