| 1. |
- Kämpe, Viktor, 1986, et al.
(författare)
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Exploiting coherence in time-varying voxel data
- 2016
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Ingår i: Proceedings of the 20th ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games. - New York, NY, USA : ACM. - 9781450340434 ; , s. 15-21
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Konferensbidrag (refereegranskat)abstract
- We encode time-varying voxel data for efficient storage and streaming. We store the equivalent of a separate sparse voxel octree for each frame, but utilize both spatial and temporal coherence to reduce the amount of memory needed. We represent the time-varying voxel data in a single directed acyclic graph with one root per time step. In this graph, we avoid storing identical regions by keeping one unique instance and pointing to that from several parents. We further reduce the memory consumption of the graph by minimizing the number of bits per pointer and encoding the result into a dense bitstream.
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| 2. |
- Dolonius, Dan, 1985, et al.
(författare)
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Compressing color data for voxelized surface geometry
- 2017
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Ingår i: Proceedings of the 21st ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games. - New York, NY, USA : ACM. - 9781450348867 ; , s. 13:1--13:10-
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Konferensbidrag (refereegranskat)abstract
- We explore the problem of decoupling color information from geometry in large scenes of voxelized surfaces and of compressing the array of colors without introducing disturbing artifacts. First, we present a novel method for connecting each node in a sparse voxel DAG to its corresponding colors in a separate 1D array of colors, with very little additional information stored to the DAG. Then, we show that by mapping the 1D array of colors onto a 2D image using a space-filling curve, we can achieve high compression rates and good quality using conventional, modern, hardware-accelerated texture compression formats such as ASTC or BC7. We additionally explore whether this method can be used to compress voxel colors for off-line storage and network transmission using conventional off-line compression formats such as JPG and JPG2K. For real-time decompression, we suggest a novel variable bitrate block encoding that consistently outperforms previous work, often achieving two times the compression at equal quality.
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| 3. |
- Dolonius, Dan, 1985, et al.
(författare)
-
Compressing color data for voxelized surface geometry
- 2019
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1941-0506 .- 1077-2626. ; 25:2, s. 1270-1282
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Tidskriftsartikel (refereegranskat)abstract
- We explore the problem of decoupling color information from geometry in large scenes of voxelized surfaces and of compressing the array of colors without introducing disturbing artifacts. In this extension of our I3D paper with the same title [1] , we first present a novel method for connecting each node in a sparse voxel DAG to its corresponding colors in a separate 1D array of colors, with very little additional information stored to the DAG. Then, we show that by mapping the 1D array of colors onto a 2D image using a space-filling curve, we can achieve high compression rates and good quality using conventional, modern, hardware-accelerated texture compression formats such as ASTC or BC7. We additionally explore whether this method can be used to compress voxel colors for off-line storage and network transmission using conventional off-line compression formats such as JPG and JPG2K. For real-time decompression, we suggest a novel variable bitrate block encoding that consistently outperforms previous work, often achieving two times the compression at equal quality.
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| 4. |
- Kämpe, Viktor, 1986
(författare)
-
Exploiting Coherence in Voxelized Geometry
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In computer graphics, the geometry of virtual worlds can be represented in numerousways, from collections of simple triangles or voxels to higher-order primitives likecurved surfaces. There is a trade-off, both in terms of memory consumption and processingtime, between the cost of an individual primitive and the number of primitivesrequired to faithfully represent the world. This thesis focuses on decreasing the memoryconsumption of large collections of very simple voxels, while still maintaining highprocessing performance.The thesis includes three papers concerning voxel data of static geometry, shadow volumes,and time-varying geometry, respectively. A central idea in all the papers is theutilization of coherence in the data to reduce the overall size. Coherence is utilizedwhen there are many identical subvolumes. The identical subvolumes are identifiedwithout manual intervention and only a single instance of these volumes is kept, lettingseveral parents reference a single unique subvolume. The voxel data is represented withhierarchical information in a directed acyclic graph, which allows for fast traversal in,e.g., a ray tracing application.The directed acyclic graph structure is further optimized for high performance of manylocalized look-ups (like a PCF-kernel for hard shadows) and for even lower memoryfootprint when streaming time-varying geometry.
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| 5. |
- Kämpe, Viktor, 1986, et al.
(författare)
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Fast, Memory-Efficient Construction of Voxelized Shadows
- 2016
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1941-0506 .- 1077-2626. ; 22:10, s. 2239-2248
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Tidskriftsartikel (refereegranskat)abstract
- We present a fast and memory efficient algorithm for generating Compact Precomputed Voxelized Shadows. By performing much of the common sub-tree merging before identical nodes are ever created, we improve construction times by several orders of magnitude for large data structures, and require much less working memory. To further improve performance, we suggest two new algorithms with which the remaining common sub-trees can be merged. We also propose a new set of rules for resolving undefined regions, which significantly reduces the final memory footprint of the already heavily compressed data structure. Additionally, we examine the feasibility of using CPVS for many local lights and present two improvements to the original algorithm that allow us to handle hundreds of lights with high-quality, filtered shadows at real-time frame rates.
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| 6. |
- Kämpe, Viktor, 1986, et al.
