I want to make volume clouds in OpenGL. I found an interesting article that describes a simple method for visualizing volumetric clouds. ( http://www.inframez.com/events_volclouds_slide18.htm ) However, I don’t know how to create their "fractal cube" (or a piece of perlin-noise).
My question is: how to create 6 tiled fractal cube textures?
Edit : my goal is to create a cloud cloud object, not a cloud skybox.
A good introduction to Perlin's noise, written by Ken Perlin himself, is here . He talks about generating a one-dimensional or two-dimensional noise function in detail, and then summarizes it to show how it will work in 3D, to create a solid cube of noise as you want.
When using a 2D-advertised cloud texture, you create an alpha-blended 2D texture where the transparency looks like a cloud. What they ask you to do is almost the same, only the texture flows around the cube without problems (for example, skybox). The perl noise filter looks like an algorithm that might look like a cloud.
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If you are really interested in good cloud rendering, then the Mark Harris algorithm is pretty good, albeit complicated: http://www.markmark.net/clouds/