2010-12-08, 02:02 AM
Actually on second thought, it's not much trouble to do a rolling fog, like across a landscape. However I think a point sampled fog would be easier to manage. I think ground fog tends to settle at a natural elevation and level out. But I'm not positive. I can see like outdoors fog rolling across the landscape. I'd have to look outside on a foggy day to get a really good idea. The only trouble with a rolling fog model is how to deal with the edges once you want to stop the fog. Basically if you stopped the fog suddenly it would still ramp up/down to the next pixel on the fog map, so you'd need to hide those areas. Whereas with a flat shaded fog so to speak it would just clip off. Though you'd also need to hide that. Ideally on a 200x200 map you could divide a tile between a wall, but I'm not positive that will always work.
There is also the question of whether you want a smooth fog like the fog we have, or like a dry ice fog where you can clearly see where the fog terminates. For a dry ice fog noise could be added to make it appear to boil a little.
My idea for this stuff is to do everything on a 200x200 map, and use the 56 pixel border (256x256 total) to store meta info about the texture, like what kind of fog you want, and where the elevation of the map is, units etc. I'd go ahead and implement this tomorrow-ish if I had a test file. Maybe when I start mucking around with the .mpx files I'll toss together a tool to generate an elevation map from the .mpx file. That would give you a kind of place to start anyway. An interactive painter (where the changes become immediately visible) would be nice but probably won't come for a while... not without a custom map editor anyway.
There is also the question of whether you want a smooth fog like the fog we have, or like a dry ice fog where you can clearly see where the fog terminates. For a dry ice fog noise could be added to make it appear to boil a little.
My idea for this stuff is to do everything on a 200x200 map, and use the 56 pixel border (256x256 total) to store meta info about the texture, like what kind of fog you want, and where the elevation of the map is, units etc. I'd go ahead and implement this tomorrow-ish if I had a test file. Maybe when I start mucking around with the .mpx files I'll toss together a tool to generate an elevation map from the .mpx file. That would give you a kind of place to start anyway. An interactive painter (where the changes become immediately visible) would be nice but probably won't come for a while... not without a custom map editor anyway.