Transparent + no culling + deep parallax depth crashes editor

[sunkper]

Godot version: Godot 3.2 beta 4

OS/device including version: Windows 10

Issue description: Transparent + no culling + deep parallax depth combination in SpatialMaterial crashes editor. I think it displays correctly in editor's main viewport and runtime, but if you try to see mesh preview (not material preview) in inspector, editor crashes without any error message.

Steps to reproduce:

• Add SpatialMaterial to a mesh
• Set transparent true, select cull mode disable
• Enable depth, and enable Deep Parallax and add depth texture
• Try to see mesh preview in the inspector panel

Minimal reproduction project: SpatialCrash.zip

[akien-mga]

Tested on Linux and it's not crashing for me, but it does freeze for ~10 sec when I click on the preview icon, before properly showing the (transparent) mesh preview.

[KoBeWi]

Still valid in 3.2.4 beta3, tested on Windows 10 too. The material seems empty/invalid on master.

[Favkis]

Still crashes. Doesnt have to be transparent, alpha scissors crash it as well. Game runs fine, its only editor that crashes.