terrain/water/depth fog - seeking advice, suggestions

1. This really isn't my area so I'll leave this one open. Just out of curiosity, why are you going to a skyplane instead of a skydome? In my experience a dome gives much more pleasing results near the horizon.

2. I'm not sure how to go about this because I'm not sure how you're storing your terrain, whether the water level changes, etc.; but for the foam itself I'd suggest a simple white, foamy-looking texture that gets billboarded onto specially created polys near the edge of the water. You can make several different textures and animate them as well, making the foam look like it is... "foaming."

3. From what I can see it looks nice. The color is a little bit too bright to be believable, but that really isn't a major problem. Dropping off to black IMO doesn't look as nice. Maybe darken the fog color by a few percent and it should be perfect.

4. At night, I'd suggest not doing the translucency in the water; make it fully reflective. A well-placed light (e.g. the moon) can provide very nice looking specular reflections on the water, which is what a lot of people think of when they think about water at night. Beyond that, just play with your lighting and shading, and try to keep the details from becoming too cluttered. A lot of "starry" backgrounds end up having too many bright stars and are very distracting to the eye. A very few bright stars, many dim ones, and a few hazy blurs should work nicely. Comets, meteors, etc. are all nice but they only "work" in certain atmospheres; this is really more of an artistic thing so it is rather subjective.

Well it wasnt going to be a completely flat plane, it was going to curve off towards the horizon, just wondering if this is what most other people did as well.

thanks for the advice.

Looks nice so far.

I would make water and terrain fade in the background (skydome/cube) and not in fog. This way you get no "pop in the view" errors at any view distance. It also dosn't need fog to be matched with sky color.

For clouds you could keep the skydome. Use vertex colors for gradient and map texture to it for clouds. Just project virtual skyplane to dome and you have virtualy infinite horizon. But it might be a bit difficult to get animation/shading working with this. (sample image)

That looks pretty good, but I think the water is too bright. I'd darken it like ApochPiQ said. I'm curious, what does it look like when you use black fog? Can you post a comparision image?

There you go, looks kinda odd though with the bright skybox. I changed the water color as well.

Also, how do you make the terrain fade off into the skybox? Im not sure it will look correct however, as though even far off in the distance you can still usually make out the outline of the terrain on it. But anyway, you cant simply set the fog color to do that, right? I assume you'd have to write a shader for it.

Quote:

Original post by Vulcan Also, how do you make the terrain fade off into the skybox? Im not sure it will look correct however, as though even far off in the distance you can still usually make out the outline of the terrain on it. But anyway, you cant simply set the fog color to do that, right? I assume you'd have to write a shader for it.

You have different options. An easy one works like this:

* Render the sky
* render the terrain only in the depth buffer, ie. disable colour updates
* enable blending, based on alpha
* render the terrain again, this time with full colours, using a depth compare function of EQUAL
* use the fogfactor to modulate the amount of blending with the background (the sky). Conceptually, you render your terrain translucent, with a transparency depending on the distance.

Another approach uses vertex shaders and an additional texture unit, but can do it in a single pass:

* prepare the pipeline for your terrain renderer
* bind a cubemap of your sky into a free texture unit (you can use a lower resolution)
* at each vertex, compute the vector pointing from the camera to the vertex position, normalize, and use as index into the cubemap (be careful that the coordinate frame used for the raycasting is consistent)
* also compute the fogfactor per vertex
* per pixel, blend your final terrain pixel colour with the cubemap based on the fogfactor

And many more alternative techniques (for example storing the fogfactor in the alpha component of the framebuffer, and blending over the sky as postprocess).

You should make the fog color be the same as the "primary color" of your skybox, or some color slightly darker than that. Usually, this is a cyan-blue, or blue-purple. At night, fog should fade to black, or very dark purple.

You don't need to put the sky plane into a cube map for the water; the water is flat (modulo bumps) so using a simple reflection of the flat sky texture will work fine.

Tricking out the shoreline (especially concave areas) with horizontal polygons, and scrolling textures on them, is a time-honored way of doing rolling waves. You can see it very clearly in games like Black & White, for example.

thanks for your help all!

working on the fog stuff, seems relatively straight forward.

-Eric