This report covers theory and comparison of techniques for rendering massive scale 3D geospa- tial planet data in a web browser. It also presents implementation details of a few of these tech- niques in WebGL and Javascript, using the Three.js [1] 3D library. The thesis project is part of the implementation of Unitea, a web based education platform for interactive astronomy visualizations. Unitea is a derivative of Uniview, which is a fulldome interactive simulation of the universe. A major part of this thesis is dedicated to the implementa- tion of Hierarchical Level of Detail (HLOD) modules for Three.js based on the theory presented by T. Ulrich [2] and later generalized by Cozzi and Ring [3]. HLOD techniques are dynamic level of detail algorithms that represent the surface of objects as accurately as possible from a certain viewing angle. By using space partitioning tree-structures, view based error metrics and culling techniques detailed representations of the objects (in this case planets) can be efficiently rendered in real-time. The modules developed provide a general-purpose library for rendering planets (or other spher- ical objects) with dynamic level of detail in Three.js. The library also features connections to online web map services (WMS) and tile services.

La synthèse d'images, qui consiste à développer des algorithmes pour générer des images à l'aide d'un ordinateur, est devenue incontournable dans de nombreuses disciplines. <p><p>Les méthodes d'affichage interactives permettent à l'utilisateur d'explorer des environnements virtuels en réalisant l'affichage des images à une cadence suffisamment élevée pour donner une impression de continuité et d'immersion. Malgré les progrès réalisés par le matériel, de nouveaux besoins supplantent toujours les capacités de traitement, et des techniques d'accélération sont nécessaires pour parvenir à maintenir une cadence d'affichage suffisante. Ce travail s'inscrit précisemment dans ce cadre. Il est consacré à la problématique de l'élimination efficace des objets masqués, en vue d'accélérer l'affichage de scènes complexes. Nous nous sommes plus particulièrement intéressé aux méthodes de précalcul, qui effectuent les calculs coûteux de visibilité durant une phase de prétraitement et les réutilisent lors de la phase de navigation interactive. Les méthodes permettant un précalcul complet et exact sont encore hors de portée à l'heure actuelle, c'est pourquoi des techniques approchées leur sont préférée en pratique. Nous proposons trois méthodes de ce type.<p><p>La première, présentée dans le chapitre 4, est un algorithme permettant de déterminer de manière exacte si deux polygones convexes sont mutuellement visibles, lorsque des écrans sont placés entre eux. Nos contributions principales ont été de simplifier cette requête, tant du point de vue théorique que du point de vue de l'implémentation, ainsi que d'accélérer son temps moyen d'exécution à l'aide d'un ensemble de techniques d'optimisation. Il en résulte un algorithme considérablement plus simple à mettre en oeuvre que les algorithmes exacts existant dans la littérature. Nous montrons qu'il est également beaucoup plus efficace que ces derniers en termes de temps de calcul.<p><p><p>La seconde méthode, présentée dans le chapitre 5, est une approche originale pour encoder l'information de visibilité, qui consiste à stocker l'ombre que générerait chaque objet de la scène s'il était remplacé par une source lumineuse. Nous présentons une analyse des avantages et des inconvénients de cette nouvelle représentation. <p><p>Finalement, nous proposons dans le chapitre 6 une méthode de calcul de visibilité adaptée aux scènes d'intérieur. Dans ce type d'environnements, les graphes cellules-portails sont très répandus pour l'élimination des objets masqués, en raison de leur faible coût mémoire et de leur grande efficacité. Nous reformulons le problème de la génération de ces graphes en termes de segmentation d'images, et adaptons un algorithme classique, appelé «watershed», pour les obtenir de manière automatique. Nous montrons que la décomposition calculée de la sorte est proche de la décomposition classique, et qu'elle peut être utilisée pour l'élimination des objets masqués.<p> / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

