Use screen-aligned quads for origin lines to avoid issues on NVidia

[clayjohn]

While we are at it, use alpha-antialised lines to make them look nice

Fixes: #37016

I can't reproduce the issue on my device as it is a driver bug. But this PR should avoid it completely as it doesn't use rasterized lines.

Importantly, this PR does make the lines slightly thicker in order to antialiase them. That is a tradeoff that we have to pay.

CC @aaronfranke please try it out and let me know if you are happy with the solution

For posterity, the technique is based on the one described here: https://wwwtyro.net/2019/11/18/instanced-lines.html

Master: no antialiasing

This PR: no antialiasing

Master: MSAA 8X

This PR: MSAA 8X (note how this looks the same as no antialiasing)

[Riteo]

Why are the lines always antialiased?

[clayjohn]

Why are the lines always antialiased?

The linked issue comes from the lines aliasing. The solution is to antialias the lines. But since we don't want to force the viewport to always use an antialiasing solution, we apply one directly to the lines

[PZerua]

Just curious, the ~0.5ms increase in GPU time comes from this new method?

[aaronfranke]

@PZerua It's probably just random jitter, so I would not worry about it. It's a line, it should be nearly instant to render.

[clayjohn]

Just curious, the ~0.5ms increase in GPU time comes from this new method?

No. It's just random. You can see that the performance actually increases when using MSAA compared to MSAA on master.

[Calinou]

Tested locally on a RTX 4090, it works as expected (including when FXAA, TAA or FSR 2.2 is used). Using camera presets or orthogonal camera keeps the expected appearance.

That said, resolution scales lower than 1.0 will appear to make the lines thicker (this is also an issue with hardware-based lines, such as grid lines).

Regarding performance, it's pretty much identical (tested with identical ~4K viewport resolution, Prefer Maximum Performance power profile in nvidia-settings and Update Continuously enabled in editor settings):

Before	After (this PR)

[akien-mga]

Looks good to me.

[akien-mga]

Thanks!

[YuriSizov]

Cherry-picked for 4.2.2.

[atirut-w]

Importantly, this PR does make the lines slightly thicker in order to antialiase them. That is a tradeoff that we have to pay.

In my opinion, it looks very much better than before this PR. Can it be extended to other things?