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We present a new GPU-based rendering system for ray casting of multiple volumes. Our approach supports a large number of volumes, complex translucent and concave polyhedral objects as well as CSG intersections of volumes and geometry in any combination. The system (including the rasterization stage) is implemented entirely in CUDA, which allows full control of the memory hierarchy, in particular access to high bandwidth and low latency shared memory. High depth complexity, which is problematic for conventional approaches based on depth peeling, can be handled successfully. As far as we know, our approach is the first framework for multivolume rendering which provides interactive frame rates when concurrently rendering more than 50 arbitrarily overlapping volumes on current graphics hardware.

The texture evolution of cold-rolled Zircaloy-2 sheets during the alpha -> beta ->alpha phase transformation was characterized in situ using high-energy synchrotron X-ray diffraction. It was found that the strong rolling texture is initially modified during heating, evidencing recrystallization, after which it is weakened by a complete phase transformation. Hardly any variant selection was observed during alpha -> beta phase transformation. When the material was rapidly cooled back from above the beta-transus, the alpha texture exhibited moderated variant selection. In a study of the effect of maximum heating temperature on the inherited alpha texture, it was found that incomplete transformations, even with peak temperatures nearing the beta-transus, resulted in a perfect texture memory in spite of dramatic morphological changes in the microstructure. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

In real-time 3D Graphics, pipeline optimization is one of techniques enhancing rendering performance. Pipeline optimization is kind of buffer reordering problem, but it is NP-hard. Therefore techniques that is approximating optimal solution and suitable for real-time 3D graphics are needed. This paper analyze pattern of rendering states changing costs for real-time 3D graphics, and based on this, the algorithm that brings rendering states into line by changing costs is proposed. The proposed technique shows good performance enhancement when costs of some rendering states are much higher than others. Proposed technique shows 2.5 to 4 times better performance than non-ordering algorithm and becomes more faster when rendering costs of a state gets higher.

Texture compression is an important technique in graphics processing units (GPUs) for saving memory bandwidth. This paper presents a high-quality mipmapping texture compression (MTC) system with alpha maps. Based upon the wavelet transform, a hierarchical approach is adopted for mipmapping textures in the YCbCr color space and alpha channel. By inspecting the similarity between the alpha and luminance channels, the two channels are efficiently encoded together with linear prediction in the differential mode. In addition, the split mode manages textures with no strong relationship between the alpha and luminance channels. A layer overlapping technique is also proposed to reduce the texture memory bandwidth. Simulation results show that MTC can reduce the texture access traffic by 80% to 90% and provides high image quality as well. Compared with DirectX texture compression (DXTC), the most well-known texture compression with alpha maps, MTC reduces the texture access bandwidth by 30% more. VLSI implementation results show that the hardware cost of MTC is similar to that of DXTC and that MTC is suitable for integration in GPUs to provide high-quality textures with low memory bandwidth requirements.

This paper presents a technique for creating oblique view maps of urban areas. We identify and apply cartographic and cognitive principles to develop a solution in the context of state-of-art geographic information systems. The gap in the ability of these systems to render three-dimensional buildings into maps is addressed. At the core of our solution is a building facade modelling approach that supports varying degrees of abstraction. This is achieved by introducing a concept of 'facade waveforms' and representing building facades as combinations of these waveforms. A Fourier series approximation of the waveforms is used during the rendering processes resulting in an elegant solution to anti-aliasing. The formulation retains the semantic information in the representation that enables meaningful extensions like night time facade generation. The solution is implemented as a pixel shader and therefore leads to a large reduction in texture memory requirement compared with existing building rendering ...

We present a novel perceptual method to reduce the visual redundancy of unstructured lumigraphs, an image based representation designed for interactive rendering. We combine features of the unstructured lumigraph algorithm and image fidelity metrics to efficiently rank the perceptual impact of the removal of subregions of input views ( subviews ). We use a greedy approach to estimate the order in which subviews should be pruned to minimize perceptual degradation at each step. Renderings using varying numbers of subviews can then be easily visualized with confidence that the retained subviews are well chosen, thus facilitating the choice of how many to retain. The regions of the input views that are left are repacked into a texture atlas. Our method takes advantage of any scene geometry information available but only requires a very coarse approximation. We perform a user study to validate its behaviour, as well as investigate the impact of the choice of image fidelity metric as well as that of user parameters. The three metrics considered fall in the physical, statistical and perceptual categories. The overall benefit of our method is the semiautomation of the view selection process, resulting in unstructured lumigraphs that are thriftier in texture memory use and faster to render. Using the same framework, we adjust the parameters of the unstructured lumigraph algorithm to optimise it on a scene by scene basis.

