Global illumination algorithms are used to render photorealistic images of 3D scenes taking into account both direct lighting from the light source and light reflected from other surfaces in the scene. Algorithms based on computing radiosity were among the first to be used to calculate indirect lighting, although they make assumptions that work only for diffusely reflecting surfaces. The classic radiosity approach divides a scene into multiple patches and generates a linear system of equations which, when solved, gives the values for the radiosity leaving each patch. This process can require extensive calculations and is therefore very slow. An alternative to solving a large system of equations is to use a Monte Carlo method of random sampling. In this approach, a large number of rays are shot from each patch into its surroundings and the irradiance values obtained from these rays are averaged to obtain a close approximation to the real value. <br /><br /> This thesis proposes the use of a Monte Carlo method to generate radiosity texture maps on graphics hardware. By storing the radiosity values in textures, they are immediately available for rendering, making this algorithm useful for interactive implementations. We have built a framework to run this algorithm and using current graphics cards (NV6800 or higher) it is possible to execute it almost interactively for simple scenes and within relatively low times for more complex scenes.

Global illumination algorithms are used to render photorealistic images of 3D scenes taking into account both direct lighting from the light source and light reflected from other surfaces in the scene. Algorithms based on computing radiosity were among the first to be used to calculate indirect lighting, although they make assumptions that work only for diffusely reflecting surfaces. The classic radiosity approach divides a scene into multiple patches and generates a linear system of equations which, when solved, gives the values for the radiosity leaving each patch. This process can require extensive calculations and is therefore very slow. An alternative to solving a large system of equations is to use a Monte Carlo method of random sampling. In this approach, a large number of rays are shot from each patch into its surroundings and the irradiance values obtained from these rays are averaged to obtain a close approximation to the real value. <br /><br /> This thesis proposes the use of a Monte Carlo method to generate radiosity texture maps on graphics hardware. By storing the radiosity values in textures, they are immediately available for rendering, making this algorithm useful for interactive implementations. We have built a framework to run this algorithm and using current graphics cards (NV6800 or higher) it is possible to execute it almost interactively for simple scenes and within relatively low times for more complex scenes.

Vi har i detta arbete skapat ett API för widgets på Android och iOS för Visiarcs utvecklingsverktyg CoffeeMaker. CoffeeMaker använder sig av multiplattform-API:t Cocos2dx och försöker, i så stor utsträckning det är möjligt, förhålla sig till det reaktiva programmeringsparadigmet. Vi använde oss av olika designmönster för att jämna ut skillnaderna mellan Android och iOS interface och implementerade funktionalitet för knappar, checkboxes, radioknappar och textfält på dessa två plattformar. Dessa widgets tematiseras enligt ett JSON-liknande format och använder sig av en texturatlas för att spara resurser. Vi behövde en texturpackare som lämpade sig att köras under en applikations initiering och ibland även under själva körningen. Vi fann en snabb heuristik, O(n2), med god täthet, ca 94% enligt vår testmetod. / We have in this work created an widgets API on Android and iOS for Visiarcs development platform CoffeeMaker. CoffeeMaker uses the multiplattform-API Cocos2dx and tries to use the reactive programming paradigm as much as possible. We used design patterns to try to smoothen out the differences between Android and iOS and implemented functionality for buttons, checkboxes, radiobuttons and textfields on these platforms. These widgets are themeble with a JSON-like format and uses a texture atlas to be sparse on system resources. We needed a texture packer which was suited to be run during runtime of a userspace application. We found a quick heurustic, O(n2), with good density, approximately 94% according to our test method.