Hybrid Rendering in 3D Map-Based Grand Strategy Games

Abstract: Ray tracing comes together with a tremendous computational cost [1]. Therefore, Keller et al., expressed that possible cost reduction appears when a hybrid rendering pipeline is implemented by combining rasterization and ray tracing, which have already been introduced to the film and game industries. Such a rendering method within Grand Strategy Games (GSG) has been an unexplored task. The standard rendering method of GSG has been rasterization. Implementing hybrid rendering for GSG would allow this niche to follow the continuously developing rendering techniques. Therefore, this thesis examined the advantages and disadvantages of hybrid rendering compared to a path traced pipeline. The study measured different camera angles applied to three GSG-inspired scenes by rendering time and quality according to pixelby-pixel comparison focusing on effects like shadows and reflections. Closeup images have been taken on the rendered scenes to evaluate interesting pieces in the scenes. Steady time performance for all angles was the significant advantage of the hybrid pipeline. The angles at lower grades resulted in an increased difference in shadows and reflections for two out of three scenes. Additionally, the entire pixel-by-pixel comparison did not generate more than ten percent difference for any scene and not more than twelve percent difference on closeup images. Still, differences were noticeable to the eye since the path tracer was superior for developing sharp shadows. The hybrid pipeline generated a massive reflection compared to the path tracer. Since the path tracer was defined as the ground truth, this quantity of reflections was not considered positive. The thesis concludes that a simple hybrid rendering pipeline could be an exciting future for GSG, especially for angles above 67.25◦ . Additionally, improving the sharpness of the shadows for the hybrid rendering pipeline could increase the interest in hybrid rendering for GSG even at angles below 67.25◦ . Some interesting future work is rendering advanced 3D map-based GSG scenes, including more shadows and reflections. Another suggestion is a qualitative analysis of users playing a game with the two rendering pipelines before attending a user study about their possible improved graphical experience and how the game experience has been affected.