We introduce a novel representation for random-access rendering of antialiased vector graphics on the GPU, along with efficient encoding and rendering algorithms. The representation supports a broad class of vector primitives, including multiple layers of semitransparent filled and stroked shapes, with quadratic outlines and color gradients. Our approach is to create a coarse lattice in which each cell contains a variable-length encoding of the graphics primitives it overlaps. These cell-specialized encodings are interpreted at runtime within a pixel shader. Advantages include localized memory access and the ability to map vector graphics onto arbitrary surfaces, or under arbitrary deformations. Most importantly, we perform both prefiltering and supersampling within a single pixel shader invocation, achieving inter-primitive antialiasing at no added memory bandwidth cost. We present an efficient encoding algorithm, and demonstrate high-quality real-time rendering of complex, real-world examples.

Image-based rendering techniques are a powerful alternative to traditional polygon-based computer graphics. This paper presents a novel light field rendering technique which performs per-pixel depth correction of rays for high-quality reconstruction. Our technique stores combined RGB and depth values in a parabolic 2D texture for every light field sample acquired at discrete positions on a uniform spherical setup. Image synthesis is implemented on the GPU as a fragment program which extracts the correct image information from adjacent cameras for each fragment by applying per-pixel depth correction of rays. We show that the presented image-based rendering technique provides a significant improvement compared to previous approaches. We explain two different rendering implementations which make use of a uniform parametrisation to minimise disparity problems and ensure full six degrees of freedom for virtual view synthesis. While one rendering algorithm implements an iterative refinement approach for rendering light fields with per pixel depth correction, the other approach employs a raycaster, which provides superior rendering quality at moderate frame rates.

This paper presents a method for the accurate rendering of path-based surface details such as grooves, scratches and similar features. The method is based on a continuous representation of the features in texture space, and the rendering is performed by means of two approaches: one for isolated or non-intersecting grooves and another for special situations like intersections or ends. The proposed solutions perform correct antialiasing and take into account visibility and inter-reflections with little computational effort and memory requirements. Compared to anisotropic BRDFs and scratch models, we have no limitations on the distribution of grooves over the surface or their geometry, thus allowing more general patterns. Compared to displacement mapping techniques, we can efficiently simulate features of all sizes without requiring additional geometry or multiple representations.

Since 2005, the production of feature 3D animation has been growing up worldwide and technology of hardware and software has been advanced fully enough to get over the limitation of visual expression, so that rendering weight of the whole work process is getting more important. A final file in the state right before rendering increases. the data size gets bigger. Therefore, if such final file is rendered as it is, the production schedule may not be met. For, some needless time shall be spent to call and save a high-capacity file in amendment work and to execute the rendering entirely again in addition to amendment. In this study, Maya API [1]was used to study the efficient information amendment method of extracting the rendering layers` files in order to develop a tool that executes rendering by applying such method. As the result, compliance to production schedule that is important in animation production can be done through the independent rendering tool based layer rendering that can maximize the efficiency of amendment work.

Cataloged from PDF version of article. High-quality computer graphics let mobile-device users access more compelling content. Still, the devices' limitations and requirements differ substantially from those of a PC. This survey of mobile graphics research describes current solutions in terms of specialized hardware (including 3D displays), rendering and transmission, visualization, and user interfaces.

In this paper, a 3D display processor embedding a programmable 3D graphics rendering engine is proposed. The proposed processor combines a 3D graphics rendering engine and a 3D image synthesis engine to support both true realism and interactivity for the future multimedia applications. Using high coherence between 3D graphics data and 3D display inputs, both pipelines are merged by sharing buffers such that a 3D display engine directly uses the output of a 3D graphics rendering engine. The merged architecture has synergetic coupling effects such as freely providing various rendering effects to 3D images and easily computing disparities without complex extraction processes. In the 3D image synthesis engine, we adopt view interpolation algorithm and propose real-time synthesis method, pixel-by-pixel process. The view interpolation algorithm reduces the number of images to be rendered, resulting in the reduction of external memory size to 64.8% compared to conventional synthesis process. The proposed pixel-by-pixel process synthesizes 3D images at 36 fps through bandwidth reduction of 26.7% and decreases internal memory size to 64.2% compared to typical image-by-image process. The 3D graphics rendering engine is programmable and supports the instruction sets of the latest 3D graphics standard APIs, Pixel Shader 3.0 and OpenGL|ES 2.0. The die contains about 1.7 M transistors, occupies 5 mm times 5 mm in 0.18 mum CMOS and dissipates 379 mW at 1.85 V.

