Normal map with unrotated camera will make a quad black

[nunodonato]

Operating system or device - Godot version: Tested in Godot 2.1.2 and Godot 3. Both display the same issue

Issue description:
Setting a normal map on a quad, with the camera facing straight at it, will show only a black quad. In the editor everything looks fine, but the problem appears when running the game.

Rotating the camera even a tiny bit will solve the issue. Which suggests to me that when something is 0, something breaks :p

Link to minimal example project:

Reported in Q&A with sample project: https://godotengine.org/qa/13060/cannot-normal-mapping-fixedmaterial-screenshots-project

[reduz]

this may have been fixed as i solved a normal map bug recently importing collada.. does it still happen?
i can't get the demo project

[reduz]

Quad node is gone and i can't reproduce this in current master using quad mesh, so closing.