Corners Don't Look Like That: The Truth About Screenspace Ambient Occlusion
Corners Don't Look Like That: Regarding Screenspace Ambient Occlusion
I argue that game developers misuse Screenspace Ambient Occlusion, creating unrealistic dark corners and artifacts. By analyzing real-world photographs, I show that actual room lighting is far more complex than current approximations suggest. The common belief that corners are naturally dark leads to code producing visually incorrect results, ignoring factors like soft shadows and indirect light reflection.
"I believe this is because people think the corners of rooms actually are dark, and they've allowed this belief to let them write code that produces unrealistic results."
HN discussion
- Ambient occlusion is a natural phenomenon describing contact and core shadows under even lighting, serving as a cheap cheat to add visual definition to concave corners where full global illumination is too expensive.
- While the article critiques SSAO's realism, practitioners note that early implementations in games like Fallout 3 successfully added necessary depth to simplistic lighting models, even if the effect was not physically accurate.
- The pursuit of photorealism often conflates camera artifacts like lens flares with true realism, whereas some developers aim for a 'more realistic than reality' aesthetic that enhances readability and engagement.
- Stylized graphics can be equally immersive as realistic ones, suggesting that the industry's obsession with physical accuracy may be overrated compared to cohesive artistic direction.
- Modern alternatives to SSAO include local radiosity approximation via ray marching, though historically the technique relied on detecting sharp depth buffer transitions due to performance constraints.