Shaders: noise and wave distortion now work uniformly instead of diagonally
Previously Noise and Wave texture nodes would use noise functions within a [0,1]
range for distortion effects. We either add or subtract noise from coordinates,
never do both at same time. This led to the texture drastically shifting on the
diagonal axis of a plane / cube. This behavior makes the Distortion input hard
to control or animate. Capabilities of driving it with other texture are also
limited, diagonal shifting is very apparent.
This was fixed by offsetting the noise function to a signed range and making it
zero-centered. This way noise is uniformly added and subtracted from coordinates.
Texture pattern sticks to main coordinates which makes it way easier to control.
This change is not strictly backwards compatible, there is versioning to ensure
the scale of the distortion remains similar, but the particular pattern can be
a little different.
Differential Revision: https://developer.blender.org/D6177