Background. The game-industry is rapidly demanding more and more comput-ing power in its strive for more realistic renditions of environments, simulations andgraphics. To accelerate the improvements made to the realism of real time graph-ics further, optimizations like Clustered and Cascaded Clustered Shading come intoplay. The purpose of these techniques is to reduce the time it takes to render aframe by dividing the view frustum into smaller segments called clusters that canthen be used for light calculations. Cascaded Clustered Shading is a slightly morecustomizable method which aims to improve on Clustered Shading by allowing morecontrol over how the view frustum is divided into clusters. Objectives. The goal of our thesis is to explore the effectiveness of Cascaded Clus-tered Shading compared to Clustered Shading in a scene with 64, 256, 1024 and 4096lights respectively. It is also to find the trend of what type of subdivision pattern thatperforms best in what situation. Thus proving or disproving the theory that moreuniform cluster sizes are beneficial in reducing the complexity of light calculations incomparison to the increasing cluster sizes present in Clustered Shading. Methods. To answer these questions we implemented the techniques in a test scenewhere we could easily compare the performance of the different subdivision patternsand techniques with 64, 256, 1024 and 4096 lights respectively. Three different pat-terns were tested, one with an increasing number of subdivisions per layer P1 (anincrease in the number of clusters per layer). One with a static number of subdi-visions per layer P2, representing the performance of Clustered Shading. One witha decreasing number of subdivisions per layer P3. Additional performance metricsto be recorded were added, measuring the time it took for the different parts of thetechnique so that not just the general performance could be compared. Thus themethod used was a quantitative research method of implementation and experimen-tation. Results. The results supports the theory that more uniform cluster sizes tend tobe beneficial when rendering a scene with many lights showing a clear trend to favora pattern creating more uniform clusters P1. However the results also show a con-tradicting overall performance increase (comparing FPS) using the reversed patternwith sharply increasing cluster sizes based on the distance from the camera P3. Theoverall performance of pattern P1 and P3 was better than P2. Conclusions. The conclusions drawn from the results are that Cascaded ClusteredShading perform better than Clustered Shading in most cases depending on the pat-tern, and that more uniform cluster sizes are beneficial when rendering many lightsin most cases.

Context. In this thesis, a GPU-based light culling technique performed with conservative rasterization is presented. Accurate lighting calculations are expensive in real-time applications and the number of lights used in a typical virtual scene increases as real-time applications become more advanced. Performing light culling prior to shading a scene has in recent years become a vital part of any high-end rendering pipeline. Existing light culling techniques suffer from a variety of problems which clustered shading tries to address. Objectives. The main goal of this thesis is to explore the use of the rasterizer to efficiently assign convex light shapes to clusters. Being able to accurately represent and assign light volumes to clusters is a key objective in this thesis. Methods. This method is designed for real-time applications that use large amounts of dynamic and arbitrarily shaped convex lights. By using using conservative rasterization to assign convex light volumes to a 3D cluster structure, a more suitable light volume approximation can be used. This thesis implements a novel light culling technique in DirectX 12 by taking advantage of the hardware conservative rasterization provided by the latest consumer grade Nvidia GPUs. Experiments are conducted to prove the efficiency of the implementation and comparisons with AMD´s Forward+ tiled light culling are provided to relate the implementation to existing techniques. Results. The results from analyzing the algorithm shows that most problems with existing light culling techniques are addressed and the light assignment is of high quality and allows for easy integration of new convex light types. Assigning the lights and shading the CryTek Sponza scene with 2000 point lights and 2000 spot lights takes 2.92ms on a GTX970. Conclusions. The conclusion shows that the main goal of the thesis has been reached to the extent that all existing problems with current light culling techniques have been solved, at the cost of using more memory. The technique is novel and a lot of future work is outlined and would benefit the validity of the implementation if further researched.

This thesis deals with the techniques of global illumination of the scene. The theoretical part discusses various techniques, focusing on processing in real-time using various optimization methods. It focuses to the technology of photon splatting using view sample cluster hierarchy. The main part is analysis, implenetation and measurement of mentioned method.