The emergence of digital capture devices have enabled the developmentof 3D acquisition to scan the properties of a real object : its shape and itsappearance. This process provides a dense and accurate representation of realobjects and allows to avoid the costly process of physical simulation to modelan object. Thus, the issues have evolved and are no longer focus on modelingthe characteristics of a real object only but on the treatment of data fromacquisition to integrate a copy of reality in a process of image synthesis. In this thesis, we propose new representations for appearance functions from the acquisition with the aim of defining a set of multicale models of low complexity in size working in real time on the today's graphics hardware / L'émergence des périphériques de capture numériques ont permis le développement de l'acquisition 3D pour numériser les propriétés d'un objet réel : sa forme et son apparence. Ce processus fournit une représentation dense et précise d'objets réels et permet de s'abstraire d'un processus des imulation physique coûteux pour modéliser un objet. Ainsi, les problématiquesont évolué et portent non plus uniquement sur la modélisation descaractéristiques d'un objet réel mais sur les traitements de données issues de l'acquisition pour intégrer une copie de la réalité dans un processus de synthèse d'images. Dans ces travaux de thèse, nous proposons de nouvelles représentations pour les fonctions d'apparence issues de l'acquisition dont le but est de définir un ensemble de modèles multi-échelles, de faible complexité en taille, capable d'e^tre visualisé en temps réel sur le matériel graphique actuel.

[pt] Os avanços recentes na tecnologia de simulação paralela de reservatórios de petróleo têm permitido a simulação numérica de domínios cada vez mais discretizados. Essas simulações produzem um volume de dados sem precedentes, que precisam ser visualizados em ambientes 3D, possibilitando assim a análise e inspeção cuidadosa do modelo. Tais modelos tornam as técnicas convencionais de visualização inviáveis, criando a necessidade de se desenvolver soluções escaláveis de visualização. A necessidade de se visualizar dados tão complexos introduz diversos problemas computacionais que precisam ser tratados para visualizar o modelo com taxas de renderização interativas, como a impossibilidade de armazenar o dado todo em memória principal. Existem duas linhas principais para o tratamento de modelos de tal magnitude: renderização distribuída e técnicas de multi-resolução. Nesse trabalho são propostas soluções para a visualização de modelos massivos de reservatório de petróleo em cada uma dessas frentes de pesquisa, e é feita uma discussão acerca das vantagens e limitações de cada solução. Na primeira parte do trabalho, é proposto um sistema distribuído com ordenação no fim para a renderização de tais modelos em agrupamentos de PCs, onde cada PC é equipado com múltiplas GPUs. Dado o uso eficiente de cada GPU e de um estágio de composição parcial, nossa proposta trata dos problemas de escalabilidade que surgem em todo sistema com ordenação no fim em clusters de médio a grande porte. Na segunda parte do trabalho, é proposta uma estrutura hierárquica de multi-resolução de malhas de reservatórios de petróleo, com um novo algoritmo de simplificação feito especificamente para tais malhas. A estrutura hierárquica traz novidades em relação a trabalhos relacionados, fazendo uma estimativa de erro projetado menos conservadora. É feita uma proposta para a renderização com multi-resolução com garantia de uma taxa mínima de renderização, que é o objetivo principal de tais sistemas. Além disso, é feita uma proposta para odesenho do wireframe e das propriedades associadas à malha original do modelo de reservatório mapeados sobre as malhas simplificadas, o que torna a estrutura de multi-resolução independente das propriedades geradas pela simulação, garantindo o seu reuso ao longo de múltiplas simulações do mesmo modelo. Nossos experimentos computacionais demonstram a eficiência das soluções propostas. / [en] Recent advances in parallel architectures for the numerical simulation of natural black oil reservoirs have allowed the simulation of very discretized domains. As a consequence, these simulations produce an unprecedented volume of data, which must be visualized in 3D environments for careful analysis and inspection of the model. Conventional scientific visualization techniques of such very large models are not viable, creating a demand for the development of scalable visualization solutions. The need for the visualization of such complex data introduces several computational issues which must be addressed in order to achieve interactive rendering rates, such as the impossibility of storing the entire data in main memory. There are two main research areas which propose solutions for the visualization of models with such magnitude: distributed rendering and multi-resolution techniques. This work proposes solutions for the visualization of massively complex reservoir models in each of these research areas, and a discussion over the advantages and limitations of each solution is made. In the first part of the work, we propose a distributed system based on a sort-last approach for the rendering of such models in PC clusters, where each PC is equipped with multiple GPUs. Given an efficient use of the available GPUs, combined with a pipelined implementation and the use of partial image compositions on the cluster nodes, our proposal tackles the scalability issues that arise when using mid-to-large GPU clusters. The second part of the work brings the proposal of a hierarchical multi-resolution structure of black oil reservoir meshes, with a new simplification algorithm designed specifically for such meshes. The hierarchical structure brings some new approaches in relation to related work, doing a much less conservative projected error estimation. We propose a minimum refresh rate guarantee strategy for our multiresolution rendering, which is the main goal for such systems. Afterwards, we introduce a proposal for the rendering of data associated with the original reservoir mesh mapped over the simplified meshes, such as the original model grid wireframe and reservoir properties. This proposal guarantees an independence between the multi-resolution structure and the properties generated by a simulation, which guarantees the reuse of the structure among several simulations of the same model. Experimental results demonstrate the effectiveness of the proposed solutions.

