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supertuxkart / stk-code

The code base of supertuxkart
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Add darkness to the reflections #1634

Open MatthewsSam opened 10 years ago

MatthewsSam commented 10 years ago

Currently with gloss/spec map, the reflexion is the skybox. This create a sense of realism but in the reality the reflexion (there is no perfect reflexion) so it's always darker than the reality. Even a perfect mirror will be always a bit darker compared to the real image.

So there is different ways to do that, We can set another cube map for the reflexion but this take work.

I rather suggest of putting an artificial darkness to the sky when it's used for the reflexion. It will be easier IMHO.

vlj commented 10 years ago

It will actually be required to use a separate cubemap for reflexion since using the skybox is only an approximation of the real specular term. Currently I only compute the diffuse component at loading time since it's in O(n) (where n is number of texels) and use a cheap approximation for the specular term but computing the right specular term is in O(log2(n) * n^2) which may be costly if n is 1024 x 1024. I'd like to move all IBL related calculus to python script (since they are far easier to maintain) that would be run at export time so having a way to import a second cubemap for IBL would be nice.

To be precise IBL requires 9 scalars per color for diffuse component (ie 27 coefficients) and sevel mip levels of cubemap depending on how much error we accept on glossyness. I would rather go for 8 mipmap level. So this means 6 x 8 = 48 textures for IBL.

Adding Auria to assignee

hiker commented 10 years ago

Postponed after discussion with vlj.