speed question

[Keith W. <kw...@cs...>]

I have a trimesh with a texture.  Actually, I have lots of these.  In 
the distance from the camera position I want to use lower res textures 
on the object, basically lower dimension textures.  For the moment, I am 
considering not scaling down the mesh geometry by removing less crucial 
vertices and triangles, just downsampling the texture.  I think there 
are three ways to do this.  One is to use a mipmap and let Quesa 
automatically generate the downsampled mipmaps.  One is to create my own 
downsampled images and not let Quesa generate mipmaps (I know how to do 
this) and transfer them to the trimesh whenever the distance passes a 
crossover distance designating a switch in resolutions.  I think this 
requires copying the array of the new dimension texture into the texture 
shader pixel array.  I don't think there is any way to simply point the 
texture shader at a different downsampled array.  I think I have to copy 
the whole thing over.  The last way is to create multiple trimeshes 
during initialization, each one containing identical geometry by varying 
dimensions of texture.  I then only submit the trimesh that is 
appropriate for the present distance at any given time and ignore the 
other trimeshes until I need them for their respective distances.

Question 1: how wasteful is it to have extra trimeshes of identical 
geometry floating around in memory.  Is that just stupid, to have 
trimeshes of identical geometry and just different textures?

Question 2: of these three methods, which is best, which is fastest?

Question 3: is there a fourth way to do this that I haven't thought of?

Thanks.

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Keith Wiley                                kw...@cs...
http://www.unm.edu/~keithw                 http://www.mp3.com/KeithWiley

"Yet mark his perfect self-contentment, and hence learn his lesson,
that to be self-contented is to be vile and ignorant, and that to
aspire is better than to be blindly and impotently happy."
                                           --  Edwin A. Abbott, Flatland
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