SSAO doesn't work with material system

[slipher]

r_materialSystem 0, r_ssao 0

r_materialSystem 0, r_ssao 1

r_materialSystem 1, r_ssao 1

The last screenshot (material system + SSAO) is more similar to the first screenshot (SSAO off) than the second (SSAO on). Look at this line for example:

[slipher]

As discussed in #1600, instead of just having ~no effect, SSAO with material system can also cause bad artifacts in certain configurations. With dummygame and AMD hardware I get this:

[VReaperV]

Mesa or proprietary drivers btw?

[VReaperV]

It seems the original issue might also be hw-specific, since with r_ssao -1 I get this on Nv: r_materialSystem off: r_materialSystem on:

[slipher]

With Mesa.

With r_ssao -1, the SSAO lines blink on and off with varying frequency. I.e. sometimes it draws the lines, sometimes it is all white.

[illwieckz]

As discussed in #1600, instead of just having ~no effect, SSAO with material system can also cause bad artifacts in certain configurations. With dummygame and AMD hardware I get this:

I experienced this as well in the past, this screenshot is perfect to describe what I have seen.