The purpose of this study was to investigate the suitability of using the OpenGL and OpenCL graphics application programming interfaces (APIs), to increase the speed at which 2D vector geographic information could be rendered. The research focused on rendering APIs available to the Windows operating system. In order to determine the suitability of OpenGL for efficiently rendering geographic data, this dissertation looked at how software and hardware based rendering performed. The results were then compared to that of the different rendering APIs. In order to collect the data necessary to achieve this; an in-depth study of geographic information systems (GIS), geographic coordinate systems, OpenGL and OpenCL was conducted. A simplistic 2D geographic rendering engine was then constructed using a number of graphic APIs which included GDI, GDI+, DirectX, OpenGL and the Direct2D API. The purpose of the developed rendering engine was to provide a tool on which to perform a number of rendering experiments. A large dataset was then rendered via each of the implementations. The processing times as well as image quality were recorded and analysed. This research investigated the potential issues such as acquiring data to be rendered for the API as fast as possible. This was needed to ensure saturation at the API level. Other aspects such as difficulty of implementation as well as implementation differences were examined. Additionally, leveraging the OpenCL API in conjunction with the TopoJSON storage format as a means of data compression was investigated. Compression is beneficial in that to get optimal rendering performance from OpenGL, the graphic data to be rendered needs to reside in the graphics processing unit (GPU) memory bank. More data in GPU memory in turn theoretically provides faster rendering times. The aim was to utilise the extra processing power of the GPU to decode the data and then pass it to the OpenGL API for rendering and display. This was achievable via OpenGL/OpenCL context sharing. The results of the research showed that on average, the OpenGL API provided a significant speedup of between nine and fifteen times that of GDI and GDI+. This means a faster and more performant rendering engine could be built with OpenGL at its core. Additional experiments show that the OpenGL API performed faster than GDI and GDI+ even when a dedicated graphics device is not present. A challenge early in the experiments was related to the supply of data to the graphic API. Disk access is orders of magnitude slower than the rest of the computer system. As such, in order to saturate the different graphics APIs, data had to be loaded into main memory. Using the TopoJSON storage format yielded decent data compression allowing a larger amount of data to be stored on the GPU. However, in an initial experiment, it took longer to process the TopoJSON file into a flat structure that could be utilised by OpenGL than to simply use the actual created objects, process them on the central processing unit (CPU) and then upload them directly to OpenGL. It is left as future work to develop a more efficient algorithm for converting from TopoJSON format to a format that OpenCL can utilise. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Geography, Geoinformatics and Meteorology / MSc / Unrestricted

Realistic models of landscapes are frequently needed for 3D renderings, VFX work or video games. However, modelling landscapes can be a complicated and labour-intensive task, and for this reason many algorithms have been proposed to automate the process. Among the many possible ways to create a synthetic landscape, the most common one is to simulate the various types of erosions (e.g. erosion caused by glaciers and rivers) that create real eroded landscapes, like the Grand Canyon. Many solutions have been published to simulate such terrain erosion processes in computer graphics. However the authors usually only focus on recreating a landscape at geometry level, and ignore the shading level. But surface colours and textures that match the coarse geometric features created by the erosion simulation are also essential ingredients for a believable result. And obtaining detailed surface textures by running a simulation that is able to catch all the micro-details involved is usually technically infeasible due to the involved complexity. The method that we propose attempts to get around this barrier by applying suitable detail shaders to the results of a coarse-grid erosion simulation. Specifically, we will work with a dictionary of pre-generated shaders for landscape appearance: these will be both "plain" colour...

Detta är ett arbete som undersökte en arbetsmetod för att på ett så enkelt sätt som möjligt kunna göra en visualisering av projekterade järnvägsfiler. Detta gör man för att kunder och andra personer/verksamheter ska få en bra uppfattning om hur slutprojektet kommer att se ut.

Background. Ray marching is a technique that can be used to render images of infinite terrains defined by a height field by sampling consecutive points along a ray until the terrain surface is intersected. However, this technique can be expensive, and does not generate a mesh representation, which may be useful in certain use cases. Objectives. The aim of the thesis is to implement an algorithm for view-dependent triangulation of infinite terrains in real-time without making use of any preprocessed data, and compare the performance and visual quality of the implementation with that of a ray marched solution. Methods. Performance metrics for both implementations are gathered and compared. Rendered images from both methods are compared using an image quality assessment algorithm. Results. In all tests performed, the proposed method performs better in terms of frame rate than a ray marched version. The visual similarity between the two methods highly depend on the quality setting of the triangulation. Conclusions. The proposed method can perform better than a ray marched version, but is more reliant on CPU processing, and can suffer from visual popping artifacts as the terrain is refined.

