Fix shaders with Compositor (again)

[colingeniet]

The following is all using the compositor branch rebased on master, and a recent (april 2020) compositor build. The default compositor pipeline works fine.

With the als pipeline, I get this:

But it get interesting when tilting the camera up:

It seems the shaders are not completely broken (as in they are rendering something). Notice how in the last picture the hull is a bit transparent, and fades away when the clouds are behind. It looks like the aircraft is rendered in the background, so probably something broken with z-values?

[colingeniet]

Forgot to mention, of course I did not get any error message in the console, or I would have posted it.

[colingeniet]

After 5 minutes of research, it obviously is a z-buffer issue, since Compositor was changed to use logarithmic z-buffer in shaders.

[NikolaiVChr]

I will fix that when 2020.1.1 comes out.

[colingeniet]

Fixed the logarithmic depth in branch compositor2. Now the real problems become visible:

[colingeniet]

To fix:

• [ ] The 'black checkerboard' is caused by the external lights. It disappears when turning them off.
• [x] As far as I understand, using /sim/rendering/shaders/skydome to test if ALS is enabled is not correct with Compositor. In the effect files, it seems like the test can simply be removed from the <predicate>, the correct shaders will be used if they are marked with <scheme>als-lighting</scheme>. However there are also tests in the model .xml files which need to be replaced.
• [x] Fuselage shader depth buffer is broken with low-spec pipeline and model shaders off. edit: I don't think it's a depth buffer issue, because the 'looking from below' trick does not work. It might just not be rendering anything.
• [ ] Display shader depth buffer is broken with ALS pipeline and model shaders off.
• [x] The fuselage is way to white (with ALS pipeline and model shaders on)

To insist, tests are required with at least every combination of the following parameters:

• Compositor pipeline default/ALS
• Model shaders on/off

[NikolaiVChr]

What external lights? landing/taxi or the others?

/sim/rendering/shaders/skydome will probably be fixed by Icecode so it can be used again. Think its a bug that it cant be used now.

Fuselage shader needs reordering of techniques, since model-combined was reordered.

[colingeniet]

What external lights? landing/taxi or the others?

Only landing/taxi indeed

/sim/rendering/shaders/skydome will probably be fixed

Good to know. It should be tied to the pipeline used by the compositor?

Fuselage shader needs reordering of techniques, since model-combined was reordered.

Thanks, this fixes the fuselage being broken on low-spec with shaders off. I will check if other inherited effects need the same.

[colingeniet]

Gamma correction is done higher up in the file now. With this line it appears you do gamma correction twice.

That sure didn't help. I blame git rebase for the duplication, and myself for not checking the diff.

[colingeniet]

Closing as it is no longer relevant. Compositor is now merged on next, and has very good backward compatibility. Also it currently does not include clustered shading, which was the source of the checkerboard issue.

The only changes that will be needed is to add shadows to the fuselage shader.