In recent years, multiresolution models have progressed substantially. At the beginning, discrete models were employed in graphics applications, due mainly to the low degree of complexity involved in implementing them, which is the reason why nowadays they are still used in applications without high graphics requirements. Nevertheless, the increase in realism in graphics applications makes it necessary to use multiresolution models which are more exact in their approximations, which do not call for high storage costs and which are faster in visualization. This has given way to continuous models, where two consecutive levels of detail only differ by a few polygons and where, additionally, the duplication of information is avoided to a considerable extent, thus improving on the spatial cost offered by most discrete models.Advances have been made in the use of new graphics primitives which minimize the data transfer between the CPU and the GPU, apart from trying to make use of the connectivity information given by a polygonal mesh. For this purpose, graphics primitives with implicit connectivity, such as triangle strips and triangle fans, have been developed. Many continuous models based on this type of primitives have been recently developed. In these last few years, graphics hardware performance has evolved outstandingly, giving rise to new techniques which allow the continuous models to accelerate even more. In this work, we have improved the interactive render of polygonal meshes. To tackle the problem, we firstly studied fundamental techniques to efficiently render polygonal meshes and we later made use of geometry simplification and level of detail techniques. Thus, we defined a multiresolution model that represents a polygonal mesh at any given resolution. This approach is able to manage continuous level-of-detail by smoothly adapting mesh resolution to the application requirements. Moreover, the model was modified to take the maximum advantage of the recent GPU features. We also created a modified version of the model for being used in deforming meshes. Finally, we developed an independent library to integrate our model in real-time applications.

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Interactively simulating visual appearance of natural objects under natural illumination is a fundamental problem in computer graphics. 3D computer games, geometry modeling, training and simulation, electronic commerce, visualization, lighting design, digital libraries, geographical information systems, economic and medical image processing are typical candidate applications. Recent advances in graphics hardware have enabled real-time rasterization of complex scenes under artificial lighting environment. Meanwhile, pre-computation based soft shadow algorithms are proven effective under low-frequency lighting environment. Under the most practical yet popular all-frequency natural lighting environment, however, real-time rendering of dynamic scenes still remains a challenging problem. In this dissertation, we propose a systematic approach to render dynamic glossy objects under the general all-frequency lighting environment. In our framework, lighting integration is reduced to two rather basic mathematical operations, efficiently computing multi-function product and product integral. The main contribution of our work is a novel mathematical representation and analysis of multi-function product and product integral in the wavelet domain. We show that, multi-function product integral in the primal is equivalent to summation of the product of basis coefficients and integral coefficients. In the dissertation, we give a novel Generalized Haar Integral Coefficient Theorem. We also present a set of efficient algorithms to compute multi-function product and product integral. In the dissertation, we demonstrate practical applications of these algorithms in the interactive rendering of dynamic glossy objects under distant time-variant all-frequency environment lighting with arbitrary view conditions. At each vertex, the shading integral is formulated as the product integral of multiple operand functions. By approximating operand functions in the wavelet domain, we demonstrate rendering dynamic glossy scenes interactively, which is orders of magnitude faster than previous work. As an important enhancement to the popular Pre-computation Based Radiance Transfer (PRT) approach, we present a novel Just-in-time Radiance Transfer (JRT) technique, and demonstrate its application in real-time realistic rendering of dynamic all-frequency shadows under general lighting environment. Our work is a significant step towards real-time rendering of arbitrary scenes under general lighting environment. It is also of great importance to general numerical analysis and signal processing.

Les ombres sont un élément fondamental pour garantir le réalisme des images de synthèses. Elles donnent des informations nécessaires pour discerner correctement le positionnement relatif des objets. Le calcul d'ombre dures exactes en temps-réel reste toutefois un problème difficile en Informatique Graphique. Les Shadow Maps sont privilégiées pour leurs excellentes performances, mais elles ne peuvent garantir un résultat exact par pixel. Les volumes d'ombre sont plus lents que les Shadow Maps mais produisent des ombres exactes en toute circonstances. Bien qu'ils aient récemment atteint un haut niveau de performances, ils restent sensibles à la complexité géométrique et sont limités à des scènes de taille modeste. Dans cette thèse, nous proposons un nouvel algorithme de rendu d'ombres dures en temps réel basé sur les volumes d'ombre qui reste rapide sur des scènes de très grande tailles. De plus, nous introduisons une nouvelle stratégie de partitionnement jusque-là inexplorée en Informatique Graphique : les arbres métriques. / Shadows are a fundamental visual effect for computer generated images. They provide essential spatial hints allowing us to correctly perceive objects positions in the scene. Despite its importance, computing pixel accurate shadows in real-time is a challenging problem in Computer Graphics. Shadow Maps are still the favored solution due to their high efficiency, but they can't always provide pixel accurate results. Shadow Volumes are slower than Shadow Maps but always garantee pixel accurate shadows. While recent works significantly improved their performance, they remain sensitive to scalability, which limits their application scope. In this thesis, we propose a new algorithm based on Shadow Volumes that remains fast even on very large scenes. Furthermore, we introduce a new partitioning strategy that is yet unexplored in Computer Graphics : the metric tree.

