When I was using SetBlending, I was NOT clearing the screen each time. If I do SetBlending to 255, clear the screen, then SetBlending to the fade value, then plot my image, it works as expected.
I can't say I quite understand why that is, but it is working, so I'll understand later

I'd still like to know what was wrong with my pixel shader though... It seems pretty straight-forward. By the way, I did try resetting to the default shader and then clearing the screen, then doing my custom blitting, but that didn't make any difference either.
Thanks again Pam!
