Yo people. Just wanted to share two of my renders I really liked. Unfortunately, due to the quality of the pics, I can only show one of them on here, though I will link both of them from my deviantArt account for all to check out.
First one, Sand Storm, a desert scene implementing the redirect shader, and other things such as a ground-level cumulus to simulate a sand storm. http://www.deviantart.com/deviation/46931556/ (http://www.deviantart.com/deviation/46931556/)
Second one, Final Sunset, uses a really high intensity light source along with a mix of procedural terrain and a planet surface shader. The city lights effect was done with a scattered, luminous surface shader using a cloud fractal shader instead of a power fractal. Stars were done thanks to a tip I picked up on the forums :D .http://www.deviantart.com/deviation/47434831/ (http://www.deviantart.com/deviation/47434831/)
Both great renders! Your idea for city lights is also interesting, though they look a bit too irregular to me. I wonder if a Perlin Ridges fractal with 2-3 octaves might be somewhat more convincing, as city lights in real life tend to follow roads and whatnot.
Quote from: swiftstream on January 27, 2007, 02:56:24 PM
Both great renders! Your idea for city lights is also interesting, though they look a bit too irregular to me. I wonder if a Perlin Ridges fractal with 2-3 octaves might be somewhat more convincing, as city lights in real life tend to follow roads and whatnot.
True... should try something along those lines, but a normal power fractal doesn't get the scattered effect well enough, so I gave it a go with a could fractal shader... might redo the render in low res until I get the city lights effect done better, though it was worth a shot...
That's a very good sandstorm effect...
Very nice sandstorm look. I like your displaced rocks and walls as well.
I've been thinking about how to do proper city lights for a planet. The best source of inspiration for this kind of work is to look at a photo of earth (or Celestia, for a 3d light source and rotateable earth with city lights). You can see that cities tend to be densest near coastlines and then cluster sporadically throughout inland areas. And yes, there are visible "road strings" but only really noticeable at low altitudes and along major thoroughfares.
How to simulate this with a shader model? Well, I think a good starting point is to use a density map based on coastlines, and Perlin ridges does seem like the best idea to get the road effects, although it might be worthwhile to consider a seperate shader for that. Also, when seen through the atmosphere, city lights tend to be whiter. Aerial photos show city lights as yellowish. The whitening from orbit is caused by the yellow being washed out by the atmosphere. It's a similar effect that causes red stars and mars to look pale when seen from earth-bound telescopes.
Or an image map.
http://visibleearth.nasa.gov/view_rec.php?id=1438 (http://visibleearth.nasa.gov/view_rec.php?id=1438)
You could extract the relevant section using a program like PTGui.
http://www.ptgui.com/ (http://www.ptgui.com/)
If you use an equirectangular projection to convert DEM data to a TER you could calculate the coordinates to just crop the full globe image.
Quote from: bigben on February 05, 2007, 05:55:44 PM
Or an image map.
http://visibleearth.nasa.gov/view_rec.php?id=1438 (http://visibleearth.nasa.gov/view_rec.php?id=1438)
You could extract the relevant section using a program like PTGui.
http://www.ptgui.com/ (http://www.ptgui.com/)
If you use an equirectangular projection to convert DEM data to a TER you could calculate the coordinates to just crop the full globe image.
Interesting way to do it, but I kinda tried to see if I could simulate the effect with a fractal based distribution system. Wasn't easy, but I could keep giving it a try until I come up with something good...