We propose a method for rendering volumetric data sets at interactive frame rates while supporting dynamic ambient occlusion as well as an approximation to color bleeding. In contrast to ambient occlusion approaches for polygonal data, techniques for volumetric data sets have to face additional challenges, since by changing rendering parameters, such as the transfer function or the thresholding, the structure of the data set and thus the light interactions may vary drastically. Therefore, during a preprocessing step which is independent of the rendering parameters we capture light interactions for all combinations of structures extractable from a volumetric data set. In order to compute the light interactions between the different structures, we combine this preprocessed information during rendering based on the rendering parameters defined interactively by the user. Thus our method supports interactive exploration of a volumetric data set but still gives the user control over the most important rendering parameters. For instance, if the user alters the transfer function to extract different structures from a volumetric data set the light interactions between the extracted structures are captured in the rendering while still allowing interactive frame rates. Compared to known local illumination models for volume rendering our method does not introduce any substantial rendering overhead and can be integrated easily into existing volume rendering applications. In this paper we will explain our approach, discuss the implications for interactive volume rendering and present the achieved results.

Existing parallel graphics rendering systems only support single level parallel rendering pipeline. This paper presents a novel high performance parallel graphics rendering architecture on PC-Cluster supporting tiled display wall. It employs a hybrid sort-first and sort-last architecture based on a new rendering and scheduling structure, called dynamic rendering team (DRT as abbreviation), which is composed of multiple PCs instead of single PC to act as a rendering node. Each DRT responds for a certain projector area in the tiled display wall and all DRTs form a outer level parallel rendering pipeline natively. Inside separate DRT there is an optimized parallel Rendering-Composing-Display (R-C-D) pipeline reconstructing the serial workflow to parallel one. The Optimized parallel R-C-D pipeline along with the outer parallel rendering pipelines among DRTs forms a special nested parallel pipeline architecture, which promotes the whole rendering performance of our system greatly. Experiments show that parallel rendering system with the proposed architecture and nested parallel rendering pipelines, called Parallel-SG, can render over 13M triangles at an average speed of 12 frames per second without any accelerating technologies on a tile-display wall of 5*3 projectors array.

Currently 3D animation rendering and video compression are completely independent processes even if rendered frames are streamed on-the-fly within a client-server platform. In such scenario, which may involve time-varying transmission bandwidths and different display characteristics at the client side, dynamic adjustment of the rendering quality to such requirements can lead to a better use of server resources. In this work, we present a framework where the renderer and MPEG codec are coupled through a straightforward interface that provides precise motion vectors from the rendering side to the codec and perceptual error thresholds for each pixel in the opposite direction. The perceptual error thresholds take into account bandwidth-dependent quantization errors resulting from the lossy com-pression as well as image content-dependent luminance and spatial contrast masking. The availability of the discrete cosine transform (DCT) coefficients at the codec side enables to use advanced models of the human visual system (HVS) in the perceptual error threshold derivation without incurring any significant cost. Those error thresholds are then used to control the rendering quality and make it well aligned with the compressed stream quality. In our prototype system we use the lightcuts technique developed by Walter et al., which we enhance to handle dynamic image sequences, and an MPEG-2 implementation. Our results clearly demonstrate many advantages of coupling the rendering with video compression in terms of faster rendering. Furthermore, temporally coherent rendering leads to a reduction of temporal artifacts.

This paper presents a method to accelerate algorithms that need a correct and complete visibility ordering of their data for rendering. The technique works by pre-sorting primitives in object-space using three lists (one for each axis: X, Y and Z), and then combining the lists using graphics hardware by rendering each list to a texture and merging the textures in the end. We validate our algorithm by applying it to the splatting technique using several types of rendering, including point-based rendering and volume rendering. We also detail our hardware implementation for volume rendering using point sprites.

We present an efficient GPU-based implementation of the Proj ected Tetrahedra (PT) algorithm. By reducing most of the CPU‐GPU data transfer, the algorithm achieves intera ctive frame rates (up to 2.0 M Tets/s) on current graphics hardware. Since no topology information is stored , it requires substantially less memory than recent interactive ray casting approaches. The method uses a two-p ass gpu approach with two fragment shaders. This work includes extended volume inspection capabilities by s upporting interactive transfer function editing and isosurface highlighting using a Phong illumination model.

