help with 2 things

Hi guys, I need some help with 2 things:

-Terrain texture LOD (which is much more important than geometry LOD I think). What are the common ways of implementing this?

-Detail texturing: I have read there is an extention for doing that but only on some SGI boxes, so whats all about it? How do I implement it with 1.2 opengl?

Thanks in advance,

1/ the normal method is just plain mipmapping, also check ext_texture_lod_bias
2/ detail texturing is just a higher res texture combined with the previous texture.
eg you have a low res texture of a wall with bricks on it when the cameras close up you show that + also a texture if scratchs bumps ( the detail texture).

And 3 :

I think that geometrical LOD ismuch more important that what you think. (of course it depends of the kind of realistic - model you are using… )

Yeah…geometrical is more important than texture LOD (if you’re at least mipmapping the texture)

Oh well I just read the posts and realized I was using a wrong word. what I mean is not texture LOD, but texture paging for large-scale environments, where all textures do not fit into video memory and accessing textures from system memory is very slow (consumer level systems). Any ideas about that?

And to detail texturing: its clear to me what it is and how it works, but do I really have to check each n every vertex for distance (ok, with some visibility stuff like octree/bsp/portals) and then deside if I should apply a detail texture or not. Sometimes this check can be really expensive.


I think all you can do is tell ogl what textures have higher priority, (true/false style), and then just let it do its thing on the rest. I do believe there is no way to manage them your self.

Is glPrioritizeTexture implemented at all in the actual drivers?

Oh, if you have too big textures then you might at least try to draw the geometry sorted after texture flipped every frame. If two times of the hw memory is enough to hold all textures you can save half of the textures transfers.

Well theoretically.