Ambient Lighting Solution?

[Ishtvan]

I just saw this on D3World in the new patch discussion: http://www.doom3world.org/phpbb2/viewtopic...7&start=20:

 

Likewise. I've added a "simple lighting" mode to the next EMZ release which uses two global lights in diagonally opposite corners of the world, which works reasonably well.

 

We've had problems with the ambient lights acting on surfaces as if they're lit from a particular direction. Does this solution of placing two ambient lights coming from opposite directions actually "fix" this issue?

[New Horizon]

I just saw this on D3World in the new patch discussion: http://www.doom3world.org/phpbb2/viewtopic...7&start=20:

We've had problems with the ambient lights acting on surfaces as if they're lit from a particular direction. Does this solution of placing two ambient lights coming from opposite directions actually "fix" this issue?

 

Would be more expensive. I think our best best would be to use the option bloodrayne requested awhile back. Basically, it involved using a shader blend pass to control the stages.

 

Quote from the thread.

 

When you say 'Ambient Lighting' are you referring to true ambient lighting, rather than the ambient light shader that already exists?

 

We made it like this: Each texture has an extra (additive) shaderpass (which is the diffusemap). This way we can avoid having to use extra lights (we're lighting up the ambient diffuse factor).

 

We've put these extra passes into each material that needs one. What we'ld like to do is make a console variable available (r_ambientlightfactor) where 0 = no extra ambient at all and 1 = fullbright. This way people can choose wether or not to use the ambientlighting system. Then we can put that value with a slider into the mainmenu gui no probs.

 

You can find the lowdown on this technique here: http://www.doom3world.org/phpbb2/viewtopic...t=ambient+light

[Ishtvan]

Is it still more expensive than an extra pass if it's not a shadowcasting light? I would've thought it would be about the same, but don't know much about rendering.

[SneaksieDave]

In addition to the console var, it'd be good to have some kind of value global to the map (in worldspawn maybe?) so that the author can set his/her desired level of ambient. Then, the player can decide "too bright" or "too dark" and adjust if needed.

[OrbWeaver]

I just saw this on D3World in the new patch discussion: http://www.doom3world.org/phpbb2/viewtopic...7&start=20:

We've had problems with the ambient lights acting on surfaces as if they're lit from a particular direction. Does this solution of placing two ambient lights coming from opposite directions actually "fix" this issue?

 

If they are "ambient" lights, it doesn't matter where you put them -- the light will always appear to come from the same direction. You might be able to do this with non-ambient, noshadow lights.

 

Is it still more expensive than an extra pass if it's not a shadowcasting light? I would've thought it would be about the same, but don't know much about rendering.

 

Assuming they both involve an extra rendering pass per affected surface (which may be true, I don't know exactly how the blend types are implemented), I would expect lighting to be slower because it involves the use of the pixel shader, which a simple GL blend does not.