SSAO with Range and Falloff

After experiencing issues with SSAO noise on distant objects I wrote this little hack to make AO gradually fade out over distance. Example images are attached.

edit: I chose this board based on similar posts here. Please let me know if the post should have been made elsewhere.

INSTRUCTIONS

In Shaders\frag_ao.cginc, replace the line

Code (csharp):

1.  
2. occ /= sampleCount;
3. return 1-occ;
4.  

with

Code (csharp):

1.  
2. int depth_max        = 60;
3. int depth_falloff    = 16;
4. float depth_mod        = (clamp(depth,depth_falloff,depth_max) - depth_falloff) / (depth_max - depth_falloff);
5. occ /= sampleCount;
6. return 1.0-(occ-depth_mod);
7.  

AO will start fading out at distance depth_max until it disappears at distance depth_falloff. Tweak these values to your liking.

If anyone wishes to contribute performance optimizations, feel free - writing shaders is not my strength. Among other things, the entire AO code for a pixel could be skipped in depth > depth_max.



This is without the effect (the values are outside the visible depth range)

Gradual change ( depth_max and depth_falloff are distant)

Sudden change (depth_max and depth_falloff are near)