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Now showing 1 - 10 of 154
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    Extending Graphics Hardware For Occlusion Queries In OpenGL
    (The Eurographics Association, 1998) Bartz, Dirk; Meißner, Michael; Hüttner, Tobias; S. N. Spencer
    For interactive rendering of large polygonal objects, fast visibility queries are necessary to quickly decide whether polygonal objects are visible and need to be rendered. None of the numerous published algorithms provide visibility performance for interactive rendering of large models. In this paper, we propose an OpenGL extension for fast occlusion queries. Added after the depth test stage of the OpenGL rendering pipeline. our algorithm provides fast queries to establish the occlusion of polygonal objects. Furthermore, hardware aspects of this proposal are discussed and possible implementations on two different graphics architectures are presented.
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    Three-Dimensional Visualization of Atomic Collision Cascades
    (The Eurographics Association, 1998) Sroubek, Filip; Slavik, Pavel; Bartz, Dirk
    The paper describes a new approach to the visualization of atomic collision cascades and using the interaction with visualized data. The collision cascade is a physical phenomenon initiated by bombarding the surface of a solid with accelerated atomic particles. The process evolves in time and therefore it is necessary to develop some tools that would allow to investigate and visualize the dynamics of the process. Such tools are classi ers ( lters) that enable to select and visualize objects with specific dynamic properties. As the visualization has been done in a 3D environment a question arises how to specify effectively and user friendly both the properties and the objects in the 3D space. Several techniques are available that allow interaction in the 3D space. It has been necessary to test some of these techniques and to determine which one is the most suitable for the given application class.
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    Prefetching in a Texture Cache Architecture
    (The Eurographics Association, 1998) lgehy, Homan; Eldridge, Matthew; Proudfoot, Kekoa; S. N. Spencer
    Texture mapping has become so ubiquitous in real-time graphics hardware that many systems are able to perform filtered texturing without any penalty in fill rate. The computation rates available in hardware have been outpacing the memory access rates, and texture systems are becoming constrained by memory bandwidth and latency. Caching in conjunction with prefetching can be used to alleviate this problem. In this paper, WC introduce a prefetching texture cache architecture designed to take advantage of the access characteristics of texture mapping. The structures needed are relatively simple and arc amenable to high clock rates. To quantify the robustness of our architecture, we identify a set of six scenes whose texture locality varies over nearly two orders of magnitude and a set 01 four memory systems with varying bandwidths and latencies. Through the use of a cycle-accurate simulation, we demonstrate that even in the presence of a high-latency memory system, our architecture can attain at least 97% of the performance of a zerolatency memory system.
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    Programming Paradigms in an Object-Oriented Multimedia Standard
    (Blackwell Publishers Ltd and the Eurographics Association, 1998) Duke, D. J.; Herman, I.
    Of the various programming paradigms in use today, object-orientation is probably the most successful in terms of industrial take-up and application, particularly in the field of multimedia. It is therefore unsurprising that this technology has been adopted by ISO/IEC JTC1/SC24 as the foundation for a forthcoming International Standard for Multimedia, called PREMO. Two important design aims of PREMO are that it be distributable, and that it provides a set of media-related services that can be extended in a disciplined way to support the needs of future applications and problem domains. While key aspects of the object-oriented paradigm provide a sound technical basis for achieving these aims, the need to balance extensibility and a high-level programming interface against the realities of efficiency and ease of implementation in a distributed setting meant that the task of synthesising a Standard from existing practice was non-trivial. Indeed, in order to meet the design aims of PREMO is was found necessary to augment the basic object infrastructure with facilities and ideas drawn from other programming paradigms, in particular concepts from constraint management and data flow. This paper describes the important trade-offs that have affected the development of PREMO and explains how these are addressed through the use of specific programming paradigms.
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    A Faster Algorithm for 3D Discrete Lines
    (Eurographics Association, 1998) Boyer, V.; Bourdin, J. J.
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    Enhancing the Visualization of Characteristic Structures in Dynamical Systems
    (The Eurographics Association, 1998) Löffelmann, Helwig; Gröller, Eduard; Bartz, Dirk
    We present a thread of streamlets as a new technique to visualize dynamical systems in three-dimensional space. A trade-off is made between solely visualizing a mathematical abstraction through lowerdimensional manifolds, i.e., characteristic structures such as fixed points, separatrices, etc., and directly encoding the flow through stream lines or stream surfaces. Bundles of streamlets are selectively placed near characteristic trajectories. An over-population of phase space with occlusion problems as a consequence is omitted. On the other hand, information loss is minimized since characteristic structures of the flow are still illustrated in the visualization.
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    An Improved Z-Buffer CSG Rendering Algorithm
    (The Eurographics Association, 1998) Stewart, Nigel; Leach, Geoff; John, Sabu; S. N. Spencer
    We present an improved z-buffer based CSG rendering algorithm, based on previous techniques using z-buffer parity based surface clipping. We show that while this type of algorithm has been reported as requiring O(n2), (where n is the number of primitives), an O(lcn) (where k is depth complexity) algorithm may be substituted. For cases where k is less than n this translates into a significant performance gain.
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    is98
    (1998)
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    Fast Feature-Based Metamorphosis and Operator Design
    (Blackwell Publishers Ltd and the Eurographics Association, 1998) Lee, Tong-Yee; Lin, Young-Ching; Sun, Y.N.; Lin, Leeween
    Metamorphosis is a powerful visual technique, for producing interesting transition between two images or volume data. Image or volume metamorphosis using simple features provides flexible and easy control of visual effect. The feature-based image warping proposed by Beier and Neely is a brute-force approach. In this paper, first, we propose optimization methods to reduce their warping time without noticeable loss of image quality. Second, we extend our methods to 3D volume data and propose several interesting warping operators allowing global and local metamorphosis of volume data.
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    Sixth Eurographics Workshop on Programming Paradigms in Graphics (WPPG97)
    (Blackwell Publishers Ltd and the Eurographics Association, 1998) Arbab, Farhad; Slusallek, Philipp