Pull request for rotation not working

[RudyChin]

It turns out that calling abs instead of std::abs refers to the abs in stdlib.h, which is a integer version. So that the if clause will never pass through resulting in no rotation.

Also, I found that in calculating the rotation matrix, the if clause might be short-circuited.

[YuvalNirkin]

You are absolutely right. I'll use std::abs in the other if statement as well.

Thank you!