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New feature to create smooth indirect lighting and more about refraction!

Posted by unrealer2 on Feb 20th, 2011


We added another feature to our lighting system, which we call "Indirect Lighting". Although it's called "Indirect Lighting" it is not real indirect lighting like in global illuminaton, but rather a simple fake of it to get smooth lighting effects. We can render it dynamically at nearly no cost, and used properly it can bring you some nicly lit images using only a few lights at once. This scene can be completley lit now by using only one single point light:

IndirectLighting News

To render our IndirectLighting we use a rather simple formula. We calculate the lighting as we would usually do, but without respecting the normal-vectors of the world. So we get a gradient from the middle of the light to it's bounds. Then we subtract the standard lighting from it and color both results in their own colors:

IndirectLighting News
IndirectLighting News

Though this is so simple, I don't think I have not seen this in a game. This is our last head, rendered with "IndirectLighting":

IndirectLighting News


We improved our refractions by removing those wrong pixels at the border of the refraction when another mesh is in the front of the refractive surface:


For more information visit: Wtechportal.com

Post comment Comments
Tombofsoldier Feb 20 2011 says:

Ehh... not a fan. It looks weird and grey and like bad light bleeding. I'm more of a fan of a spherical harmonic ambient term, essentially a single spherical harmonic irradiance probe, combined with SSAO. Produces a nice way for normal maps to have definition as well as subtle (or not so subtle, if that's your preference) ways to differentiate between normals pointing in different directions. And of course SSAO is just plain good at giving visual clues as to objects spacial relationships, as well as being at least somewhere in the vicinity of having a physical basis.

+4 votes     reply to comment
[WuTz]! Creator
[WuTz]! Feb 21 2011 replied:

I see now, we should have put a screenshot of it used in a real scene into the news. You simply cannot say "it's weird and grey". Maybe it looks a bit weired to you, but it is not grey! :P Why not? It can have it's completely own color. You can make the diffuse light black and the Indirectional light bloodred.

More shots are to come, giving better examples of how it can be used like what's possible with the other light types.
We didn't show a directional light, but you can use our technique to set the lighting of the backfaces.

+1 vote   reply to comment
DaveW Feb 21 2011 replied:

I'd agree with tombofsoldier, the effect as you've shown it could lead easily to washed out images. Used sparingly it might look ok, but assuming you're essentially ramping up the brightness/colour of shadows you'll also lose a lot of contrast and detail (the image of the head shows this).

+1 vote     reply to comment
unrealer2 Author
unrealer2 Feb 22 2011 replied:

The samples above are a little bit extreme, we know. This feature can help you to illuminate a room more or less realistic. If you take a look around you, most seems do be unlit because of a diffuse reflection of light. Our "IndirectLighting" is just a very simple fake, but most time it is enough to get a good result and it costs no performance at all. You should keep in mind, that it is optional and adjustable. SSAO and similar will be build in with the other post process effects.

+1 vote   reply to comment
scott_aw Feb 21 2011 says:

I think if you use it right it could look very nice. The harsh shadows are really only realistic in an atmosphere with only a few sources of light, where as an out door lighted areas would have soft shading.

The fact that you need less point lights to light up a room is a plus in its own though.

+1 vote     reply to comment
thedaemon Feb 21 2011 says:

This is called Ambient Light in most 3d software packages. Keep up the good work, looks nice.

+1 vote     reply to comment
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