The master’s thesis submitted deals with realtime rendering of three-dimensional CAD data using Vulkan API. The thesis also covers possibilities of connecting the API with VRUT, complex solution for renderig developed by ŠKODA AUTO a.s. Design of such connection is presented in form of Vulkan rendering plugin for VRUT application. Performance of the designed module is compared with another rendering module, based on different rendering technologies.

[pt] Modelos CAD 3D são ferramentas utilizadas na indústria para planejamento e simulações antes da construção ou realização de tarefas. Em muitos casos, como por exemplo na indústria de óleo e gás, esses modelos podem ser massivos, ou seja, possuem informações detalhadas em larga escala no intuito de que sejam fontes de informações precisas. Para obtenção de navegação interativa nesses modelos é necessária uma combinação de hardware e software adequados. Mesmo hoje com GPUs mais modernas, a renderização direta desses modelos não é eficiente, sendo necessárias abordagens clássicas como descarte de objetos não visíveis e LOD antes de enviar os dados à GPU. Logo, para renderização em tempo real de modelos CAD massivos são necessários algoritmos e estruturas de dados escaláveis para processamento da cena de forma eficiente. O trabalho dessa tese propõe o MCAD (Massive Computer-Aided Design) Shape grammar, uma gramática expansiva que gera objetos para criar cenas 3D de modelos massivos de forma procedimental. Nos últimos anos, modelagem procedimental tem ganhado atenção para criar cenas 3D rapidamente utilizando uma representação compacta, que armazena regras de geração ao invés de representação explícita da cena. MCAD Shape grammar explora repetições e padrões presentes em modelos massivos para renderização de cenas, reduzindo o consumo de memória e processando a cena procedimentalmente de forma eficiente. Convertemos modelos reais de refinarias em MCAD Shape grammar e implementamos um renderizador para os mesmos. Os resultados mostraram que esta solução é escalável com alto desempenho, além de ser a primeira vez que modelagem procedimental é utilizada nesse domínio. / [en] 3D CAD models are tools used in the industry for planning and simulations before construction or completion of tasks. In many cases, such as in the oil and gas industry, these models can be massive, that is, they have large-scale detailed information in order to be sources of accurate information. Interactive navigation in these models requires a combination of appropriate hardware and software. Even nowadays with modern GPUs, the direct rendering of these models is not efficient, requiring classic approaches such as culling non-visible objects and LOD before sending the data to the GPU. Therefore, for real-time rendering of massive CAD models, we need scalable algorithms and data structures to efficiently process the scene. The work of this thesis proposes MCAD (Massive Computer-Aided Design) Shape grammar, an expansive grammar that procedurally generates objects to create 3D scenes of massive models. In recent years procedural modeling has drawn attention for quickly creating 3D scenes using a compact representation, which stores generation rules rather than explicit representation of the scene. MCAD Shape grammar explores repetitions and patterns present in massive models for rendering scenes, reducing memory footprint and procedurally processing the scene efficiently. We converted real refinery models into MCAD Shape grammar and implemented a renderer for them. Results showed that our solution is scalable with high performance, also it is the first time that procedural modeling is used in this domain.

The goal of master’s thesis was to demonstrate and benchmark peformance of Mantle and Vulkan APIs with different optimization methods. This thesis proposes a rendering toolkit with optimization methods based on parallel command buffer generating, persistent staging buffers mapping, minimal pipeline configuration and descriptor sets changing, device memory pre-allocating with managing and sharing between multiple resources. The result is reference implementation that could render dynamic scene with thousands of objects in real time.

This thesis discusses two different methods for creating soft shadows. Shadow volumes and shadow mapping, more accurately Variance Soft Shadow Mapping. It presents theory for these shadow algorithms as well as theory for few others which are necessary for understanding. Further it describes how to implement these methods and evaluates these implementations. Shadow volumes are based on creating additional geometry to the scene which serves for specifying region of penumbra. VSSM algorithm is a improved version of classic shadow mapping.

Master thesis is dealing with design and implementation of ray-tracing and path-tracing using IPP library. Theoretical part discusses current trends in acceleration of selected algorithms and also possibilities of parallelization. Design of ray-tracing and path-tracing algorithm and form of parallelization are described in proposal. This part also discusses implementation of adaptive sampling and importance sampling with Monte Carlo method to accelerate path-tracing algorithm. Next part is dealing with particular steps in implementation of selected rendering methods regarding IPP library. Implementation of network interface using Boost library is also discussed. At the end, implemented methods are subjected to performance and quality test. Final product of this thesis is server aplication capable of handling multiple connections which provides visualisation and client application which implements ray-tracing and path-tracing.