opengl: Using CanvasItemMaterial with BLEND_MODE_SUB makes the editor disappear.

[lyuma]

Godot version

4.0rc1 gl_compatibility only.

System information

Windows 10, Nvidia 527.56 RTX3090, gl_compatibility
OpenGL API 3.3.0 NVIDIA 527.56 - Compatibility

Issue description

Assigning a CanvasItemMatrial with blend_mode = BLEND_MODE_SUB in opengl causes the entire editor to turn black and break, even if later unassigned.

In case it matters, I'm using Single Window Mode in the editor.

Steps to reproduce

1. Open the attached Project. Make sure it is using Compatibility on the top right.
2. On the root "Level" node, click the Use Standard checkbox which runs the tool script (it actually sets a CanvasItemMaterial, not standard. the checkbox was badly named). The editor turns black.
3. Without moving the mouse, click again to toggle this material off and return to a ShaderMaterial. The editor is still black / broken.
4. Press Ctrl-S to save the scene so you aren't bombarded with an invisible save dialog.
5. Close the editor.

If you edit the script and try other blend_mode values, this issue does not happen.

Minimal reproduction project

black_screen_test.zip

[lyuma]

Apparently the test project I was basing this on was using gl_compatibility. This bug does not occur in vulkan Forward+ or Mobile

[clayjohn]

Related to #72488 Although that issue is with 3D