Why is ambient light flat?

[Rick]

If the only light in your scene is ambient lighting everything looks flat compared to other types of lighting. My question is why? And does it need to be that way? Can't ambient light run similar code as the other lighting to give the models some pop?

 

I ask because we have a game where you have a house and when you go into the house the roof goes away so you can see inside but we want both the lighting to be realistic and models inside the house to look good. To make the lighting realistic we block the directional light from entering the house (discard pixel shader) and have the ambient light be darker gray but the inside of the house is so flat and boring then.

 

To me it seems normal map data isn't considered with ambient lighting. Can it be? Otherwise I don't know why we'd ever want ambient lighting because it looks so bad.

[shadmar]

It has really no direction, so it will always look flat, no normals will be calculated,

AO + ambient looks slightly better.

[Rick]

Do we have AO?

 

I wonder if another light source that is like ambient light (hits everything) but with direction is valuable? I mean when you have indoor and outdoor settings it's hard to get the indoor setting that doesn't have a light source of it's own to look good. I guess this wouldn't work either huh. It's just hard to get darker indoor scenes without a direct light source to look decent.

 

[edit] Looks like if you place a bunch of point lights and play with color/lighting you can simulate darkness while getting model normals to make the model pop. Just requires some 3 point lights per house object which I hope doesn't kill performance later when there are a ton of houses.

[shadmar]

That's a nice idea, make short viewrange and disable shadows at light level.

[Josh]

I remember the first time I fired up a map I made in the Quake Engine, I wondered this.

 

Lighting requires...a light. It's a complex calculation that needs exact input values. No lights = can't come up with a correct equation.

 

SSAO does a good job of giving definition to the scene. You can also do other things like modify the ambient light shader to modulate the brightness by the normal. Just a small tweak will make geometry more visible, like it does in the "Solid" view mode in the editor. I did not include anything like this by default because I did not want to add anything that was confounding or imprecise. If was publishing a finished game, I would probably do a combination of SSAO and a small shader tweak to give more definition.