http://forums.cgsociety.org/archive/index.php/t-66758.html
I only use this term in the context of ambient occlusion. Ambient occlusion refers to the exposure of each point on a surface to its surrounding ambient environment -- that is all objects/lights which cast ambient light into the scene. Usually this is a sphere enclosing the scene which has some HDR texture map casting light mapped onto it. All geometry present in the scene (including the object being shaded itself) acts as a blocker to light arriving from there. Additionally a certain distance metric is used to weight this exposure as this affects the 'contrast' and 'brightness' of the ambient occlusion and therefore the look of the shading.
Here (http://www-viz.tamu.edu/students/bmoyer/617/ambocc/) is a good explanation including pictures.
The surface normal is used for several shading calculations. Changing the surface normal hence changes the result of this calculation. A 'bent normal' is a normal that points into the average direction of light arriving at the surface point. All rays fired to calculate ambient occlusion are averaged together to get this new vector which is the (usually) used to look up the environment light texture.
Look at the pictures on the page linked above. The rays which are longest will contribute more to the average direction.
Cheers,
엠비언트 오클루젼 패스에서 더 좋은 결과를 내준다라...
Ambient occlusion just determines some sort of occlusion. This naturally is a part of calculating GI (but only a part). Using bent normals obtained in this pass to index into an evironment map for lighting is an additional thing which has nothing to do with occlusion per se.
Notice the term "occlusion"? Occlusion calculates occlusion from light, not contribution of light.
일단 엠비언트 오클루젼 생성을 위해서 벤트 노말을 이용하면 정확한 노말 방향을 쉽게 얻을 수 있어서 계산이 더 좋아지고 한다는 것 같은데?
빛 받는 디렉션이 픽셀단위로 정확해 지니까?
그냥 노말을 하려면 변환시켜야 하니까 무거워서?
그래서 GI 라이팅에서도 이걸 쓰면 좋다는 얘기로 들림.
자세한건 나중에 해야겠다.
너무 궁금해서 조사해 봄.
http://pages.cs.wisc.edu/~ltokheim/ambenv/
차폐가 되어 있는 부분을 맵으로 만들어 줌. AO를 보다 정확히 계산할 수 있게 해주는 것인듯.
실시간 SSAO 같은건 벡터를 여러 개 쏴서 차폐를 계산하는데, 이건 차폐가 계산되어 있으니까 좀 더 가볍고 좋은 듯..?
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