Re: [Flightgear-devel] Flightgear-devel Digest, Vol 4, Issue 55

[Syd <syd...@te...>]

> > I thought of masking , but don't know enough yet to try that,and I
> > understand it's a 2 stage process. The only thing I think might work
> > would be RendertoTexture, but I'm not sure.Need to learn more.Think
> > it's doable , or has this all been tried before ?
> 
> I think the best option is a stencil-based clip. Assuming you have a  
> polygon that represents the clip outline, just draw it with color  
> writes disabled, stencil write enabled, then draw the 'clipped'  
> objects as normal, with the stencil test on. This can also be made
> to work for 'nested' clips, if you draw each successive clip area
> with the stencil test enabled as well.
> 
> Also, any hardware that can run FG reasonably has hardware stencil  
> support, so the performance impact should be negligible, if not zero.
> 
> James

Thanks James, I'll try that route then .I WAS wondering about stencil
buffers , you answered most of my questions!
Cheers,
Syd