Min-max mipmaps for efficient 2D occlusion culling

Abstract

3D culling techniques are well established to improve rendering performance, but cannot be applied to 2D games in which the scene is composed of partially transparent textures in a known layer arrangement. Commonly, 2D rendering is achieved in a simple back-to-front blending scheme. This paper discusses options to realize 2D occlusion culling techniques using standard OpenGL functionalities, and introduces a novel 2D culling technique based on min-max mipmaps. We evaluate the performance of the different techniques for different scenarios.