Tonal Mapping

Started by Sethren, December 28, 2006, 07:26:06 pm

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Sethren

Had anyone found the tonal mapping feature in TG2 yet or is it not implemented? What i would like to do is variate the colors slightly of each instanced population of flora, even stones.

Sethren

Does anyone know what i am even speaking of?  Unless i am just using the wrong description.

choronr

I know what you are speaking of and wish I could offer a suggestion. I haven't noticed a description of this process in the 'User Interface Overview'. It certainly would be a good thing if we could add some varigation to stones, rocks and grasses for a more natural look. Now, when populating the terrain with these  items, they all appear monotone. Perhaps the future and final version will have this ability.

        Bob

Sethren

Hmm. Hey JavaJones. Do you know of the tonal mapping shader i am speaking of. I could have sworn there was something about this that was discussed sometime back.    :)

RealUser

I have found soem information about ToneMapping ...
http://en.wikipedia.org/wiki/Tone_mapping
This is a bout HDR imaging. If i understand you right, you are talking about color variations? This should be possible by overlaying an image map to the whole of the objects (a forest for example), no?
Correct me if i have a wrong idea about what you talking about. ;-)
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Sethren

Sorry... i am talking about color variations per each instanced object, imported or not. I might have thought there was a node somewhere in terragen 2 that did this.

Oshyan

Yes, "Tonal Mapping" is not the correct term. I suppose simply "instance variation" would describe what you're after - I'm not sure there's a more technical or specific term than that.

I have done things similar to what you describe, but I'm not sure precisely how to do what you want as far as color adjustment. What I did was use Surface Layers to *add* color to existing textures within TG2. I put a Surface Layer shader in-between the Default Shader and the Multi-shader inside an object node. Then I connected the Surface Layer to the Compute Terrain node so it can get a normal to operate on (I did this by editing the .tgd file in a text editor, it seemed the easiest way). Then I was able to control the application of my surface layer by height, slope, etc. However this just adds color, it doesn't really adjust the color that's there. There is a "Colour Adjust" shader, but it doesn't seem to have the right inputs to do the same sort of thing. Hopefully just knowing my approach with the Surface Layers can get you a start for experimentation though.

Certainly the population variation options will be improved in the future.

- Oshyan

Sethren

Tonal Variation! That is what i wanted to say.     ::)
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I found the conversation we had a while back that about this subject.

crisscaprioty quote:

Tonal variation in TG2. So this means if i wanted an huge forest of the same species of trees but with slight color variations from the shader one can do this.

So with geometry variation one can slightly alter the shape of the instances?

Can't TG2 Alpha do multiple instancing now? What is the difference?

JavaJones quote:

You can do multiple instances with different instance generators. It's just easier to be able to use one instance generator with multiple variations. It's more work to have to setup each variation type, basically.

With geometry variations you can primarily just alter stuff like height, scale, width, rotation, etc. Which in some cases is appropriate (particularly height/scale), but is of course not as good as having actually different 3D models. Still it's surprising how different a single model can look from multiple angles, especially with tonal variation.

- Oshyan

I hope this makes things more clear to what i had in mind assuming this is possible.     :)

Oshyan

Well, as I said, the best I can hope to offer right now is pointing you in the right direction, as I've done above. I'll try to experiment with this stuff myself soon, but there's lots to do. :D I did post an example of some of the results I'm getting in my current experiments over here: http://forums.planetside.co.uk/index.php?topic=226.msg1451#msg1451

- Oshyan

Sethren

Alright, i will look as far into this as i can. Try to de-frassel my brain here.    ;D

Oshyan

Word 'round the campfire is you should be able to get this to work by using a "Tex coords from XYZ" node (under "Other Shader") in there. Note that if this is connected in the wrong place it'll make you lose your UV coordinates so the base textures won't apply correctly. The "Text coords" node needs to be added somewhere *after* the default shader.

So in theory you could use a merge shader to multiply the original tree textures by another color function (like a Power Fractal or Image Map) but the second color function would need a Tex Coords From XYZ above above it.

See what you guys can come up with. I'll try playing with this soon myself. Thanks go to Matt for the hints. :D

- Oshyan

Sethren

January 04, 2007, 02:51:44 am #11 Last Edit: January 04, 2007, 02:57:07 am by Sethren
I will try to get around to this as soon as i can. Been very busy and frustrated with my whole HDRI issues at the moment. Thanks to Matt for the hints though.