Pushed version with minimal changes to the code. I did delete a comment referring to the removed code.
Actually the original code had vec2(...) / 2.0 which apparently is compiling everywhere so I'm not convinced that the vec2(...) + 0.5 needs a cast. Seems likely addition and division are…
The comments are from a second patch, I'll remove that. And remove unnecessary changes.
I'm curious what platforms the automatic cast to vec does not compile on? Though I believe it is harmless…
I'm reopening because I was able to fix it. See pull request
I do not believe the limitation to bilinear sampling is causing this problem, as it would only lead to identical artifacts at each end of an integer-sized rescale, and this effect is off-center.
…
Further investigation reveals that this is a general compositor problem with the Scale node. It looks like scales that would produce a non-integer result size do not make an accurate scale, and…
My mistake was I did a save-as for the image in order to compare it with the composite in an external program, I did not know this unpacked it.
This one proved to work (I deleted the on-disk texture) and I switched the main pain back to the 3D view.
It looks like I did not save the image with the white edges, here is an updated .blend file. I also made it scale the background in all cases by making the render output
It appears that…
Figure out a way to toggle between the composite view and the background image, and the offset is obvious.
No I am not talking about the problem when portions of the display window are clipped.
The problem is there appears to be an offset of about 1 pixel (or maybe 1/2 pixel) between the viewport…
I agree, I was confused because for some reason my viewport was very close to 1:1 scale with the render, producing slight offsets. If I had zoomed it in/out I probably would have figured out what…
For the life of me I cannot figure out how to make it alpha composite the render atop the background. It acts like the alpha is 1.0 everywhere in the render. For this example I set the Fac of the…