Sprite3D not casting a shadow

[Tobi-La]

Godot version:

3.0 stable and 2.1.4 stable

OS/device including version:

Phone: Oukitel K6000 Pro
Android 6.0
GPU: ARM Mali-T720 (MP3)
Driver: Open GL ES 3.1 and Open CL 1.2

Issue description:
When using a Sprite3D with "alpha_cut" set to "Opaque Prepass" the drop shadow is missing on my Oukitel K6000 Pro. This happens in all versions of Godot I tested and seems to be device specific. I tested with two other phones (Samsung Galaxy S3 and Galaxy J5 Duos) and the issue only occurs on the K6000 Pro.

I am using Godot 2 for my project, so it would be glad it could be fixed there, too. But I tested and uploaded a test project for godot 3 to help fixing the issue on the current version.

Steps to reproduce:

1. Set up a basic project
2. Add a directional Light, a Sprite3D and some object to cast a shadow on.
3. Set the "alpha_cut" of the sprite to "Opaque Prepass"

Minimal reproduction project:

Godot2: Sprite3DShadowTest_Godot2.zip
Godot3: Sprite3DShadowTest_Godot3.zip

Screenshots Godot2 Project
Oukitel:

Other devices:

Screenshots Godot3 Project
Oukitel:

Other devices:

[ghost]

I don't know about rendering on mobile devices but I'd try removing Mali from here

[Tobi-La]

Thank you for the tip Noshyaar, unfortunately it didn't work. I also tried removing the other two vendors, just in case, but no difference.

[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]

Neither in Godot 3.2.3 stable nor 3.2.4 beta1 (Win64 with dedicated Nvidea graphics) Sprite3D shadows appear unless the alpha_cut flag is set to "Opaque Pre-Pass". However in which case transparency is not taken into account.