76 results
Search Results
Now showing 1 - 10 of 76
Item A Parallel Approach to Compression and Decompression of Triangle Meshes using the GPU(The Eurographics Association and John Wiley & Sons Ltd., 2017) Jakob, Johannes; Buchenau, Christoph; Guthe, Michael; Bærentzen, Jakob Andreas and Hildebrandt, KlausMost state-of-the-art compression algorithms use complex connectivity traversal and prediction schemes, which are not efficient enough for online compression of large meshes. In this paper we propose a scalable massively parallel approach for compression and decompression of large triangle meshes using the GPU. Our method traverses the input mesh in a parallel breadth-first manner and encodes the connectivity data similarly to the well known cut-border machine. Geometry data is compressed using a local prediction strategy. In contrast to the original cut-border machine, we can additionally handle triangle meshes with inconsistently oriented faces. Our approach is more than one order of magnitude faster than currently used methods and achieves competitive compression rates.Item Prefetching in a Texture Cache Architecture(The Eurographics Association, 1998) lgehy, Homan; Eldridge, Matthew; Proudfoot, Kekoa; S. N. SpencerTexture 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.Item VIZARD - Visualization Accelerator for Realtime Display(The Eurographics Association, 1997) Knittel, Günter; Straßer, Wolfgang; A. Kaufmann and W. Strasser and S. Molnar and B.-O. SchneiderVolume rendering has traditionally been an application for supercomputers, workstation networks or expensive special-purpose hardware. In contrast, this report shows how far we have reached using the other extreme: the low-end PC platform. We have alleviated the mismatch between this demanding application and the limited computational resources of a PC in three ways: several stages in the visualization pipeline are placed into a preprocessing step, the volume rendering algorithm was optimized using a special data compression scheme, and the algorithm has been implemented in hardware as a PCI-compatible coprocessor (lXZ,4RD). These methods give us a frame rate of up to 1OHz for 256 <sup>3</sup> data sets and an acceptable image quality, although the accelerator prototype was built using relatively slow FPGA-technology. In a low-cost environment a coprocessor must not be more expensive than the host itself, and so VIZARD was designed to be manufacturable for a few hundred dollars. The special data compression scheme allows the data set to be placed into the main memory of the PC and eliminates the need for an expensive, separate volume memory. The entire visualization system consists of a portable PC with two built-in accelerator boards. Despite its small size, the system provides perspective raycasting for realtime walk-throughs. Additional features include stereoscopic viewing using shutter glasses and volume animation.Item Iso Photographic Rendering(The Eurographics Association, 2018) Porral, Philippe; Lucas, Laurent; Muller, Thomas; Randrianandrasana, Joël; Reinhard Klein and Holly RushmeierIn the field of computer graphics, the simulation of the visual appearance of materials requires an accurate computation of the light transport equation. Consequently, material models need to take into account various factors which may influence the spectral radiance perceived by the human eye. Though numerous relevant studies on the reflectance properties of materials have been conducted to date, environment maps used to simulate visual behaviors remain chiefly trichromatic. Whereas questions regarding the accurate characterization of natural lighting have been raised for some time, there are still no real sky environment maps that include both spectral radiance and polarization data. Under these conditions the simulations carried out are approximate and therefore insufficient for the industrial world where investment-sensitive decisions are often made based on these very calculations.Item An Improved Z-Buffer CSG Rendering Algorithm(The Eurographics Association, 1998) Stewart, Nigel; Leach, Geoff; John, Sabu; S. N. SpencerWe 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.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 Parallel Texture Caching(The Eurographics Association, 1999) lgehy, Homan; Eldridge, Matthew; Hanrahan, Pat; A. Kaufmann and W. Strasser and S. Molnar and B.- O. SchneiderThe creation of high-quality images requires new functionality and higher performance in real-time graphics architectures. In terms of functionality, texture mapping has become an integral component of graphics systems, and in terms of performance, parallel techniques are used at all stages of the graphics pipeline. In rasterization, texture caching has become prevalent for reducing texture bandwidth requirements. However, parallel rasterization architectures divide work across multiple functional units, thus potentially decreasing the locality of texture references. For such architectures to scale well, it is necessary to develop efficient parallel texture caching subsystems. We quantify the effects of parallel rasterization on texture locality for a number of rasterization architectures, representing both current commercial products and proposed future architectures. A cycle-accurate simulation of the rasterization system demonstrates the parallel speedup obtained by these systems and quantities inefficiencies due to redundant work, inherent parallel load imbalance, insufftcient memory bandwidth, and resource contention. We find that parallel texture caching works well, and is general enough to work with a wide variety of rasterization architectures.Item Ray-Traced Collision Detection: Interpenetration Control and Multi-GPU Performance(The Eurographics Association, 2013) Lehericey, Francois; Gouranton, Valérie; Arnaldi, Bruno; Betty Mohler and Bruno Raffin and Hideo Saito and Oliver StaadtWe proposed in [LGA13] an iterative ray-traced collision detection algorithm (IRTCD) that exploits spatial and temporal coherency and proved to be computationally efficient but at the price of some geometrical approximations that allow more interpenetration than needed. In this paper, we present two methods to efficiently control and reduce the interpenetration without noticeable computation overhead. The first method predicts the next potentially colliding vertices. These predictions are used to make our IRTCD algorithm more robust to the above-mentioned approximations, therefore reducing the errors up to 91%. We also present a ray re-projection algorithm that improves the physical response of ray-traced collision detection algorithm. This algorithm also reduces, up to 52%, the interpenetration between objects in a virtual environment. Our last contribution shows that our algorithm, when implemented on multi-GPUs architectures, is far faster.Item VoxelCache: A Cache-Based Memory Architecture for Volume Graphics(The Eurographics Association, 2003) Kanus, U.; Wetekam, G.; Hirche, J.; M. Doggett and W. Heidrich and W. Mark and A. SchillingThis paper presents a cache-based memory architecture for volume graphics. We describe the memory organization and cache logic to implement a voxel cache based on 43 voxel blocks. We show an efficient prefetching scheme that increases the cache hit ratio to more than 98% in most cases. The performance of the memory system with different types of external memory is demonstrated by a cycle accurate C++ simulation. The VoxelCache memory architecture is designed to be easily adapted to different memory technologies, because all volume graphics specific parts of the memory system are encapsulated inside the on-chip cache. The design is targeted at implementation on off-the-shelf reconfigurable hardware.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.