This report studies impostor rendering for use with the virtual reality head mounted display Oculus Rift. The technique is replacing 3D models with 2D versions to speed up rendering, in a 3D engine. It documents the process of developing a prototype in C++ and DirectX11 and the required research needed to complete the assignment. Included in this report are also the steps involved in getting Oculus Rift support to work in a custom 3D engine and measuring the impact of impostor rendering when rendering to two screens of the head mounted display. The goal was to find the maximum models the engine could draw, while keeping the frame rate locked at 60 frames per second. 2 testers at Nordicstation came to the conclusion that 40-50 meters was the optimal distance for impostor rendering. Any closer and the flatness was noticeable. The results showed a clear improvement in frame rate when rendering a graphically intensive scene. The end result showed that the goal could be achieved at a maximum of 3000 trees with 1000 leaves. Impostor rendering was deemed effective when drawing beyond 500 trees at a time. Less than that and the technique was not needed to achieve 60 frames per second. / Denna rapport undersöker renderingstekniken impostors när den används i en simpel 3D motor tillsammans med virtuella verklighetshjälmen Oculus Rift. Impostors betyder på engelska bedragare och tekniken går ut på att den byter ut avancerade 3D modeller mot simpla 2D versioner när de är ett visst avstånd ifrån användarens virtuella kamera. Om den är korrekt implementerad ska användaren inte märka att vissa modeller är platta och tekniken sparar på resurser då grafikmotorn inte behöver rita ut alla modeller. Rapporten går igenom vad som undersöktes i förundersökningen för att kunna utveckla en prototyp med utvecklingspråket C++ och DirectX 11. I rapporten står även hur prototypen utvecklades och hur stöd för Oculus Rift lades till. De slutliga resultaten visade att impostors hade en stor påverkan på uppdateringshastigheten när antalet 3D modeller som skulle ritas var många, annars hade tekniken ingen påverkan för att nå 60 bilder per sekund. 2 testare från Nordicstation kom fram till att ett avstånd på 40-50 meter från spelarens kamera till utritning av impostors var lämplig, för att dölja att de endast är platta versioner av 3d modeller. Testet visade att motorn kunde rita ut 3000 träd, med 1000 löv på varje, och hålla 60 bilder per sekund, vilket var målet. Detta på ett avstånd av 40m på impostors. Impostorrendering var effektiv när man ritade ut fler än 500 träd åt gången. Mindre antal gav ingen märkbar effekt på testdatorn som användes för testet.

Context. Ray tracing has always been a simple but effective way to create a photorealistic scene but at a greater cost when expanding the scene. Recent improvements in GPU and CPU hardware have made ray tracing faster, making more complex scenes possible with the same amount of time needed to process the scene. Despite the improvements in hardware ray tracing is still rarely run at a interactive speed. Objectives. The aim of this experiment was to implement a new kdtree generation algorithm using DirectX 11 compute shaders. Methods. The implementation created during the experiment was tested using two platforms and five scenarios where the generation time for the kd-tree was measured in milliseconds. The results where compared to a sequential implementation running on the CPU. Results. In the end the kd-tree generation algorithm implemented did not run within our definition of real-time. Comparing the generation times from the implementations shows that there is a speedup for the GPU implementation compared to our CPU implementation, it also shows linear scaling for the generation time as the number of triangles in the scene increase. Conclusions. Noticeable limitations encountered during the experiment was that the handling of dynamic structures and sorting of arrays are limited which forced us to use less memory efficient solutions.

With each computer game generation there is always a demand for more visually pleasing environments. This pushes game developers to create more powerful rendering techniques and game artists to create more detailed art. With a visually stunning backdrop also comes the need for high-resolution models. A common issue is that if all models in a scene are high-resolution it would not only require immensely powerful hardware, it would also be wasteful as only the models in the foreground are close enough that we would recognize the increased details. The common solution to this problem has been to load several versions of each model containing varying amounts of detail. However this solution has the drawback that it increases our memory footprints as more models are loaded into the memory. Tessellation offers a more dynamic solution to the problem as it only requires us to load a low-resolution model and higher resolution versions can be generated during run-time on the GPU. With the introduction of DirectX 11 tessellation is now supported in the hardware, however we are still a few years away from seeing DirectX 11 being used as the core of any 3D rendering engine. In a transitional period like this between hardware generations game developers has to tackle the dilemma that the current hardware generation has to be supported when creating games that will also utilize the next generation. This thesis focuses on comparing the performance of a tessellation scheme supported by the current hardware generation, DirectX 10, as opposed to a scheme developed for the next generation, DirectX 11. Two prototypes, one using the Geometry shader that was introduced in DirectX 10 and the other using the fixed function tessellator introduced in DirectX 11, were built to compare the performance of tessellated model rendering. Several different variants of each prototype were tested and the general conclusion is that the tessellator performed better than the Geometry shader.

Spel idag kräver en enorm mängd arbetstimmar för att skapas, därför behövs alltid sätt att spara tid och automatisera processer. Algoritmer för polygoniseringen av skalärfält, som Marching Cubes, har under de senaste åren blivit ett allt vanligare tillvägagångssätt för att automatiskt generera terräng. Scenkomplexiteten och kraven för visuell kvalitet i dagens spel ökar ständigt. Därmed kommer också kravet för prestandaeffektiva renderingsmetoder. Deferred rendering är en renderingsmetod som kan hantera scener med stora mängder ljuskällor och hög scenkomplexitet samtidigt. För att undersöka integreringen mellan procedurellt skapad terräng och en deferred rendering pipeline, skapades en applikation i DirectX 11 för att undersöka implementeringen och potentiella optimeringar av denna integration. / Detta projekt handlar om slumpmässig procedurell skapning av digital terräng för bruk inom datorspel, och hur man i denna kontext kan ta nytta av en grafikmotor som använder renderingstekniken deferred rendering. / Carl Engström can be reached at: Phone: 076-102 86 00 Mail: Lemmibl@gmail.com Felix Nawrin Oxing can be reached at: Mail: felix@nawrin-oxing.se