Precomportal System Design And Implementation Of Novel Occlusion Culling System

Occlusion culling can be used in rendering to remove a significant amount of hidden objects.In traditional Portal occlusion culling system,the view frstum will be clliped by Portal to get real time potential visible set.In this work a novel occlusion culling system based on traditional Portal system which is called Pre Com Portal has been developed.In comparision with the traditional Portal occlusion culling system,Pre Com Portal prefers simplifying Portal representaion and precomputing the Cell-Portal-Area visibility,which reduces the high computational cost of Portal clipping operation in runtime.Compared with existing solutions,Pre Com Portal achieves a significant acceleration of the occlusion culling process at the cost of a lower occlusion culling rate.The key work is described as follows:1.By means of Portal representaion simplification,visibility precomputation,and improvement of volumetric Portal auto generation,Portal system's praticibility has been im-proved.2.Compressed visibility set data format has been designed and same data has been merged,which reduces the generated file size greatly,making system more suitable for the low end.3.An integrated toolbox enabling Portal automatic generation and modification,visibility precomputing,and debugging has been developed on Unreal Engine 4.Testing results show that Pre Com Portal reduces 87.5% occlusion cost,achieves 50% lower occlusion rate,and gains 30% more FPS compared to the software occlusion culling system provided in Unreal Engine 4.