Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion
Summary
Sean Barrett analyzes screenspace ambient occlusion (SSAO) in game rendering. He argues that corners often appear darker in SSAO renders due to a mix of approximation errors and lighting models, not because corners are truly dark. He supports his view with photographs, graphs, and an Appendix containing code that demonstrates how brightness is sampled and plotted; he concludes that corner-darkening is subtle and often perceptual, suggesting caution when using SSAO in production.