We propose a new method to accelerate rendering during the interactive visualization of complex scenes. The method is applicable if the cost of per-pixel processing is high compared to simple frame buffer transfer operations, as supported by low-end graphics systems with high-performance CPUs or 2-D graphics accelerators. In this case rendering an appropriately down-scaled image and then enlarging it allows a trade-off of rendering speed and image quality. Using this method, more uniform frame rates can be achieved and the dynamic viewing error can be reduced.

In this paper, we proposed a parallel algorithm to implement the sparse matrix transposition using ELLPACK-R format on the graphic processing units. By utilizing the tremendous memory bandwidth and the texture memory, the performance of this algorithm can be efficiently improved. Experimental results show that the performance of the proposed algorithm can be improved up to 8x times on Nvidia Tesla C2070, compared with the implementation on the Intel Xeon E5-2650 CPU. It also can be concluded that it is not wise to accelerate the transposition algorithm for the matrices in the ELLPACK-R format with violent divergence in the number of nonzero elements among the rows.

We propose a technique using geometry buffers for real-time rendering of 3D ink-wash paintings. According to the characteristics of hand-drawn ink-wash paintings, contour lines and coloring area in the ink paintings are stylized by rendering 3D models to 2D texture images. Entire rendering computation is implemented with a GPU for enabling its real-time processing on commercially available computers.

In this paper, we present an efficient resolution independent path rendering algorithm. To do so, we propose tile binning and rendering algorithm for resolution independent path rendering which is suitable to use on mobile device. Experimental comparisons show that our scheme reduces not only most of memory I/O overhead but also 50% of computation overhead. As the result, most of mobile phones can enjoy scalable high performance path rendering with our scheme.

High-strength medium-manganese steel sheets recrystallized in the alpha phase after cold-rolling have a good press formability due to the //ND texture. If the A3 temperature and the alpha-to-gamma transformation temperature are decreased, the addition of manganese affects the recrystallization and the formability. In this work, the annealing texture evolution of medium-manganese steel was investigated, carbon-free Fe-Mn sheets being used for preliminary research, and some temperatures around the T0 temperature, at which ferrite and austenite have the same free energy, were selected for annealing. It was confirmed that the To temperature is a key factor to control annealing texture, i.e., although evolving with progress of recovery and partial recrystallization at annealing temperatures below the T0, the gamma fiber ( //ND) texture disappears at temperatures above the T0. The texture memory effect during alpha-gamma-alpha transformation was not confirmed in this binary system.

In this paper we present a novel real-time cartoon-style rendering approach, which targets very large meshes. Cartoon drawing usually uses a limited number of colors for shading and emphasizes special effects, such as sharp curvature and silhouettes. It also paints the remaining large regions with uniform solid colors. Our approach quantizes light intensity to generate different shadow colors and utilizes multiresolution mesh hierarchy to maintain appropriate levels of detail across various regions of the mesh. To comply with visual requirements, our algorithm exploits graphics hardware programmability to draw smooth silhouette and color boundaries within the vertex and fragment processors. We have adopted a simplification scheme that executes simplification operators without incurring extra simplification operations as a precondition. The real-time refinement of the mesh, which is performed by the graphics processing unit (GPU), dramatically improves image quality and reduces CPU load.

In this paper we present persistent grid mapping (PGM), a novel framework for interactive view-dependent terrain rendering. Our algorithm is geared toward high utilization of modern GPUs, and takes advantage of ray tracing and mesh rendering. The algorithm maintains multiple levels of the elevation and color maps to achieve a faithful sampling of the viewed region. The rendered mesh ensures the absence of cracks and degenerate triangles that may cause the appearance of visual artifacts. In addition, an external texture memory support is provided to enable the rendering of terrains that exceed the size of texture memory. Our experimental results show that the PGM algorithm provides high quality images at steady frame rates.

Commodity graphics hardware has seen incredible growth in terms of performance, programmability, and arithmetic precision. Even though these trends have been primarily driven by the entertainment industry, the price-to-performance ratio of graphics processors (GPUs) has attracted the attention of many within the high-performance computing community. While the performance of the GPU is well suited for computational science, the programming interface, and several hardware limitations, have prevented their wide adoption. In this paper we present Scout, a data-parallel programming language for graphics processors that hides the nuances of both the underlying hardware and supporting graphics software layers. In addition to general-purpose programming constructs, the language provides extensions for scientific visualization operations that support the exploration of existing or computed data sets.

