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Item Algorithms for Division Free Perspective Correct Rendering(The Eurographics Association, 2000) Barenbrug, B.; Peters, F.J.; Overveld, C.W.A.M. van; I. Buck and G. Humphreys and P. HanrahanWell known implementations for perspective correct rendering of planar polygons require a division per rendered pixel. Such a division is better to be avoided as it is an expensive operation in terms of silicon gates and clock cycles. In this paper we present a family of efficient midpoint algorithms that can be used to avoid division operators. These algorithms do not require more than a small number of additions per pixel. We show how these can be embedded in scan line algorithms and in algorithms that use mipmaps. Experiments with software implementations show that the division free algorithms are a factor of two faster, provided that the polygons are not too small. These algorithms are however most profitable when realised in hardware.Item GI-Cube: An Architecture for Volumetric Global Illumination and Rendering(The Eurographics Association, 2000) Dachille, Frank; Kaufman, Arie; I. Buck and G. Humphreys and P. HanrahanThe power and utility of volume rendering is increased by global illumination. We present a hardware architecture, GI-Cube, designed to accelerate volume rendering, empower volumetric global illumination, and enable a host of ray-based volumetric processing. The algorithm reorders ray processing based on a partitioning of the volume. A cache enables efficient processing of coherent rays within a hardware pipeline. We study the flexibility and performance of this new architecture using both high and low level simulations.Item Towards Interactive Bump Mapping with Anisotropic Shift-Variant BRDFs(The Eurographics Association, 2000) Kautz, Jan; Seidel, Hans-Peter; I. Buck and G. Humphreys and P. HanrahanIn this paper a technique is presented that combines interactive hardware accelerated bump mapping with shift-variant anisotropic reflectance models. An evolutionary path is shown how some simpler reflectance models can be rendered at interactive rates on current low-end graphics hardware, and how features from future graphics hardware can be exploited for more complex models. We show how our method can be applied to some well known reflectance models, namely the Banks model,Ward s model, and an anisotropic version of the Blinn-Phong model, but it is not limited to these models. Furthermore, we take a close look at the necessary capabilities of the graphics hardware, identify problems with current hardware, and discuss possible enhancements.