Game Design 1.0: Making Alien Planet Textures

This week I spent about two days making a better planet for our game, and one that we can use in our trailer. I followed this tutorial http://www.blenderguru.com/videos/create-a-realistic-earth/, which is quite good. The only problem was that I didn't want to use NASA photos of Earth, because our game takes place
in a different part of space (maybe a whole other quadrant, I don't know). Our planet still has the same colours has Earth (this was the look decided-upon), but the continents, oceans, and (noobish)clouds are completely different. So I guess I'll talk about how I made the textures.

Start off with a photo of a rock. This one is nice and smooth but still has noticeable features that could be mountains and canyons. You can make it a seamless texture by opening Photoshop and going to Filter-->Other-->Offset, then offsetting the picture enough to see the seam. You can now fix this seam using the rubber stamp tool.

Next you need to add an ocean. This part is the most tedious. Believe it or not, I actually picked a very fine brush in Photoshop and actually drew in all of the coastlines on the planet. This was very time consuming but completely worth it. The oceans I made looked like this:

I also added rivers and lakes in a few places, and made the oceans slightly transparent so that it would not look completely flat. You can use the same offset technique to fix the edges of the oceans, then offset them back in place. I added snow at the top and bottom of the planet to hide the valence points in the geometry, and then lightly coloured on grassy areas as well as deserts using a mostly transparent brush. Dark, almost black, areas at the points where the ocean is deepest add a nice touch. So is adding lighter patches where the ocean is quite shallow. After all of that, I ended up with this:

The clouds are a bit tricky. I'm not even quite sure exactly what I did, but here is roughly how I made clouds.

1. I drew a bunch of random white splotches and lines on a black background(in Blender it is possible to make black areas see-through)
2. I applied a Gaussian blur to make everything look diffuse
3. Then I used the Liquify tool and swirled and smudged the clouds to look more like  the NASA cloud map of Earth
4. I applied a filter to make the cloud edges look rougher.
5. Rendering cloud noise as a mask to the layer also helped roughen up the clouds
6. I increased the brightness and contrast till there were only very bright or very dark areas

This method didn't create the best clouds, but I did not find a better way of making clouds. This is the cloud map

All you need to do to make a planet from those textures is follow the tutorial in the link at the top. And since you've made the planet texture yourself, you can make the grass and oceans any colours you like.