Hardware-accelerated volume rendering using the GPU is now the standard approach for real-time volume rendering, although limited graphics memory can present a problem when rendering large volume data sets. Volumetric compression in which the decompression is coupled to rendering has been shown to be an effective solution to this problem; however, most existing techniques were developed in the context of software volume rendering, and all but the simplest approaches are prohibitive in a real-time hardware-accelerated volume rendering context. In this paper we present a novel block-based transform coding scheme designed specifically with real-time volume rendering in mind, such that the decompression is fast without sacrificing compression quality. This is made possible by consolidating the inverse transform with dequantization in such a way as to allow most of the reprojection to be precomputed. Furthermore, we take advantage of the freedom afforded by off-line compression in order to optimize the encoding as much as possible while hiding this complexity from the decoder. In this context we develop a new block classification scheme which allows us to preserve perceptually important features in the compression. The result of this work is an asymmetric transform coding scheme that allows very large volumes to be compressed and then decompressed in real-time while rendering on the GPU.

The currently observed exponentially increasing size of 3D models prohibits rendering them using brute force methods. Researchers have proposed various output-sensitive rendering algorithms to overcome this challenge. This article provides an overview of this technology.

Digitally rendered radiographs (DRR) are a vital part of various medical image processing applications such as 2D/3D registration for patient pose determination in image-guided radiotherapy procedures. This paper presents a technique to accelerate DRR creation by using conventional graphics hardware for the rendering process. DRR computation itself is done by an efficient volume rendering method named wobbled splatting. For programming the graphics hardware, NVIDIAs C for Graphics (Cg) is used. The description of an algorithm used for rendering DRRs on the graphics hardware is presented, together with a benchmark comparing this technique to a CPU-based wobbled splatting program. Results show a reduction of rendering time by about 70%-90% depending on the amount of data. For instance, rendering a volume of 2x10{sup 6} voxels is feasible at an update rate of 38 Hz compared to 6 Hz on a common Intel-based PC using the graphics processing unit (GPU) of a conventional graphics adapter. In addition, wobbled splatting using graphics hardware for DRR computation provides higher resolution DRRs with comparable image quality due to special processing characteristics of the GPU. We conclude that DRR generation on common graphics hardware using the freely available Cg environment is a major step toward 2D/3D registrationmore » in clinical routine.« less

Texture changes during recrystallization and the α–β–α phase transformation in two titanium alloys were investigated in situ by time-of-flight neutron diffraction by heating in a vacuum furnace to 950 °C. In commercially pure titanium, a strong texture memory effect is observed. This effect is a direct consequence of an orientation-selective α → β transformation, favoring new orientations produced during nucleation and grain growth. The β–α transformation favors β orientations with minimal misorientations, resulting in a strong final α texture that emphasizes the grain growth component. In Ti–6Al–4V, the texture memory effect is less pronounced. The high-temperature β texture is obtained by growth of pre-existing β nuclei. In a similar way, during cooling, the growth of α domains is controlled by high-temperature α orientations inherited from the β grains with Burgers orientation relation.

Illustrative volume visualization frequently employs non-photorealistic rendering techniques to enhance important features or to suppress unwanted details. However, it is difficult to integrate multiple non-photorealistic rendering approaches into a single framework due to great differences in the individual methods and their parameters. In this paper, we present the concept of style transfer functions. Our approach enables flexible data-driven illumination which goes beyond using the transfer function to just assign colors and opacities. An image-based lighting model uses sphere maps to represent non-photorealistic rendering styles. Style transfer functions allow us to combine a multitude of different shading styles in a single rendering. We extend this concept with a technique for curvature-controlled style contours and an illustrative transparency model. Our implementation of the presented methods allows interactive generation of high-quality volumetric illustrations.

We present an image-based algorithm for interactive rendering depth-of-field effects in images with depth maps. While previously published methods for interactive depth-of-field rendering suffer from various rendering artifacts such as color bleeding and sharpened or darkened silhouettes, our algorithm achieves a significantly improved image quality by employing recently proposed GPU-based pyramid methods for image blurring and pixel disocclusion. Due to the same reason, our algorithm offers an interactive rendering performance on modern GPUs and is suitable for real-time rendering for small circles of confusion. We validate the image quality provided by our algorithm by side-by-side comparisons with results obtained by distributed ray tracing.

