The reason doors glow when a light is on one side is because of the way Lee made the lighting system for dynamic entities.
Here's how it works:
A dynamic entity is near a light (a door, for example), the system will "coat" the entity in the color of the light and make it brighter or darker depending on how far away the light is fromt he entity.
Since the entity is "coated" in the light, that means the ENTIRE entity will be bright and not just the side that the light is facing.
If there are two or more lights near the entity, then the system calculates the "average color" and "average distance to the entity" of the two lights, and then uses the averages for coating the entity in a bright color.
This is also used for providing information to shaders. The shaders are not given "light information", they are given "average light information". The perk to using shaders, though, is that the entity doesn't have to be COMPLETELY coated in light, and only the sides effected by the average light are effected.
So there you have it.. use a shader and your problem will be solved. Specifically, use a "Bump" or "Normal Mapping" shader which are shaders that run mainly off of lighting information.
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