Y-Billboard Sprite3D does not cast shadows

[IanWark]

Godot version:
3.06.stable.official.8314054. I had also tried it on 3.1 with the same results.

OS/device including version:
Windows 10 Home
NVIDIA GeForce GTX 1080 with Driver Version 25.21.14.1967

Issue description:
3D sprites cast shadows when Depth Draw Mode is set to "Opaque Pre-Pass", but when Billboard Mode is set to "Y-Billboard" the sprite no longer casts shadows. Using the normal "Enabled" Billboard Mode works mostly as I expected "Y-Billboard" to also work (shadow is upside down but I think changing properties can fix that).

In this example screenshot, the closer sprite is set to "Enabled", and the farther sprite is set to "Y-Billboard". Other properties are the same.

Steps to reproduce:
Easiest is to open up the Minimal reproduction project and look at it.
Otherwise get yourself a light, a plane, and a sprite. Set the sprite material Depth Draw Mode to "Opaque Pre-Pass" and set Billboard Mode to "Y-Billboard".

Minimal reproduction project:
Y-Billboard Shadows.zip

[kaadmy]

So, this is a really strange issue.

If I create a MeshInstance with a similar material (transparent, opaque pre-pass, billboard enabled), the shadow works the same as the Sprite3D

But if I change the billboard mode for the Y-billboard sprite to a regular billboard, the shadow still doesn't work

And when I change the depth mode on the same sprite the new MeshInstance loses its shadow

I'm confused.

[Calinou]

If you can build Godot from source, please build the 3.2 branch and test this again now that #39867 has been merged. (That pull request also makes Sprite3D much faster to render.)

You can also use this Windows 64-bit editor binary for testing.

[golddotasksquestions]

I can replicate this issue in Godot 3.2.3 stable and 3.2.4 beta1 using Win64 and dedicated Nvidea graphics.

[ghost]

Is there any news on this issue? I still can replicate this in v3.3-stable.

[Calinou]

Is there any news on this issue? I still can replicate this in v3.3-stable.

As far as I know, nobody found a solution to this problem yet.

As a workaround, you can use a second Sprite3D or MeshInstance whose shadow rendering mode is set to Shadows Only in its GeometryInstance section and make this node a child of your original Sprite3D. This one should have a separate opaque material, and can use the standard (non-Y) billboard mode if needed.

[ghost]

I'll use the workaround for now. Thanks for the info