Hi all,
I’m working on rendering nicely my map, and especially forests. Here’s what I could come up with:
Now my issue is the following, I want to be able to play on the forest ambiance. For me this forest ambiance is probably rendered by three things:
Clearly modifying the shadowmap of my map, so that below trees, the grass (and actually to be realistic, I should replace the grass by some normal forest mud) should be way darker (so I know how to do that, that’s not the issue)
Adding some kind of light halos like this : 
(not exactly sure how to do that)
Adding some kind of fog area, that would give the impression of density (you couldn’t see through the forest). Especially that’d be really important as some points of the forest will be more malefic than others, so I in those specific places I would make the fog more toward black. I have not much idea on this too … (I know there exist fogstates, but how to make it only valid for some specific volume (under the trees) of my map ???
Any suggestion ?
Thanks a lot!
Adrien
Instead of a FogState, maybe you could create a few big and slowly moving particles to simulate ground fog.
It may be working better to include the fog directly into the model (animation) of the forest(floor), to make it follow the terrain better and introduce reactions to wind ect.
Antoher way might be to use a large quad, and then per shader do everything needed moving, follwing other stuff, ect per shader however this seems pertty hardcore.
> Instead of a FogState, maybe you could create a few big and slowly moving particles to simulate ground fog.
not bad, particles could actually come out of trees, or maybe trees from the middle of the forest. Now I'm wondering about the exact type of particles I should use …
[btw: has anyone every worked on volumetric particles ? marching ray shader ? I'm going through a lot of literature on the topic. If I manage to digest, maybe I could try something along this …]
> It may be working better to include the fog directly into the model (animation) of the forest(floor), to make it follow the terrain better and introduce reactions to wind ect.
Antoher way might be to use a large quad, and then per shader do everything needed moving, follwing other stuff, ect per shader however this seems pertty hardcore.
what do you mean include it in the model ? you mean on the Map mesh I'm using ? I actually was wondering about a possible implementation of a 'fog map' maybe along these lines. I could recreate a part of the map, extrude it to get a volume up to the top of the trees, and then render the fog inside this … but that'd probably be a lot of dirty work …
Didn't understand the second solution, could you explicit ?
I’m also interested about what shader could it nice to be used to have the ambiance wanted on this thread
Well basically the fog shader is quad that are given the highmap of the terrain and modifies itself in vertex shader so that it is always x higher. How to make the ground fog moving then basically the same as with moving water just a different texture and no reflections 
Btw for the halos it might be possible to use the newly(since then) added light scattering effect
i tried light scattering effect , it’s a nice one and very low frame rate , but it does work only if you are watching to the sun direction right ? or maybe i missed something. Anyway i absolutely did not understand what you meant with that fog heightmap terrain story , sorry lol . Why do we need to create a moving terrain ?
Well you can use a vertex shader to modify geometry.
Now lay a grid over your forest ground.
Give the fog materail the heighmap of that ground
→ shader modifies the fog mesh in a way that it follows the ground (like always 10cm above it)
Now you can togheter with the height information & the pixelshader display fog that slowly moves downward/with the wind like here.
http://www.oceanfootage.com/video_clips/DR35_077
But as I mention doing so is kinda complex to get a good reasult.
danath said:
i tried light scattering effect , it's a nice one and very low frame rate , but it does work only if you are watching to the sun direction right ?
Yes
the easiest way to do that would be to use geometries (like cones), with a translucent map on it.
nehon said:
Yes
the easiest way to do that would be to use geometries (like cones), with a translucent map on it.
Is there any example for that ? i'm not familiar and could be very interesting for a lot of people i think