(författare)
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Fast, Memory-Efficient Construction of Voxelized Shadows
- 2015
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Ingår i: Proceedings of the 19th Symposium on Interactive 3D Graphics and Games (I3D 2015). - New York, NY, USA : ACM. - 9781450333924 ; , s. 25-30
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Konferensbidrag (refereegranskat)abstract
- We present a fast and memory efficient algorithm for generatingCompact Precomputed Voxelized Shadows. By performing much ofthe common sub-tree merging before identical nodes are ever created,we improve construction times by several orders of magnitude forlarge data structures, and require much less working memory. Wealso propose a new set of rules for resolving undefined regions,which significantly reduces the final memory footprint of the alreadyheavily compressed data structure. Additionally, we examine thefeasibility of using CPVS for many local lights and present twoimprovements to the original algorithm that allow us to handlehundreds of lights with high-quality, filtered shadows at real-timeframe rates.
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| 7. |
- Kämpe, Viktor, 1986, et al.
(författare)
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High Resolution Sparse Voxel DAGs
- 2013
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 1557-7368 .- 0730-0301. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- We show that a binary voxel grid can be represented orders of magnitude more efficiently than using a sparse voxel octree (SVO) by generalising the tree to a directed acyclic graph (DAG). While the SVO allows for efficient encoding of empty regions of space, the DAG additionally allows for efficient encoding of identical regions of space, as nodes are allowed to share pointers to identical subtrees. We present an efficient bottom-up algorithm that reduces an SVO to a minimal DAG, which can be applied even in cases where the complete SVO would not fit in memory. In all tested scenes, even the highly irregular ones, the number of nodes is reduced by one to three orders of magnitude. While the DAG requires more pointers per node, the memory cost for these is quickly amortized and the memory consumption of the DAG is considerably smaller, even when compared to an ideal SVO without pointers. Meanwhile, our sparse voxel DAG requires no decompression and can be traversed very efficiently. We demonstrate this by ray tracing hard and soft shadows, ambient occlusion, and primary rays in extremely high resolution DAGs at speeds that are on par with, or even faster than, state-of-the-art voxel and triangle GPU ray tracing.
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| 8. |
- Kämpe, Viktor, 1986
(författare)
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Sparse Voxel DAGs
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates a memory-efficient representation of highly detailed geometry in 3D voxel grids. The memory consumption of a plain dense grid scales too fast as the resolution increases to be feasible at very high resolutions. In computer graphics, the geometry is often surface geometry, and representing the data in a sparse voxel octree exploits the sparsity, making the memory consumption scale much better than for a dense grid. The size of sparse voxel octrees is still significant at high resolutions, and this thesis consists of four papers addressing the memory consumption by also exploiting coherence in the data. The coherence is detected automatically in voxel data sets and encoded losslessly in a directed acyclic graph as nodes sharing descendants, as opposed to a tree where all descendants are unique. The sparse voxel DAG is used to encode hard shadows and static and time-varying opaque surface geometry, and offers just as fast access as trees, at a fraction of the memory consumption. While 1 bit per leaf node implies a lowest memory consumption of 1 bit per occupied voxel in a tree, the sparse voxel DAG repeatedly achieves much lower memory consumptions, e.g., 0.08 bits per voxel. The sparse voxel DAG is not just a single data layout for a single purpose, but a way of encoding coherence in voxel grids. The thesis shows that the limits of tree representations are not the fundamental, nor the practical, limits of how efficiently voxel grids can be represented and used, and advances the limit of grid resolutions to be considered practical in real-time rendering.
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| 9. |
- Moreau, Pierre, et al.
(författare)
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Photon Splatting Using a View-Sample Cluster Hierarchy
- 2016
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Ingår i: High-Performance Graphics 2016. - 2079-8679. - 9783038680086
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Konferensbidrag (refereegranskat)abstract
- Splatting photons onto primary view samples, rather than gathering from a photon acceleration structure, can be a more efficient approach to evaluating the photon-density estimate in interactive applications, where the number of photons is often low compared to the number of view samples. Most photon splatting approaches struggle with large photon radii or high resolutions due to overdraw and insufficient culling. In this paper, we show how dynamic real-time diffuse interreflection can be achieved by using a full 3D acceleration structure built over the view samples and then splatting photons onto the view samples by traversing this data structure. Full dynamic lighting and scenes are possible by tracing and splatting photons, and rebuilding the acceleration structure every frame. We show that the number of view-sample/photon tests can be significantly reduced and suggest further culling techniques based on the normal cone of each node in the hierarchy. Finally, we present an approximate variant of our algorithm where photon traversal is stopped at a fixed level of our hierarchy, and the incoming radiance is accumulated per node and direction, rather than per view sample. This improves performance significantly with little visible degradation of quality.
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| 10. |
- Olsson, Ola, 1976, et al.
(författare)
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Efficient Virtual Shadow Maps for Many Lights
- 2014
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Ingår i: Proceedings of the ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games (I3D 2014). - New York, NY, USA : ACM.
-
Konferensbidrag (refereegranskat)abstract
- Recently, several algorithms have been introduced that enable realtime performance for many lights in applications such as games. In this paper, we explore the use of hardware-supported virtual cubemap shadows to efficiently implement high-quality shadows from hundreds of light sources in real time and within a bounded memoryfootprint. In addition, we explore the utility of ray tracing for shadows from many lights and present a hybrid algorithm combining ray tracing with cube maps to exploit their respective strengths. Our solution supports real-time performance with hundreds of lights in fully dynamic high-detail scenes.
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