Fix socket indices of Principled BSDF node

[MoritzBrueckner]

Apparently, Blender changed the Principled BSDF sockets a second time between 3.0-3.3 without a note in the release notes, at least I can't find it anywhere.

This PR fixes parsing normals and emission values. Emission is still pretty broken since we have no space left in the gbuffers to save any emission color (#1774), and I don't think that we can fix it without a 3rd render target. However, this would mean that either the 3rd render target would be bound all the time during mesh rendering, or we'd need to sort the meshes each frame to prevent to many context switches and maybe also bandwidth issues (I'm not sure what affects the bandwidth in what way, more specifically where it matters). @ luboslenco do you have an opinion on this? I think the current emission support is a problem, but I can also understand if you say that improving it would waste too much performance.

Here's a comparison between Blender and Armory, the cubes on the left use the Principled BSDF node, and the cubes on the right use the emission node. If you want I can add this file to the armory_calibration repo, but as you can see it doesn't completely work yet:

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Off-topic: what exactly is rp_render_to_texture supposed to do/solve? There's a bug with transparency if this flag is disabled, I found two possible fixes and my decision about what fix to choose depends on what this flag does.

[e2002e]

Hi, i just read that. I'm not familiar with GPU programming, yet having one more texture in the shader should cost nothing. I'm quite sure about that.

[luboslenco]

and I don't think that we can fix it without a 3rd render target

If there is no way around it we can go with the 3rd render target. Ideally it would toggle itself on/off if emission use is detected in a project? For a start let's just attach it during mesh rendering.

If you want I can add this file to the armory_calibration repo

Yeah, that might come in handy.

what exactly is rp_render_to_texture supposed to do/solve?

When rp_render_to_texture is disabled it should render directly to the screen framebuffer, instead of our own allocated texture / render target.