Bakgrund. Kostnaden att ljussätta en pixel blir dyrare med realistiska spel. Upplösningen av spel är ökas i samma tak för att visa upp detaljerna. Att rendera en blidruta för användare blir därför allt dyrare. Dynamic Resolution Rendering är ett sätt att enhetligt minska upplösningen för att öka prestandan fast med den nyligen släppta variable rate shading finns det nya sätt att öka prestandan men med mindre påverkan på bildkvalitén.Syfte. Målet är att se om adaptiv ljussätningsning via Variable Rate Shading kan tillåta liknande eller bättre resultat, med hänsyn på prestanda och bildkvalité, jämfört med den enhetliga ljussättningen av Dynamic Resolution Rendering. Metod. Denna undersökning kommer att utföras genom att implementera Variable Rate Shading och Dynamic Resolution Rendering i en Deferred Renderer. Prestandan kommer att mätas genom att ta tid för ljussättningspasset och bildkvalitén kommer att mätas genom att jämföra den slutgiltiga bildrutan av båda teknikerna mot den ursprunliga upplösningen via SSIM. Resultat. Övergripande visade Variable Rate Shading jämförelsebar prestanda när den applicerades på Deferred Lighting passet fast hade bildkvalité som liknande mer den originalupplösningen. Slutsatser. Variable Rate Shading visade sig vara jämförbar i prestandan som i jämförelse med dynamic resolution rendering, fast gav bättre möjlighet att bibehålla bildkvalitén. / Background. The shading cost of a pixel is only getting more expensive with more realistic games. Resolution of games is equally pushed to display the all the details in a scene. This causes rendering a frame to be very expensive. Dynamic Resolution Rendering has been used to uniformly decreases resolution to gain performance but with the new release of image-based shading through Variable Rate Shading could be the new way to gain performance with less impact on image quality. Objectives. The goal is to see if the adaptive shading possibilities of Variable Rate Shading can show equal or better results, in regards to performance and image quality, compared to the uniform shading of Dynamic Resolution Rendering. Methods. This investigation is performed by implementing them into the Deferred Lighting pass in a Deferred Renderer. The performance is measured by the render pass time of the Deferred Lighting and the image quality is measured by comparing the final frames of Variable Rate Shading and Dynamic Resolution Rendering against the original resolution through SSIM. Results. Overall Variable Rate Shading show comparable performance results to Dynamic Resolution Rendering but the image quality is closer to the original resolution. Conclusions. Using image-based shading on the deferred lighting pass allow the possibility of extracting similar performance gains as dynamic resolution rendering but allows maintaining higher image quality.

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Graphical rendering has use cases in many fields. When rendering in real time, such as in simulations or games, the time to compute each frame is of high importance. An important factor to reducing frame time is decreasing the amount of calls between the processor and graphics card. This is especially important when rendering a large amount of meshes, which is a collection of vertices representing some geometry. Two ways of achieving this are Batch and Instance rendering. This thesis aims to analyze and provide valuable insight into the factors that influence the decision between the techniques for static geometry, which is geometry that does not move. More specifically the thesis will investigate how vertex and mesh count affects the frame time. Both techniques were implemented using C++ and OpenGL and then compared against each other. The results showed that for low vertex amounts Batch rendering has lower frame time. Subsequently, at higher vertex amounts Instance rendering has lower frame time. The exact cut off depends on hardware, but in general the conclusion was that Batch rendering is better for simpler meshes while Instance rendering is better for more complex meshes. / Grafisk rendering är användbart inom många områden. När rendering sker i realtid, som i simulationer eller spel, har frame time vilket är tiden det tar att beräkna varje bildruta stor betydelse. En viktig faktor för att minska frame time är att minska antalet anrop mellan processorn och grafikkortet. Detta är särskilt viktigt vid rendering av en stor mängd meshes, vilket är en samling av noder som representerar geometri. Två sätt att uppnå detta är Batch och Instance rendering. Denna avhandling syftar till att analysera och ge värdefulla insikter i de faktorer som påverkar beslutet mellan teknikerna för statisk geometri, vilket är geometri som inte rör sig. Mer specifikt kommer avhandlingen att undersöka hur antalet noder och meshes påverkar frame time. Båda teknikerna implementerades med hjälp av C++ och OpenGL och jämfördes sedan med varandra. Resultaten visade att för låga antal noder har Batch-rendering kortare frame time. Däremot, vid högre antal noder har Instance rendering kortare frame time. Den exakta gränsen beror på hårdvaran, men den generella slutsatsen var att Batch-rendering är bättre för enklare meshes medan Instance rendering är bättre för mer komplexa meshes.

Much research has been done in creating non-photorealistic renderings of objects that mimic the look of hand-made drawings by traditional artists. This thesis extends work in this area by presenting an NPR hatching method that can be applied to 3D animated films to help them feel more hand drawn. In contrast to most other NPR methods, this method preserves the 3D lighting and effects of the film that make it interesting to watch. This process includes a procedural algorithm to create a hatching pattern that can be easily integrated into any film's pipeline that uses Renderman. In addition, we create a set of controls to adjust the hatching that are easy to use and allow our style to be applied to many different objects in many shots of a film in an efficient manner. To show the success of our method, we will discuss the implementation and results of applying it to an actual 3D animated short film.

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