I'm planning on implementing rotating things in game made of voxels, so this is why I'm experimenting with image rotation via shearing.

I wrote a simple program to test image rotation via shearing.  (See previous devlog post).  Some insights gained:

• For 90 degree rotation, a temporary image must be used that is twice the width and height of the original image to not get cut (magenta) by applied shearing
• If the image is rotated for a given amount of degrees, anything beyond 90 degrees causes image to become "chewed up"
• Multiple of 90 degree rotation will be faster by a transposing axes transform
  • Combining multiple of 90 degree rotation via transposing axes transform and then shearing by remainder (less than 90 degrees) will result in correct rotations up to 360 degree

Here's an animated gif showing my experiment (0 to 180 degrees of shear only rotations):