Catch22 with viewport scaling and post-process shaders

[nickluvsretro]

Godot Version

4.3.2

Question

I have an isometric tile game, where I use a base viewport of 1920x1080 but then set the scaling in Project Settings to x4 to get the pixel size I want. This ensures that not only the tilemap and contents are the right size, but also that anything I add to the UI Canvas is also scaled up from pixel size nicely.

However, this means that any post-processing I do in a ColorRect operates on this 4x scale, so i can’t do things like scanlines, etc. that would require adding detail on a sub-chonky-pixel level.

The alternative is to use a 1:1 scaling and then zoom the camera 4:1 but this has the following caveats:

1. Camera movement is a bit too smooth and not as pixel-snappy as before.
2. The UI elements are all 1:1 and look tiny requiring all to be manually scaled up 4x and also positioned with pixel snapping.

I’d like to stick to the first method, but wonder if it’s possible to keep the 4:1 viewport scaling but have a post-process that works on the full 1920x1080 final render than the (480x270) area that viewport scaling seems to force it to?

Many thanks in advance for any help received.

[nickluvsretro]

Ah, figured it out and posting here in case it’s searched for in future.

I need to create a subviewport with the right dimensions.

Then use the resultant Viewport texture in a TextureRect that is stretched to full with aspect enabled. This then goes into the post-processing ColorRect.

Noice.