We describe a sort-last parallel volume rendering system based on single pass volume raycasting performed in the fragment shader unit. The architecture is aimed for displaying data sets that utilize the total distributed texture memory at interactive framerates. We use non-uniform texture bricks that are constructed and distributed by means of a kd-tree to employ object space partitioning. They are further used for implementing empty-space-skipping and a load balancing mechanism, which also makes use of the kd-tree, to increase the overall performance of the rendering system. Performance numbers are given for a mid-range GPU-cluster system consisting of eight render nodes with an Infiniband interconnection.

In Ni 3 Al the cold-rolled Goss texture changed to a complicated one after primary recrystallization and returned to the original Goss during the subsequent grain growth, which can be referred to as the texture memory effect. In this study, we examined the evolution of grain orientations during the grain growth using the electron backscatter diffraction (EBSD) method. It was found that just after the primary recrystallization most of the grains had a 40°〈1 1 1〉 rotation relationship to the Goss texture, the remaining grains being Goss and other textures. The formation of the 40°〈1 1 1〉 rotated grains can be explained by a multiple twinning mechanism. In the grain growth, the Goss grains, which were surrounded by the 40°〈1 1 1〉 rotated grains, grew preferentially due to the high mobility of the 40°〈1 1 1〉 grain boundaries, leading to the texture memory effect.

The paper presented the texture evolution during primary recrystallization and following grain growth in the heavily cold-rolled Ni3Al single crystals. It turned out that the texture evolution occurred in the two stages. First, primary recrystallization caused the drastic change of the as-rolled texture. Then, as grain growth proceeded, the texture returned to the same one as the as-rolled textures. This texture return can be designated as Texture memory effect. The mechanism of the texture memory effect was discussed based on the analysis of the orientation relationship between the as-rolled and the primary recrystallization textures.

The emergence of high performance 3D graphics cards has opened the way to PC clusters for high performance multidisplay environment. In order to exploit the rendering ability of PC clusters, we should design appropriate parallel rendering algorithms and parallel graphics library interfaces. Due to the rapid development of Direct3D, we bring forward DPGL, the Direct3D9-based parallel graphics library in D3DPR parallel rendering system, which implements Direct3D9 interfaces to support existing Direct3D9 application parallelization with no modification. Based on the parallelism analysis of Direct3D9 rendering pipeline, we briefly introduce D3DPR parallel rendering system. DPGL is the fundamental component of D3DPR. After presenting DPGL three layers architecture, we discuss the rendering resource interception and management. Finally, we describe the design and implementation of DPGL in detail, including rendering command interception layer, rendering command interpretation layer and rendering resource parallelization layer.

In case where IF steel is heat treated in gamma region, alpha -> gamma and gamma -> alpha transformation during heating and cooling, i.e. alpha -> gamma -> alpha transformation, take place during heating and cooling, respectively. The initial texture of alpha is potentially weakened due to two times transformation in general. On the contrary, the alpha -> gamma -> alpha. a transformed texture resembles the initial texture clearly under specific circumstances. Authors call this phenomenon "texture memory". A very distinct texture memory effect was found in IF steels. Lowering the gamma -> alpha transformation temperature pronounces texture memory significantly. The variant selection at grain boundary of gamma seems to play an important role. Moreover, it is considered that the initial alpha texture has to be sharp to in order to realize texture memory.

There has been a profound interest of late in the digitization and reconstruction of historical monuments. Rendering massive monument models requires a cluster of workstations because of the computational infeasibility of rendering over a single machine. Moreover, interactive rendering of these massive models in an immersive environment is only possible over a cluster of machines. In this paper, we present a design of distributed rendering system to efficiently handle models with massive textures. A server holds the skeleton of the whole model and divides the screen space balancing the rendering load among multiple clients. Each client loads only the required geometry and textures to render its sub-scene. We present a virtual texturing method for handling massive textures over the distributed rendering system. These textures are combined into a texture atlas which is split into equally sized tiles. A virtual texture is built over this atlas with each pixel representing a tile in the atlas. An efficient caching module loads only the required tiles into the memory, that are identified using the virtual texture. A fragment shader uses the virtual texture as a mapping to the physical texture in memory to generate the fragments. We demonstrate the performance of our system over a 350M triangles and 500 gigapixel textured model of Vittala temple.

