Getting Started with Spheremaps?

Blitz3D Forums/Blitz3D Programming/Getting Started with Spheremaps?

BlackD(Posted 2004) [#1]
Hi

I'm creating a space shooter and the inevitable time has come to introduce the backgrounds. I'm proficient at creating "cube-map" skymaps, however in a space game these look crap, therefore sphere maps are needed, like this:



Unfortunately, I'm unable to find a good way to convert cube maps into spheremaps. Most resources on the net confuse spheremaps with domemaps (or skydomes), such as this:



Programs like WorldBuilder create dome-maps which I don't really know how to use. I'd rather just paint a texture straight onto a sphere, in the manner the first example is useable.

Could someone either point me to a resource showing me how to create spheremaps (or convert cube maps into spheremaps) or else give me pointers on using dome-maps (for which there are plenty of cubemap converters) in Blitz3D.

Thanks,
BlackD


BlackD(Posted 2004) [#2]
There used to be a plugin tool for Unwrap 3D to do this but I can't find it anymore, and don't have Unwrap anyway. :p But if the plugin is available in a standalone form? (Cubemap>Spheremap conversion)


Bolo_Loco(Posted 2004) [#3]
SphereMap Generator ( Standalone )

http://www.unwrap3d.com/downloads.html


BlackD(Posted 2004) [#4]
CHEERS! :D

actually, using both of those progs together makes up everything i need.. How could I have missed that link? >_<


Warren(Posted 2004) [#5]
I'm proficient at creating "cube-map" skymaps, however in a space game these look crap, therefore sphere maps are needed, like this:

If they look crap, you must be doing them wrong. Using a cube or a sphere as your sky, as long as it's mapped properly, should show no discernable difference in the game itself.


jhocking(Posted 2004) [#6]
Why are you using a cubemap for your sky? A cubemap is for shiny objects to reflect the sky, not for the sky itself. The sky should be a normal texture map, mapped onto geometry with correctly set texture coordinates. I prefer skyboxes to skydomes in all cases because the texture mapping is simpler.

EDIT: Rereading your original post, I see that you are all mixed up with the vocabulary. You use the word "spheremap" to refer to a normal texture map designed to use on an object with spherical texture coordinates, and you use the word "skydome" to refer to a spheremap (you also use the word "domemap.") A spheremap, or spherical environment map, is a texutre image designed for use with spherical environment mapping, a technique to dynamically alter an object's UV coordinates. A skydome is a geometrical object (a hemisphere specifically) that covers the scene and has a texture image of sky applied to it. Domemap is presumably a word you made up.

Oh, and you use the word "cubemap" to refer to a skybox, when in fact cubemap is, like spheremap, a kind of environment map. Like a skydome, skybox refers to a geometrical object (a box this time) that covers the scene and has normal texture image of sky applied.

That all cleared up, skyboxes work perfectly fine for space. As mentioned above, I prefer skyboxes to skydomes (or skyspheres) in all situations because of the simpler texture coordinates.