Orientador: Prof. Dr. Mario Alexandre Gazziro / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência da Computação, 2017. / Marmoreio em papel é um método de design principalmente utilizado por artistas desenvolvedores de capas de livros, no qual tinta a base de óleo é depositada sobre uma superfície aquosa, de forma a produzir padrões texturais semelhantes à do mármore. Os padrões são o resultado da flutuação dos pigmentos de tinta sobre a água definidos pelos movimentos manuais do artista que, em seguida, é cuidadosamente transferido para uma superfície de papel ou tecido absorvente. Apesar do fato de alguns sistemas digitais de marmoreio já terem sido desenvolvidos no passado, nenhum deles pôde fornecer simultaneamente uma interface natural ao usuário e uma simulação em tempo real. Este trabalho obteve a melhora do processo de marmoreio digital através de uma interface fácil de aprender, apresentando simultaneamente características de resposta rápida e de fácil navegação através de uma caneta digital, usando uma mesa digitalizadora como superfície de design, processando algoritmos na GPU por meio de programas shaders para os cálculos de dinâmica computacional de fluidos, envolvendo resolução em tempo real das Equações de Navier-Stokes. / Paper marbling is a design method mainly used by artists who develop book covers, in which is deposited oil-based paint on an aqueous surface in order to produce textured patterns like marble. The patterns are the result of the fluctuation of the ink pigments on the water defined by the artist¿s manual movements which is then carefully transferred to a surface o f absorbent paper or fabric. Although some digital marbling systems have already been developed in the past, none of them could simultaneously provide a natural user interface and real time simulation. This work improvement of the digital marbling process through an easy to learn interface, simultaneously presenting fast response characteristics and easy navigation through of a pen stylus, using a pen tablet as a design surface, processing GPU algorithms using shaders to calculate computational fluids dynamics, involving real time resolution of the Navier-Stokes equations.

I detta arbete utförs en jämförelse av exekveringstid för tolkning och rendering av Lindenmayersystem (L-system), utfört av samma algoritm på CPU’n (eng. central processingunit) och GPU’n (eng. graphics processing unit). Undersökningen fokuserar på exekveringstid och dess utveckling vid olika typer av L-system, längder samt upplösning. Algoritmen implementerades i spelmotorn Unity både på CPU’n via C# och på GPU’n medhjälp av beräknings-shaders. Experimenten bestod av två L-system. Ett med förgreningaroch ett utan. Båda L-systemen testades med olika upplösningar och längder, varpå exekveringstid avlästes. Experimentens resultat påvisar stor fördel hos CPU-lösningen gällande exekveringstid. Bristen på GPU-anpassad kod, exempelvis kod utan förgreningar och med bra minneshantering, leder till att GPU’n presterar sämre. Arbetet avslutas med förslag på vidareforskning. Förslagen innefattar utökad testning på olika hårdvara, en mer kontrollerad testmiljö samt implementering av algoritmen i faktisk spelproduktion.

Οι προγραμματιζόμενοι επεξεργαστές γραφικών (Graphics Processing Units - GPUs), είναι πανίσχυροι παράλληλοι επεξεργαστές και πλέον υπάρχουν σε κάθε σύγχρονο προσωπικό υπολογιστή (PC). Οι GPUs αναλαμβάνουν κι επιταχύνουν την σχεδίαση δισδιάστατων και τρισδιάστατων γραφικών στην οθόνη του υπολογιστή. Η εξέλιξή τους είναι τόσο ραγδαία τα τελευταία χρόνια, που πλέον ξεπερνούν σε πολυπλοκότητα τις σύγχρονες κεντρικές μονάδες επεξεργασίας (CPUs), ενώ είναι ικανές να επιταχύνουν εκτός από γραφικά κι άλλες απαιτητικές σε επεξεργαστική ισχύ εφαρμογές, όπως είναι η τεχνητή νοημοσύνη και η προσομοίωση φυσικών αλληλεπιδράσεων μεταξύ αντικειμένων (συγκρούσεις, εκρήξεις, προσομοίωση κίνησης υγρών) κ.α. Σκοπός της συγκεκριμένης εργασίας είναι η δημιουργία, η μελέτη και η βελτιστοποίηση αλγορίθμων σκίασης με χρήση GPUs. Ο όρος σκίαση (shading) αναφέρεται στην αλληλεπίδραση του φωτός με τα αντικείμενα ενός εικονικού περιβάλλοντος. Παρουσιάζονται τα εργαλεία (APIs) και οι γλώσσες προγραμματισμού των GPUs καθώς και τρόποι βελτιστοποίησης της εκτέλεσης των σκιάσεων που είναι ένα θέμα μείζονος σημασίας σε προσομοιώσεις πραγματικού χρόνου. / Graphics processing units (GPUs), are powerful parallel processors and today are found in every modern Personal Computer (PC). The GPUs accelerate the drawing of two and three dimensional graphics on the monitor of the PCs. The evolution of this hardware is very rapid the last decade and today these circuits are more complex than CPUs. They are capable of accelerating many demanding applications except graphics, like Artificial Intelligence and Physics Simulation. The purpose of this thesis is to implement, study and optimize the execution of shading algorithms that run on GPUs in real time. The term shading refers to the interactions between light and the material of every object in a virtual three dimensional environment. In this thesis we present the tools, the programming languages and techniques for optimizing the execution of the shaders which is a matter of major importance in real time simulations.