In every computer graphics oriented application today, it is a common practice to texture 3D models as a way to obtain realistic material. As part of this process, mesh texturing, deformation, and visualization are all key parts of the computer graphics field. This PhD dissertation was completed in the context of these three important and related fields in computer graphics. The article presents techniques that improve on existing state-of-the-art approaches related to continuity and interpolation in texture space (texturing), object space (deformation), and screen space (rendering)

In this paper, we present a tile-based path rendering scheme that provides a fast rendering on mobile device. Because legacy path rendering schemes have memory or computing intensive work, they do not provide an enough performance (fps) on mobile device. To get an acceptable performance, we propose using tile-based approach for path rendering on mobile device. The design goal of our scheme has two folds: 1) Minimize memory I/O, 2) Minimize computation. Because our scheme effectively reduces memory I/O and computation simultaneously, we can get an acceptable high performance of path rendering on mobile device.

It is important to evaluate the complexity of images generated from computed tomography (CT) to be processed for GPU-based volume rendering. The complexity evaluation is crucial because it is closely related to the speedup issues of volume rendering in GPU platforms. To evaluate the complexity of volume images, we developed a new algorithm, called EVIC, that first sets the intensity threshold that is the average of the entire image intensity evaluated during ray casting and finally calculates the number of intensity changes each of which is larger than the evaluated threshold for each pair of samples. This algorithm is significant, because it does not take too much additional time to the original ray casting algorithm.

Volume rendering techniques have been used widely for high quality visualization of 3D datasets, especially 3D images. However, when rendering very large (out-of-core) datasets, some traditional in-core volume rendering algorithms do not work due to the impossibility of fitting the entire input data in the main memory of a computer. Their simple out-of-core versions do not perform well either because of the slow speed external memory access overhead. In order to solve this problem, a semi-adaptive partitioning strategy and an efficient out-of-core volume rendering method based on it are proposed in this paper. By this new partitioning strategy, the out-of-core dataset is divided into small sub-blocks in different sizes, which are organized by a BSP tree. Each sub-block can be loaded into the fast texture memory of the graphics hardware and be rendered by certain volume rendering algorithm based on 3D texture. Then the final result is obtained by composing the projection images of all the sub-blocks from back to front after traveling the BSP tree according to the viewpoint position. The experimental results indicate that the new method is effective and efficient for the volume visualization of out-of-core 3D images.

This paper features an advanced implementation of the X-ray rendering algorithm that harnesses the giant computing power of the current commodity graphics processors to accelerate the generation of high resolution digitally reconstructed radiographs (DRRs). The presented pipeline exploits the latest features of NVIDIA Graphics Processing Unit (GPU) architectures, mainly bindless texture objects and dynamic parallelism. The rendering throughput is substantially improved by exploiting the interoperability mechanisms between CUDA and OpenGL. The benchmarks of our optimized rendering pipeline reflect its capability of generating DRRs with resolutions of 2048(2) and 4096(2) at interactive and semi interactive frame-rates using an NVIDIA GeForce 970 GTX device.

We present an efficient technique for modeling and rendering complex surface details defined at multiple scales. Conceptually, meta-relief texture mapping can be described as recursively mapping finer relief-texture layers on top of coarser ones. Such a factorization has several desirable properties. For instance, it provides a way of simulating highly-complex surface details as a combination of simpler and inexpensive image-based representations. This greatly simplifies the modeling of surface details, enhancing the artists' expressive power. We also introduce a dynamic texture-space ambient-occlusion technique for relief mapping, which greatly improves the quality of relief renderings. We demonstrate the effectiveness of these techniques by creating and rendering a number of meta-relief textures with complex surface details which would have been hard to model directly.

Fractal Image Coding (FIC) is a lossy compression technique with promising features, however it has been relegated due to its large coding time. The present article proposes an efficient parallel implementation of FIC algorithm on a general propose computing on graphic processing unit (GPGPU) system. Two parallel implementations using different memory spaces are compared: global memory and texture memory. The experiments demostrated that texture memory achived a better acceleration factor than global memory of about 350 times.

In order to render 3-D graphics efficiently, rendering pipeline fixed function have been developed. Traditional triangle traversal techniques using edge-equation-based or scan-line-based methods may cause potential instability from the division operations. Moreover, traditional anti-aliasing techniques using the grid-based or point-sharing of edge to do super-sampling are not regular and the quality is also not good enough. This paper develops an efficient barycentric-based traversal algorithm using Ladder Start tile which is division free. Throughout the process, improved the efficiency and stability of the graphic rendering and no extra traversal position is produced to reduce the number of pixel tests. It also proposed a novel quality strategy for primitive's shared-edge sampling in antialiasing operation. The blending colors in the neighborhood of these edges according to a set of simple coverage rules, allowing area approximate, yet the fast and more robust anti-aliasing.

