I made a fast CRT shader that combines the mask and curvature effects from CRT-Lottes with simple scanlines. I don’t have a RPi handy to do any actual benchmarking, but I get about 450 fps on my Sandy Bridge HD3000 integrated graphics. That’s about 10% slower than default CRT-Pi, but commenting either the mask or curvature options makes it run a little faster than CRT-Pi at default settings. Importantly, it should look pretty decent at non-integer scales.
It also has an option (commented out by default) to turn the scanlines vertical for TATE orientation.
The shader is called ‘fakelottes’ and is only available in glsl format at the moment. Here’s a shot of it at 3x scale:
I’m curious to hear how it runs on an actual RPi, if anyone has a chance to test it out.