Irradiance map generator issue #2
Description
Hi, I am not if the irradiance map generation in the ibl-converter is correct.
For the irradiance texture, horizonal pixels of the top and bottom of the image should be pretty much the same but it is not the case from the image generated from the tool.
If you look at the polar sides of the generated irradiance map at: https://oframe.github.io/ibl-converter/, it doesn't seem to be right. I think it the problem is at here: https://github.com/oframe/ibl-converter/blob/master/src/shaders/DiffuseShader.js#L98-L100
If the normal.y is getting close to -1 or 1, it will be wrong when you do the cross product with the up.