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Item A Virtual Memory System Organization for Bit-Mapped Graphics Displays(The Eurographics Association, 1989) Barkans, Anthony C.; Richard Grimsdale and Wolfgang StrasserDescribed is a display sub-system, designed for support of a very high speed rendering engine. It provides high-performance graphics to an enVironment that consists of a hierarchy of resizable windows. The concept of virtual memory has been applied with the organization of the virtual to physical address spaces having a unique mapping that fits the organization of a bit-mapped graphics memory display.Item Real-Time Bump Map Synthesis(The Eurographics Association, 2001) Kautz, Jan; Heidrich, Wolfgang; Seidel, Hans-Peter; Kurt Akeley and Ulrich NeumannIn this paper we present a method that automatically synthesizes bump maps at arbitrary levels of detail in real-time. The only input data we require is a normal density function; the bump map is generated according to that function. It is also used to shade the generated bump map. The technique allows to infinitely zoom into the surface, because more (consistent) detail can be created on the fly. The shading of such a surface is consistent when displayed at different distances to the viewer (assuming that the surface structure is self-similar). The bump map generation and the shading algorithm can also be used separately.Item Point-driven Generation of Images from a Hierarchical Data Structure(The Eurographics Association, 1988) Jong, Dirk de; Siobbe, Paul van; Splunter, Marinus van; A. A. M.KuijkIn this paper, a system IS described which renders an image from a hierarchical data structure in a point-driven way. The data structure allows dynamic color mapping and arbitrary affine transformat·ons of objects with respect to their parent coordinate system. The point driven method allows for easy VLSI implementation, efficient use oj memory and exploitation of parallelism.Item Memory Access Patterns of Occlusion-Compatible 3D Image Warping(The Eurographics Association, 1997) Murk, William R.; Bishop, Gary; A. Kaufmann and W. Strasser and S. Molnar and B.-O. SchneiderMcMillan and Bishop s 3D image warp can be efficiently implemented by exploiting the coherency of its memory accesses. We analyze this coherency, and present algorithms that take advantage of it. These algorithms traverse the reference image in an occlusion-compatible order, which is an order that can resolve visibility using a painter s algorithm. Required cache sizes are calculated for several one-pass 3D warp algorithms, and we develop a two-pass algorithm which requires a smaller cache size than any of the practical one-pass algorithms. We also show that reference image traversal orders that are occlusion-compatible for continuous images are not always occlusion-compatible when applied to the discrete images used in practice.Item Z3: An Economical Hardware Technique for High-Quality Antialiasing and Transparency(The Eurographics Association, 1999) Jouppi, Norman P.; Chang, Chun-Fa; A. Kaufmann and W. Strasser and S. Molnar and B.- O. SchneiderIn this paper we present an algorithm for low-cost hardware antialiasing and transparency. This technique keeps a central Z value along with compact floating-point Z gradients in the X and Y dimensions for each fragment within a pixel (hence the name Z3). It uses a small fixed amount of storage per pixel. If the visible complexity of the pixel exceeds the storage space available for the pixel, the minimum number of fragments having the closest Z values are merged. This combines different fragments from the same surface, resulting in both storage and processing efficiency. When operating with opaque surfaces, Z3 can provide superior image quality over sparse supersampling methods that use eight samples per pixel while using storage for only three fragments. Z3 also makes the use of large numbers of samples (e.g., 16) feasible in inexpensive hardware, enabling higher quality images. It is simple to implement because it uses a small fixed number of fragments per pixel. Z3 can also provide order-independent transparency even if many transparent surfaces are present. Moreover, unlike the original A-buffer algorithm it correctly antialiases interpenetrating transparent surfaces because it has three-dimensional Z information within each pixel.Item PixelFlow: The Realization(The Eurographics Association, 1997) Eyles, John; Molnar, Steven; Poulton, John; Greer, Trey; Lastra, Anselmo; England, Nick; Westover, Lee; A. Kaufmann and W. Strasser and S. Molnar and B.-O. SchneiderPixelFlow is an architecture for high-speed, highly realistic image generation, based on the techniques of object-parallelism and image composition. Its initial architecture was described in [MOLN92]. After development by the original team of researchers at the University of North Carolina, and codevelopment with industry partners, Division Ltd. and Hewlett- Packard, PixelFlow now is a much more capable system than initially conceived and its hardware and software systems have evolved considerably. This paper describes the final realization of PixelFlow, along with hardware and software enhancements heretofore unpublished.Item Interactive Rendering of Atmospheric Scattering Effects Using Graphics Hardware(The Eurographics Association, 2002) Dobashi, Yoshinori; Yamamoto, Tsuyoshi; Nishita, Tomoyuki; Thomas Ertl and Wolfgang Heidrich and Michael DoggettTo create realistic images using computer graphics, an important element to consider is atmospheric scattering, that is, the phenomenon by which light is scattered by small particles in the air. This effect is the cause of the light beams produced by spotlights, shafts of light, foggy scenes, the bluish appearance of the earth s atmosphere, and so on. This paper proposes a fast method for rendering the atmospheric scattering effects based on actual physical phenomena. In the proposed method, look-up tables are prepared to store the intensities of the scattered light, and these are then used as textures. Realistic images are then created at interactive rates by making use of graphics hardware.Item TRIANGLECASTER Extensions To 3BTexturing Units For Accelerated Volume Rendering(The Eurographics Association, 1999) Knittel, Gunter; A. Kaufmann and W. Strasser and S. Molnar and B.- O. SchneiderWe discuss hardware extensions to 3D-texturing units, which are very small but nevertheless remove some substantial performance limits typically found when using a 3D-texturing unit for volume rendering. The underlying algorithm uses only a slight modification of existing method, which limits negative impacts on application software. In particular, the method speeds up the compositing operation, improves texture cache eflciency and allows for early ray termination and empty space skipping. Early ray termination can not be used in the traditional approach. Simulations show that, depending on data set properties, the performance of readily available, low-cost PC graphics accelerators is already suflcient for real-time volume visualization. Thus, in terms ofperformance, the TRIANGLECASTER-extensions can make dedicated volume rendering accelerators unnecessary.Item Quadratic Bezier Triangles As Drawing Primitives(The Eurographics Association, 1998) Bruijns, J.; S. N. SpencerWe propose to use quadratic Bezier triangles as additional drawing primitives: quadratic Bezier triangles require much less model data for faithful representation of curved surfaces than planar triangles. Therefore, they require less storage and/or transmission capacity. Furthermore, they allow automatic level-of-detail. Finally, they result in considerable savings in model-view transformations and lighting calculations. We present two algorithms for rendering these triangles, each of which can be easily incorporated in hardware render systems currently used for planar triangles.Item Adaptive Texture Maps(The Eurographics Association, 2002) Kraus, Martin; Ertl, Thomas; Thomas Ertl and Wolfgang Heidrich and Michael DoggettWe introduce several new variants of hardware-based adaptive texture maps and present applications in two, three, and four dimensions. In particular, we discuss representations of images and volumes with locally adaptive resolution, lossless compression of light fields, and vector quantization of volume data. All corresponding texture decoders were successfully integrated into the programmable texturing pipeline of commercial off-the-shelf graphics hardware.