Add particle y-billboard option to standard shader

[Arnklit]

This adds a particle y-billboard option to Standard Material.

When used with Align Y on the particles it allows you to have particles that align themselves with velocity, but face the camera.

Note I'm not sure if this should be added since you can also achieve this with the "Particles -> Drawing -> Transform Align -> Z Billboard + Y to Velocity". But these options don't work with stuff like Particle Animation.

In general I'm not sure why there are billboarding settings both in the Particles and in the Material like this.

• Production edit: This closes Add a Preserve Orientation billboard property godot-proposals#5591.

[Calinou]

Tested locally, it works as expected. This is a great addition to have for VFX like water fountains, sparks and the like 🙂

I've looked at the code and it seems good to me.

Testing project: test_pr_88107.zip

simplescreenrecorder-2024-02-09_12.21.17.mp4

[QbieShay]

This needs to be discussed in a rendering meeting but we should try to understand where to put bollboarding options for particles. I'm not sure standard material makes sense.

[Calinou]

This needs to be discussed in a rendering meeting but we should try to understand where to put bollboarding options for particles. I'm not sure standard material makes sense.

The reason we had Particle Billboard in the material is that it allows for configuring flipbook animation, so if we remove these options, we have to make particle flipbook animation depend on another checkbox within the material.

[QbieShay]

More context: godotengine/godot-proposals#8367