This work deals with design and implementation of a game based on the XNA platform. It describes the platform and its possibilities of game development for both the PC and the Xbox 360 console. The implemented game is called NanoHeal and it is about the treatment of various health problems. The work also investigates graphic techniques such as non-photorealistic rendering, the depth of field effect and particle systems. These techniques are used to achieve the distinguished look of the game. Key features of the game were evaluated in the online questionnaire.

This thesis deals with accelerated 3D rendering of medical data, e.g. computed tomography, using a graphics processor and OpenGL library. Raw data slices are send to graphic memory and rendered by a ray-casting algorithm. The goal of this project is high quality visual output and full user interaction at the same time. Multiple rendering modes are avaiable to the user: MIP, X-Ray simulation and realistic shading.

This paper concerns aliasing removal methods during the shadow displaying. Method of shadow mapping, its principles, procedure and mainly its drawbacks in the form of aliasing development are described. For the removal of this undesirable phenomenon, several aliasing suppressing methods are described - Percentage Closer Filter, Variance Shadow Map, Convulotion Shadow Map, Exponential Shadow Map a Bilateral Filter. I conclude my work with a proposal and implementation of a demonstrative application, which demonstrates the implemented results adequately. Also, the comparison of individual methods on the basis of their quality and computational demands is included.

The goal of this thesis is to investigate the possibilities of the OGRE visualization library and to implement an application which utilizes both simple and advanced OGRE features. Furhtermore there are explained basics of creating effects using Cg language and connecting them with OGRE library. The Bullet library which is often used in visualization applications for physics calculations is analyzed as well. The second part describes implementation of the demo application. In the end, the results are discussed, including possibilities of future development.

Genom att skapa shaders kan datorspelsutvecklare åstadkomma en uppsjö av visuella effekter. Det enda som sätter gränserna är fantasin och prestandan. En av de största spelmotorerna på marknaden är Unity Engine (Unity Technologies, 2005). Det finns två utvecklingsmetoder för att skapa shaders i Unity; genom det visuella verktyget Unity Shader Graph eller genom att programmera i High-Level Shading Language. Fördelen med Unity Shader Graph är dess användarvänlighet. Kan en följd av denna användarvänlighet vara en nackdel på resultatets prestanda?  Denna studies syfte är att undersöka prestandaskillnader mellan shaders implementerade med High-Level Shading Language kontra Unity Shader Graph. Detta undersöktes genom att skapa tre shaders i Unity Shader Graph och sedan tre utseendemässigt liknande shaders i High-Level Shading Language. Efter skapandet, optimerades shadersarna skapta med High-Level Shading Language genom optimeringstekniker föreslagna av Crawford och O’Boyle (2018). Resultatet visade att inga starka kopplingar kunde göras mellan användandet av Unity Shader Graph och försämrad prestanda. Testresultaten var inte konklusiva, vissa shaders presterade bättre på en hårdvara men sämre på alternativ hårdvara. Vid 3 av 6 test presterade de jämförda shadersarna utan en signifikant prestandaskillnad. / <p>Det finns övrigt digitalt material (t.ex. film-, bild- eller ljudfiler) eller modeller/artefakter tillhörande examensarbetet som ska skickas till arkivet. </p><p>There are other digital material (eg film, image or audio files) or models/artifacts that belongs to the thesis and need to be archived.</p>

Inom spelutveckling vill utvecklare gärna använda sig av visuella effekter för sina spel och genom shaderprogram kan en mångfald av visuella effekter skapas. Det som hindrar spelutvecklare från att använda sig utav alla visuella effekter de vill ha med i spelet är prestandan. Alla användare har inte tillgång till den senaste hårdvaran och kan ha minimikrav på prestandan hos ett spel. Spelbranschen går dessutom mer mot mobila spel (ISFE &amp; EGDF 2021, ss. 18-19). Mobiler har begränsade resurser och har inte lika mycket processorkraft för grafik som en dedikerad grafikprocessor kan ge. Syftet med denna studie är att undersöka om det finns en skillnad i prestanda på shaders som implementerats med Unreal Material kontra High-Level Shading Language. Detta gjordes genom en implementation i varje språk av två shadereffekter. Efteråt konstruerades två renderingsintensiva scener där tidsmätningar på varje implementation genomfördes. Resultatet av detta kunde inte visa på någon koppling mellan vilket implementationssätt som användes och skillnad i prestanda. Resultaten av testerna kunde endast peka på en försumbar skillnad i prestanda.

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