RE: [Algorithms] terrain texturing

[Charles B. <cb...@cb...>]

First of all, to the original poster (Timo), if your target
is high-end (GeForce2, XBox) you could use the "splatting"
technique ("compositing influence regions in the frame buffer")
which I describe at www.cbloom.com/3d/
It's similar to John's (and others') techniques in many ways,
though as John knows, the greatness is in the details.  Splatting
lets you composite many close detail maps of any configuration;
the cost is higher memory usage and many passes (no problem for
XBox; GF2 can get overloaded).

Now, John, there are a couple of points I'm not clear on :

At 02:59 PM 1/14/2001 -0800, John Ratcliff wrote:
>Now, when you get up close and personal I have a dynamically generated
>tesselated mesh that is created in real-time from the base mesh.  I use the
>same precomputed tables used for terrain collision detection so that I can
>generate this mesh in real-time with no performance penalty.

How does this mesh relate to the collision detection tables?

>This
>tesselated mesh is rendered alpha-blended on top of the main terrain. It
>shares the same lightmap data in the second texture channel, but texture
>stage one contains extremely high resolution close up textures.

I thought the lighting was baked into the original texture?  Do you also
keep around another copy of it in lightmap form, or does the original
texture also use lightmapping (eg. color * light) so that you can do
over-brightinening by adding dynamic lights to the lightmap ?

>You can only alpha blend from one texture type to another. 

So, granted you can set it up so that the places where multiple textures
meet are rare, but how do you handle those places when they happen?  You've
got to at least handle a three-texture meeting (since any N-tex joint can be
turned into a 3-tex joint) or it seems like there would be visible seams?
Maybe you can also say a little more about how this alpha channel is used
to blend the detail textures.

-------------------------------------------------------
Charles Bloom    cb...@cb...    http://www.cbloom.com