From: "Curtis L. Olson" <[EMAIL PROTECTED]>
> Norman Vine writes:
> > Curtis L. Olson writes:
> > > We might need to learn more about how the imposters are rendered.  I
> > > don't think this is an issue of drawing the imposter once it is
> > > generated, but in generating the imposter in the first place.
> >
> > The Impostors are generated with regular OpenGL calls just
> > like everything else and then read out of the back buffer into
> > a texture which then serves as an 'impostor' for the real OpenGL
> > object.  eg you are substituting a glQuad for the entire set of
> > calls that were made to draw the object initially.  hence the
> > name 'impostor'.
> >
> > You can see the impostors getting created after you find and follow
> > the directions in this line in SkyCloud.cpp
> > // Uncomment this swap buffers to visualize cloud illumination
computation.
> >
> > Whatching these things get created gives you a GOOD ideaof how much
> > work the 'impostor' is saving you
>
> Mark Harris mentioned that the back buffer requires a "destination
> alpha" for imposter rendering to work.  Perhaps that's why things
> aren't great with a 16bit color buffer, you probalby aren't even
> getting an alpha channel there?

Perhaps we can create another, 32bpp, context to render imposters instead
of using the main one ?

Cheers,

-Fred



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