Both look identical to me. However, the shader is by default being compiled with a fine-grained mask that is made for low resolution screens. To get the mask that is intended for normal screens, you need to edit the file:
And edit this line:
// in front of it:
Then, you need to fix a code mistake. Find this line:
float whichmask = fract(floor(vTexCoord.x*params.OutputSize.x)*-0.3333));
And remove the last parenthesis so it looks like this:
float whichmask = fract(floor(vTexCoord.x*params.OutputSize.x)*-0.3333);
Now you should get a proper CRT mask.
Unfortunately you’ll need to do this again if you update the shaders in the online updater, unless you copy
shaders/zfast-crt.slang to somewhere else and use the copies.
Perhaps it’s a good idea to add a new preset to the official shader package that uses the coarse mask so that people won’t have to edit the file.