Master‘s thesis covers use of graphical user interface in audio plug-ins. In first part structure and rendering techniques of audio plug-ins graphical libraries are described. Their efficiency and their way of memory utilization is questioned. Next part puts these techniques in comparison with the state of the art methods used in computer graphics and gaming industry. Their possible use in audio graphical interafaces is analyzed. In the following part, thesis finds solutions to uneffective methods in frequently used situations by presenting deferred shading into audio parameter editor with the goal of photorealistic rendering. Second introduced technique of „Knob Normal Maps“ reduces number of images needed for rendering of turning knob from hundereds to six with comparable results. Goal of diploma thesis was to create graphical library. Graphical library with name RealBox was created, and introduced techniques are the core features. Library reduces work needed to achieve graphical user interfaces for 2D and 3D cases of use. Full class and method documentation for RealBox library was assembled. Library was tested during creation of three VST plugins, with different approaches and emphasis on quick work and fine rendering. Graphical library offers new, faster way of creating audio plug-in interfaces.

This thesis deals with the development of benchmark application for the OpenGL ES 3.0 devices using the realistic real-time rendering of 3D scenes. The first part covers the history and new features of the OpenGL ES 3.0 graphics library. Next part briefly describes selected algorithms for the realistic real-time rendering of 3D scenes which can be implemented using the new features of the discussed library. The design of benchmark application is covered next, including the design of online result database containing detailed device specifications. The last part covers implementation on Android and Windows platforms and the testing on mobile devices after publishing the application on Google Play. Finally, the results and possibilites of further development are discussed.

This master's thesis deals with the problem of real-time rendering of computer graphics using the method of frameless rendering} as counterpart to the traditional way, which is based on switching between two output buffers. Frameless rendering method is defined and studied in greater depth and its adaptive variant, which delivers better output quality without a~significant reduction of latency, is described in detail. In addition, this thesis describes the implementation of the application which has been developed to demonstrate the principle and functionality of the frameless rendering on the selected scenes. It also includes evaluation of performed tests focused to the output quality.

The aim of this thesis was to implement a software that would be able to render, simulate and record a scene with walking pedestrians in real-time, with emphasis on rendering level of realism. The output of the application could serve as an input test data for people counting systems or similar systems for video recognition. The problem was divided into three major subproblems: character animation, artificial intelligence for character movement and advanced rendering techniques. The character animation problem is solved by the skeletal animation of the model. To achieve the characters moving in a scene autonomously path finding(A* algorithm) and group behaviors(steering behaviors) were implemented. Realism in a scene is added by implemented methods such as normal-mapping, variance shadow-mapping, deffered rendering, skydome, lens flare effect and screen space ambient occlusion. Optimaliaztion of the rendering was implemented using octree data structure for space partitioning. Rendering stage of a scene can be easily parametrized through implemented GUI. Implemented application provides the user with easy way of setting a scene with walking pedestrians, setting its visualization and to record the result.

Depth of field is a naturally occurring effect in lenses describing the distance between theclosest and furthest object that appears in focus. The effect is commonly used in film andphotography to direct a viewers focus, give a scene more complexity, or to improve aes-thetics. In computer graphics, the same effect is possible, but since there are no naturaloccurrences of lenses in the virtual world, other ways are needed to achieve it. There aremany different approaches to simulate depth of field, but not all are suited for real-time usein computer games. In this thesis, multiple methods are explored and compared to achievedepth of field in real-time with a focus on computer games. The aspect of bokeh is alsocrucial when considering depth of field, so during the thesis, a method to simulate a bokeheffect similar to reality is explored. Three different methods based on the same approachwas implemented to research this subject, and their time and memory complexity weremeasured. A questionnaire was performed to measure the quality of the different meth-ods. The result is three similar methods, but with noticeable differences in both quality andperformance. The results give the reader an overview of different methods and directionsfor implementing it on their own, based on which requirements suits them.

