reading from depth texture disables depth test.

[darthLeviN]

Godot version

4 beta 6

System information

Kubuntu

Issue description

When reading from the depth texture in the shader, everything becomes messed up if it overlaps itself.
I think when this happens no specific draw order is imposed.

Steps to reproduce

1- Make a model that overlaps itself
2- Make a shader material that reads from DEPTH_TEXTURE.

Minimal reproduction project

gd4test.zip

[Calinou]

Duplicate of #63675 (same cause – see below).

Reading from the depth texture forces the material to be transparent, which causes transparency sorting issues. These are an inherent limitation of the rendering engine, and cannot always be resolved.