This is a very old bug that I thought 2.55 had fixed along with a bunch of other negative layer stuff, but I did a fresh test after writing a workaround for it in my Scrolling Backgrounds script and it does indeed seem to be consistent between all versions. When drawing to layer -2 or -3 with DrawLayer() and scrolling the screen, part of the layer gets cut off as the screen scrolls. I also observed a weird flash effect where it appears the layer drew twice in the same frame at the start of the scrolling transition.
Here's the script I wrote to test it. It's doing nothing aside from drawing the layer. The opacity setting has no effect on the bug. I have it transparent for the video because it shows the second bug, which I believe may be a timing issue with 2.55.
global script Main2{ void run(){ while(true){ Screen->DrawLayer(3, 1, 0x20, 0, 0, 0, 0, 64); Waitframe(); } } }
This was all tested on 2.55 Alpha 92, Build 57.
Edit: Did an extra test in 2.53 just for comparison. The first frame flash is not present, the drawing bug is the same scrolling left or right but doesn't appear to be present when scrolling up or down. So 2.55 made it worse. Joy.
Edited by Moosh, 29 April 2021 - 07:48 AM.