. Wrote a little app to test the distribution of sample directions in the "magic square" of ThetaH/ThetaD
 => Distributions vary with incoming view theta, even after scaling V with a hard to compute table of ThetaL=PI/2
 => It means there's no practical way of storing these distributions in a static table
 => Hence there's no practical way to compute a unique table of importance sampling warping textures
 => ...Unless we create a 3D texture with sampling directions, but I'm still forbidding myself from doing this! ^^

. Bottom line => No easy way to spread sampling directions in ThetaH/ThetaD space with importance sampling... I'm pretty much fucked here. :(