EGGH: SIGGRAPH/Eurographics Workshop on Graphics Hardware

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Browsing EGGH: SIGGRAPH/Eurographics Workshop on Graphics Hardware by Subject "1.3.7 [Computer Graphics] Three Dimensional Graphics and Realism"

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    Design Of A High Performance Volume Visualization System
    (The Eurographics Association, 1997) Lichtenbelt, Barthold; A. Kaufmann and W. Strasser and S. Molnar and B.-O. Schneider
    Visualizing three dimensional discrete datasets has been a topic of many research projects and papers in the past decade. We discuss the issues that come up when designing a whole computer system capable of visualizing these datasets in real time. We explain the three way chicken and egg problem and discuss Hewlett- Packard s effort at breaking it with the Voxelator API extensions to OpenGL. We enumerate what a good hardware design should accomplish. We discuss what system issues are important and show how to integrate volume visualization hardware in one of Hewlett-Packard s graphics accelerators, the VISUALIZE-48XP. We show why the Voxelator is an efficient and well designed API by explaining how various existing hardware engines will easily fit into the Voxelator framework.
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    Texture Tile Visibility Determination For Dynamic Texture Loading
    (The Eurographics Association, 1998) Goss, Michael E.; Yuasa, Kei; S. N. Spencer
    Three-dimensional scenes have become an important form of content deliverable through the Internet. Standard formats such as Virtual Reality Modeling Language (VRML) make it possible to dynamically download complex scenes from a server directly to a web browser. However, limited bandwidth between servers and clients presents an obstacle to the availability of more complex scenes, since geometry and texture maps for a reasonably complex scene may take many minutes to transfer over a typical telephone modem link. This paper addresses one part of the bandwidth bottleneck, texture transmission. Current display methods transmit an entire texture to the client before it can be used for rendering. We present an alternative method which subdivides each texture into tiles, and dynamically determines on the client which tiles are visible to the user. Texture tiles are requested by the client in an order determined by the number of screen pixels affected by the texture tile, so that texture tiles which affect the greatest number of screen pixels are transmitted first. The client can render images during texture loading using tiles which have already been loaded. The tile visibility calculations take full account of occlusion and multiple texture image resolution levels, and are dynamically recalculated each time a new frame is rendered. We show how a few additions to the standard graphics hardware pipeline can add this capability without radical architecture changes, and with only moderate hardware cost. The addition of this capability makes it practical to use large textures even over relatively slow network connections.