Skyboxes are not very good for space simulators because there is usually not enough geometry to obscure them so it's easy to see the imperfections. You'll notice texture aliasing right away, but if you use very large textures (1024x1024) you may get away with it.

I think Descent Freespace or some of these other space games use a sphere box. It probably helps with aliasing because the distances are more or less constant, while in the skybox they are not.

I'm using a skybox for my space sim and it's doesn't look very good. The textures are only 512 x 512 though.

I disagree sky boxes can work just fine for space games. For example i just use a sky box here:

The only reasion i ever use domes is for when i plan to animate the sky.

A correctly made skybox accounts for the distance variation towards the corners.

I use a skybox and to me it looks super fine, check the screens here... if the textures are generated properly with distortions, it works.


my proj

Quote:Original post by Erondial
Would I just create a sky box, centered around the camera in order to set up the background? Is that how it's done, or are there different methods?

Different methods to achieve the same thing :
- if you've got a cubemap (most hardwares support cubemap textures now) you can render a screen aligned quadrangle at max distance and you just specify the direction vector at corners.
- render a cube centered around the camera as you said. Of course if you do the calculation in your head you'll see that the only thing that matters is the orientation of your camera. So take your worldview matrix, strip the translation part of the matrix, strip the scaling part (it's easier to do if you just construct the matrix from your camera orientation information) and you'll end up with a matrix that can rotate a cube centered around zero. Then apply projection matrix on that, to project your cube on the screen. The real dimensions of your cube don't matter (because you're centered around zero and your projection center is also at zero, you're "scaling independant".. with the following caveat).

The second one can generate artefacts if you're not very careful (cube end up being clipped by far plane, or cube obstructs views of visible objects). You just need to make sure you write at a constant Z (the far Z).

Note that to save fillrate on some hardware, you can render your box last, after all opaque objects, your depth buffer will take care of occlusion. Then draw semi transparent objects on top as usual.

If you just need static nebulas and stars, skyboxes are fine. Make sure you generate the textures correctly of course (each face of the cube is a projected view of the environment).

LeGreg