Hierarchical Image-Based Rendering Using Texture Mapping Hardware

Multi-layered depth images containing color and normal information for subobjects in a hierarchical scene model are precomputed with standard zbuffer hardware for six orthogonal views. These are adaptively selected according to the proximity of the viewpoint, and combined using hardware texture mapping to create “reprojected” output images for new viewpoints. (If a subobject is too close to the viewpoint, the polygons in the original model are rendered.) Specific z-ranges are selected from the textures with the hardware alpha test to give accurate 3D reprojection. The OpenGL color matrix is used to transform the precomputed normals into their orientations in the final view, for hardware shading.