Tweaks to Frob highlight

[Baal]

@Arcturus: Thats the same problem. Neither normals nor specular are used by the highlight.

 

@Ihstvan: The shader could read the pixel values already rendered and only apply if they are under a certain threshold (as a first idea).

But I think the object has to be rendered twice for that as a surface with a post processing pass is not lit by light sources. How did rebb do his fresnel highlight?

[rebb]

@Baal ( re: your PM question ) :

 

The fresnel effect is drawn on top of the previous stages in the material, which includes the lit object.

 

And you can pass "_currentRender" whenever you want, the Doom3 Engine will then sort a stage that relies on it ( afaik ) to be drawn after everything else is done drawing.

 

It's true that postProcessing shaders have no access to lighting information in the scene.

[Baal]

Ok, thank you. Then it's not as restrictive as I thought.

 

So, what does everybody think about a new frob highlight? I think it would be very useful.

In case it's not clear what I propose: I want the highlight to actually light a surface through a shader that uses normals and specular. The difficult part would be to only let it effect dark surfaces and just highlight already lit ones.

[Springheel]

I have no problems with the concept, if I understand you correctly. Right now the froblight only affects the diffusemap, and you want to make it affect the normalmap and specular as well? I'd certainly be interested in seeing what that looks like.

[New Horizon]

I have no problems with the concept, if I understand you correctly. Right now the froblight only affects the diffusemap, and you want to make it affect the normalmap and specular as well? I'd certainly be interested in seeing what that looks like.

 

As would I.

[Baal]

Ok, I will experiment with this a little more. And I already did a test to illustrate the difference and posted a screenshot some posts ago (in case you didn't see it).

[Springheel]

I'd need to see the before frob/after frob comparison to get a good sense of what it is doing.

[Baal]

The screenshot above shows the current highlight (right) and my highlight test (left) of an item that is almost black unfrobbed.

But I have to do some work on that and test all the possible lighting situations before I can show something real.

[Flanders]

Any news on this? Some of the ideas looked promising.

[Baal]

I didn't get to this for a while now and I don't know how to do the specular lighting of the highlighted object yet. I'm not sure if it's possible through custom shaders but maybe the doom renderer can be used.

Is it possible to create a light that affects only the frobbed object? If somebody who knows the SDK could point me in the right direction that would be helpful.

[greebo]

You could play around with the spectrum stuff. From what I know, It's possible to have lights emitting a certain spectrum, and only shaders with that spectrum will respond to it.

[Baal]

Thank you, I have to look into that.

 

I don't have that much time to search through the SDK so could somebody give me a hint where to look for things concerning the interface to the renderer and maybe gamecode using it?

[rebb]

I've fiddled around a bit with the "shade the frobbed object better" idea and created something thats based on a .vfp file ( no, not the interaction ). Hope Baal doesn't mind

 

It basically shades the object ( taking normal-map, specular, diffuse into account ) based on the position of the player and adds the result onto the object to get the frob-effect.

 

At some point i tried combining this with the "have loot shaded a bit differently" idea by just coloring the specular highlights with a "loot color", like some yellow tint. But that probably doesn't work too well for loot that has no specular or is very gold-like itself.

 

This could potentially be combined with the fresnel-based loot-effect, but i didn't get around to trying that yet.

 

Here's a comparison between the current default frob-highlight ( left ), and the potentially new way ( right ).

 

 

Edit :

 

Unfrobbed Vase

 

[Springheel]

It looks a little better, but it's hard to tell without seeing the non-frobbed version.

 

What do you mean by "based on the position of the player"?

[rebb]

@Springheel :

 

The player's "eye-position", the object is sort of "lit" from it.

[Springheel]

Huh, interesting. Well, anything that increases the detail of a frobbed object is worth a look IMO.

[Baal]

Cool, that's how I imagined it. At least the idea was mine.

 

@rebb: I'm curious. Can you do that effect without SDK modifications? If I'm not mistaken you need to access some render state data in the shader and I didn't know how to do that.

[rebb]

@Baal :

 

Yes it's just .vfp and material-file modifications. All vfp files get some basic information passed in, like eye-position and vertex-info etc.

 

For example the vertex-program part of this is just copied from bumpyEnvironment.vfp that comes with Doom3, and the fragment-program part is customized.

 

Did you also use a custom .vfp file for the image here ? http://forums.thedarkmod.com/index.php?showt...st&p=175427

[Baal]

Yes, that was a custom .vfp shader. I just set a vertex parameter to a constant light vector in the material definition.

 

For the specular lighting you need the eye and light vectors and the tangent space transformation matrix (if I got that right). Is this accessible through the environment variables from a custom shader?

[rebb]

Yes you need both eye and light position for specular if the light-position is not the same as the eye-position.

 

An earlier version of this used to have the light-position being somewhere else, but that looked a bit odd, so i ended up just having the light be in the eye position.

 

That frees up some calculations and still looks good for what it's supposed to do.

 

The tangent-space matrix should be available to every .vfp, yes.

[Dram]

@Rebb: That frob effect is amazing! It should really reveal the details on loot etc, which is handy, rather then a bland additive pass.

[New Horizon]

Cool.

[greebo]

I like the new effect much better too.

[OrbWeaver]

Is it possible to animate the frob effect, for example by slightly moving the light vector around a bit? If the highlight pulsed or shimmered gently this might serve to bring out the effect even in bright ambient light without having to do something more obnoxious.

[rebb]

@OrbWeaver :

 

Quite a few things could be tied to Doom3's Timer, like making the effect pulse subtly for example.

Moving the Light-Vector around would be possible but probably needs some tweaking so it doesn't look odd.