L'imagerie moderne générée par ordinateur cherche constamment à être de plus en plus représentative de la réalité physique tout autour de nous, et un de ces phénomènes clés est la notion d'effets de distribution. Les effets de distribution sont une catégorie de comportements du transport de la lumière caractérisés par leur nature distribuée selon une ou plusieurs dimension(s) donnée(s). Par exemple, le flou de mouvement est un effet de distribution dans le temps, alors que la profondeur de champ introduit le diaphragme de la caméra, ajoutant ainsi deux dimensions. Ces effets sont communs dans les films et la réalité, les rendant donc désirables à reproduire. Dans cette thèse par articles, nous présentons quatre articles qui utilisent, étendent ou s'inspirent des effets de distribution. Premièrement, nous proposons une technique novatrice pour faire le rendu de flou de mouvement non-linéaire pour des applications en temps réel tout en conservant des caractéristiques clés d'efficacité et de mise à l'échelle. Nous tirons avantage des courbes de Bézier pour concevoir une approximation de mouvement non-linéaire depuis seulement quelques images clés et rastérisons une géométrie synthétisée pour reproduire le mouvement. Deuxièmement, nous présentons un algorithme qui fait le rendu de matériaux scintillants à haute fréquence illuminés par de grandes cartes environnementales. En utilisant une combinaison d'un système d'histogrammes de mi-vecteurs compact et des harmoniques sphériques multi échelle, nous pouvons efficacement représenter des normales de surface denses et rendre leurs interactions avec des sources de lumière filtrées de grandes dimensions. Troisièmement, nous introduisons une nouvelle méthode pour faire le rendu de dispersion sous la surface en tirant avantage de l'analyse fréquentielle et du parcours d'un arbre dual. En calculant le transport de la lumière sous la surface en espace image, nous pouvons rapidement analyser la fréquence du signal et déterminer des bandes passantes efficaces que nous pouvons alors utiliser pour limiter notre traversée dans un arbre dual d'ombrage et d'illumination. Finalement, nous démontrons un algorithme novateur d'illumination globale diffuse en temps réel qui utilise des sondes d'irradiance dynamiques. Grâce à des mises à jour efficaces de distribution de radiance, nous pouvons mettre à jour des sondes d'irradiance pendant l'exécution, prenant en compte les objets dynamiques et une illumination changeante, et nous le combinons avec une requête d'irradiance filtrée plus robuste, rendant une grille de sondes d'irradiance dense traitable en temps réel avec des artefacts minimes. / Modern computer generated imagery strives to be ever more faithful to the physical reality around us, and one such key physical phenomenon is the notion of distribution effects. Distribution effects are a category of light transport behaviors characterized by their distributed nature across some given dimension(s). For instance, motion blur is a distribution effect across time, while depth of field introduces a physical aperture for the camera, thus adding two more dimensions. These effects are commonplace in film and real life, thus making them desirable to reproduce. In this manuscript-based thesis, we present four papers which leverage, extend or inspire themselves from distribution effects. First, we propose a novel technique to render non-linear motion blur for real-time applications while conserving important scalability and efficiency characteristics. We leverage Bézier curves to approximate non-linear motion from just a few keyframes and rasterize synthesized geometry to replicate motion. Second, we present an algorithm to render glinty high-frequency materials illuminated by large environment maps. Using a combination of a compact half-vector histogram scheme and multiscale spherical harmonics, we can efficiently represent dense surface normals and render their interaction with large, filtered light sources. Third, we introduce a new method for rendering subsurface scattering by taking advantage of frequency analysis and dual-tree traversal. Computing screen-space subsurface light transport, we can quickly analyze signal frequency and determine efficient bandwidths which we then use to limit our traversal through a shading/illumination dual-tree. Finally, we show a novel real-time diffuse global illumination scheme using dynamically updated irradiance probes. Thanks to efficient spherical radiance distribution updates, we can update irradiance probes at runtime, taking into consideration dynamic objects and changing lighting, and combine it with a more robust filtered irradiance query, making dense irradiance probe grids tractable in real-time with minimal artifacts.