Uniform Ambient Lighting in GLSL viewport?

I’m trying to get uniform ambient lighting going in the viewport, because I want a preview of what a model would look like as a game asset. I’m after something that would effectively apply a constant low powered light to every vertex in the scene. My instinct for this was to change the ambient colour to a dull grey in the world settings, but all that does is wash everything out, as the picture linked demonstrates.

So is there any way to get what I’m after, or no?


EDIT: Giving the material a low “emit” value sort of works, though I have to do it for every material.