I made a pyplug node with shadertoy for Blender Distort/Undistort. Everything works fine except this node doesn't update viewport correctly. If I zoom in viwport 50% or less, it will show correct result, if I then zoom out to a degree, more than 50%, it will just show very weird distortion. Is that a bug in shadertoy node? or I did something wrong?
Zoom out viewport to see 100% ( very weird result)
Zoom in viewport 50%
Render result is correct.
I also have it on Github in case anyone wants to take a look.