On Mon, 4 Mar 2002, José Fonseca wrote:

> On 2002.03.04 19:13 Leif Delgass wrote:
> > On Mon, 4 Mar 2002, José Fonseca wrote:
> > 
> > > ....
> > >
> > > But why does the number of levels has to do with the maximum texture
> > size?
> > 
> > As I understand it, a mipmapped texture is composed of several levels,
> > which are copies of the texture at different resolutions (so you can
> > choose a level based on how far away from the camera the primitive
> > getting
> > the texture is), so the total texture size in terms of memory is the sum
> > of all the texture levels in the mipmap.
> > 
> 
> Yes, that's the idea I had. I found reference to it in the OpenGL spec, 
> pp. 120-121, and there it says that the maximum texture size must be at 
> least 2^(k-lod)+2*b_t, but it doesn't specify in any way that 
> MAX_TEXTURE_SIZE is derived from the max lod . This prevents Mesa to 
> describe the limitation of devices not capable of doing mipmaps yet 
> capable of handling textures bigger than 1x1...

I need to read up on this a bit more, but in essence, my idea is this:  
let Mesa deal with the textures as if we are going to do mipmapping (this
is probably necessary for software fallback for textures).  The docs say
that the hardware can handle 11 texture sizes from 1x1 to 1024x1024.  So
pick a max levels that will allow the largest image size of the mipmap to
be accomodated by the hardware.  But when actually choosing to upload
textures (assuming that mipmapping is truly broken), just pick the largest
image available (wich should be the lowest tObj->Image[] element
available, right?), and only upload that single image.
 
> > 
> > Sure, maybe I missed something before.  At any rate we can try to get
> > single textures working right before dealing with multitexturing.
> > 
> 
> Yes. Good point.
> 
> > 
> > --
> > Leif Delgass
> > http://www.retinalburn.net
> > 
> 
> José Fonseca
> 
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-- 
Leif Delgass 
http://www.retinalburn.net




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