I haven't seen anyone over use the SMAA in SweetFX - mostly because it's very hard to over use SMAA.
I have seen plenty of my users who abuse the other effects though. Some people have the mistaken notion that more = better and crank up sharpening and vibrance to ridiculously high values...
I did some tests on my own and you can indeed skip the texture lookup whenever In.Fade.x goes below 1, without being able to tell the difference.
However seeing is this is already such a simple shader it's bottleneck is the export and not the texture lookup on most platforms, so you really...
Humus, is the texture lookup in the pixelshader really necessary?
Since the phonelines are only 1 pixel wide, it seems to me that you could simply use an already defined color .. perhaps the vertex color.
A quick idea : During development apply this to everything in your scene, and then only show (or highlight) the pixels that were affected, to detect good candidates to apply this technique to in the final product - rather than guessing what geometry it might be good for.
Looks like you forgot to close the dot() function.
I'm guessing it should be
float3 gComputeIndirectLight(float4 indirectDirection, float3 indirectColour, float4 scatterDirection, float3 scatterColour, float3 lightDirection, float3 lightColour)
{
float3 light =...
Have anyone considered using subpixel rendering?
It works for anti-aliasing fonts (ClearType) so I don't see with it wouldn't work for other types of graphics.