SkyBox, VAR, VBO

[alucard]

Hi.

I´m doing a SkyBox.
Ans it´s has 3 possibles for creating.
With only one texture in every thing, with 2 textures, or with 5 textures. (My Sky box don´t has the botton).

So I need 5 quads.

And i´m thinking in what i will use.
I have writed a model class that use vbo or var.

Im thinking in use only display list for skybox, because it has only 5 quads. And have to create 5 vbos perhaps not will be too fast!

Anyone know the fastest way to do this ???

Thanks a lot!

[jwatte]

Geometry transfer is unlikely to be a problem for a sky box. It will be fill rate limited. You could poke the vertices at the card using two cups and a string, and it still wouldn't matter.

This is how we do it:
Artists model sky box in 3dsmax.
Artists export sky box just like any other model.
Artists give name of skybox in per-environment settings.
Sky box is rendered instead of screen clear, always centered on camera.

This just goes through the general model path. If they model a sky box with 18 textures, we'd get 18 different vertex buffers. (They use sky domes a lot, too, for some reason) It just doesn't matter.

[alucard]

I´m usign one moel file that I have created, an made a 3ds export for this.

But I´ve write a Sky class with SkyBox and will write SkyDome soon. I use the class, because many times I will change the textures from the SkyBox. So I will need 3 models, with only diferentes textures.

I want to know whats is better:
1º - Make a list with de glBegin(GL_QUADS), os the 5 quads.
2º - Or make 5 vertex array(float[]) and use var or vbo, or var with display list.

I want to know if use var in this case will be really better ?

[jwatte]

I already said that vertex transfer is not the issue here. You won't see any difference. It's 24 vertices.

[alucard]

ok, thanks!!!

[targe]

i don't see the point in writing your skydome class. Your skydome will have more faces to render than a simple box without a 'floor'.

although the 5 quads will be turned into 10 triangles on the card, sending 5 quads x4 verts (20) is faster than sending 10 tris x 3 vers (30).