This paper investigates the practicality of memory attacks on commercial Graphics Processing Units (GPUs). With recent advances in the performance and viability of using GPUs for various highly-parallelised data processing tasks, a number of security challenges are raised. Unscrupulous software running subsequently on the same GPU, either by the same user, or another user, in a multi-user system, may be able to gain access to the contents of the GPU memory. This contains data from previous program executions. In certain use-cases, where the GPU is used to offload intensive parallel processing such as pattern matching for an intrusion detection system, financial systems, or cryptographic algorithms, it may be possible for the GPU memory to contain privileged data, which would ordinarily be inaccessible to an unprivileged application running on the host computer. With GPUs potentially yielding access to confidential information, existing research in the field is built upon, to investigate the practicality of extracting data from global, shared and texture memory, and retrieving this data for further analysis. These techniques are also implemented on various GPUs using three different Nvidia CUDA versions. A novel methodology for digital forensic examination of GPU memory for remanent data is then proposed, along with some suggestions and considerations towards countermeasures and anti-forensic techniques.

In this paper the virtual deferred algorithm is introduced, which combines the benefits of virtual texturing and deferred rendering in order to minimize the bandwidth consumption in rasterized based rendering. The proposed algorithm improves the performance of rendering by minimizing the number of expensive memory accesses such as texture fetches, which are usually the main catalysts for performance bottlenecks in real-time rendering. State of the art deferred rendering methods employ geometry buffers in order to avoid evaluating the lighting equation for occluded primitives. The problem with these methods is that they either fill the geometry buffers in linear complexity in texture fetches or that they draw the geometry multiple times. The proposed method almost completely decouples texture fetching from visibility determination without using multiple geometry passes. The only exceptions are geometry altering texture fetches. The virtual deferred rendering algorithm utilizes a single rasterization based rendering pass, saving only geometric information in the geometry buffer, without using any texture fetches. The algorithm then uses a compute shader and virtual texturing based rendering pipeline, which guarantees constant complexity in texture fetches without further geometry processing. The proposed method also benefits from the streaming properties of virtual texturing, making it ideal for large, streamed scenes.

Ray casting algorithm is a major component of the direct volume rendering, which exhibits inherent parallelism, making it suitable for graphics processing units (GPUs). However, blindly mapping the ray casting algorithm on a GPU's complex parallel architecture can result in a magnitude of performance loss. In this paper, a novel computation-to-core mapping strategy, called Warp Marching, for the texture-based iso-surface volume rendering is introduced. We evaluate and compare this new strategy with the most commonly used existing mapping strategy. Texture cache performance and load balancing are the two major evaluation factors since they have significant consequences on the overall rendering performance. Through a series of real-life data experiments, we conclude that the texture cache performances of these two computation-to-core mapping strategies are significantly affected by the viewing direction; and the Warp Marching performs better in balancing workloads among threads and concurrent hardware components of a GPU.

This document introduces a new application for rendering massive LiDAR point cloud data sets of interior environments within highresolution immersive VR display systems. Overall contributions are: to create an application which is able to visualize large-scale point clouds at interactive rates in immersive display environments, to develop a flexible pipeline for processing LiDAR data sets that allows display of both minimally processed and more rigorously processed point clouds, and to provide visualization mechanisms that produce accurate rendering of interior environments to better understand physical aspects of interior spaces. The work introduces three problems with producing accurate immersive rendering of Li-DAR point cloud data sets of interiors and presents solutions to these problems. Rendering performance is compared between the developed application and a previous immersive LiDAR viewer.

We propose a method to accelerate direct volume rendering using programmable graphics hardware (GPU). In the method, texture slices are grouped together to form a texture slab. Rendering non-empty slabs from front to back viewing order generates the resultant image. Considering each pixel of the image as a ray, slab silhouette maps (SSMs) are used to skip empty spaces along the ray direction per pixel basis. Additionally, SSMs contain terminated ray information. The method relies on hardware z-occlusion culling and hardware occlusion queries to accelerate ray traversals. The advantage of this method is that SSMs are created on the fly by the GPU without any pre-processing. The cost of generating the acceleration structure is very small with respect to the total rendering time.