missile, this game made me think of your CRT effects:
http://store.steampowered.com/app/270090/
Hah, sick! But despite of the barrel distortion and some wired scanlines,
there isn't much CRT/video effects in there. Anyhow, their rough look fits
the game quite nicely. Well, I think they never indented to come close to a
CRT in any way.
Many devs just add barrel distortion and some scanline filters to make the
game look CRTish, which is okay if it really fits the game, but doesn't in
many cases. Many gamers don't like the scanlines done this way. Scanlines
need to be carefully adjusted. The video beam's point-spread function and
the resulting line spacing/resolution, etc. all need to be carefully adjusted.
Doing this rightfully one also has to take the observer's distance to the
screen into account. It's all interrelated. So adding them by just lowering
the luminance on every other scanline won't match many of the important
properties a TV was constructed from.
The only advices I can give for adding non-annoying scanlines to a game the
easy way (box-filtering the point-spread function to pixel width) is to tone
down the lines just slidly up until the player can see a slide difference to
the lines above and below while looking for them. This works as an
approximation to the real effect. Increasing the scanline effect beyond
this threshold shows the inappropriateness of box-filtering the point-spread
function. People will recognize the higher luminosity frequency between the
scanlines quite good while getting annoyed by them. To alleviate this problem
one has to approximate the effect in some better ways by for example using a
Gauss filter. Doing this, however, will diminish resolution and the problem
becomes much more difficult all of a sudden.
However, adding very pronounced scanlines for artistic reasons is a different
story. In this case there won't be any rules so to speak.
The reason why a standard old TV wasn't annoying to look at stems from the
fact that many of the variables like resolution/lines, scan rates, point-
spread function, the TV's diagonal, the viewing distance etc. were all
interrelated and tuned to make a TV viable to watch for hours. All these
quantities are interrelated. And this makes it difficult to produce a proper
video effect. And we haven't spoken about the oddities a TV may produce by
itself, nor about signal distortion etc. One can write a thesis about it! xD