Asynchronous Shading in Object Space Lighting Compared to Forward Rendering

Abstract: Context: Rendering 3D scenes in real-time applications is becoming more computationally heavy all the time. Applications are demanded to render high quality graphics without going below a satisfactory frame rate. A huge part of the computation of graphics goes toward complex lighting of 3D models that has to be recomputed every frame. Object Space Lighting (OSL) is a recent technique that is able to store lighting data in between frames. This thesis researches how storing all shading data can impact the performance of an application. Objective: An OSL lighting application will be tested against a standard Forward rendering application in terms of performance, and image quality and perceptual deviations. Experiments are conducted using a scene that can have either still or moving lights and produces the results for the research. Results: Analysing the images from the results indicate that OSL is capable of rendering almost identical images as Forward rendering. The images are not perceptually different either. In terms of performance the hardware used for the experiments determines which application performs better rendering a scene with non-moving. Our OSL application shows clear weaknesses when rendering a scene with moving lights however. Conclusion: Finally, saving all lighting data with OSL is an interesting technique that with further research in the field could prove to be useful in a real time application under certain conditions.