Re: How do I tile a sphere ?

Lynton Towler schrieb:
> Hello,
>    Thanks for reading.
> In the past I have received help from you guys on this NG and am hoping 
> once again you could be so kind.
> I've been working on a 3D Earth type program using OpenGL with GLUT.
> Currently I load a rather large single texture of the earth and cover 
> the sphere with it, this works OK but is a bit slow at loading.
> I think I need to convert to a tiles approach where I divide the sphere 
> into say 512x512 tiles then texture each tile individually to speed 
> things up a little and make future zooming in easier.
> I could then of course load/cache each tile on demand when its within
view.
> These ideas are nothing new I know but I could really do with a small 
> skeleton tutorial or whatever on how to do this so if you know of one 
> I'd really appreciate it.
> I have Googled around a bit and found stuff talking of "Quad Tiles" etc 
> but no decent example code.
> 
> Thanks in advance
> 
> Lynton, England UK
> 

some ideas:

to tile the sphere you can use gluSphere() (www.delphigl.com) or some 
more native approach subdivide icosahedron (20 triangles). gluSphere() 
does the texture-vecs for you.

to speed up texturing check resident textures (glAreTexturesResident(), 
glPrioritizeTextures()). you can load (all/part) of the textures in the 
fast graphics buffer.

use only a half-sphere and only rotate the texture(s), maybe via your 
own pixel-shader. but i think this is advanced stuff.

cheers, chris