About the alpha blend and alpha test in 3D

Hello everybody,

I'm working on a demo base on WPF. In the 3D part, I found that avalon only
do the alpha blend but no alpha test when drawing partual transparent
objects, Just like tree billboards and so on. So the pixels of the totally
transparent parts will also be drawn into the depth buffer(and prevent the
things behind it to be drawn). In DirectX, I can turn on the alpha test
renderstate to avoid this. If avalon is based on DirectX, is there any way
to turn the alpha test function on? Or avalon do not support this?

By the way, it seems avalon do not support the DXTC compressed textures now.
There is a large scene in our demo, so the display memory on the card will
always be eatten up quikly. Does anybody know how to enable it to use
compressed texture formats?

Thank you very much

See my CollageView sample at http://www.therhogue.com/WinFX/

It shows a Z-Buffer sorting technique, as Avalon (WPF) does not have this
feature.


"Arthur_liu" wrote:

> Hello everybody,
>
> I'm working on a demo base on WPF. In the 3D part, I found that avalon only
> do the alpha blend but no alpha test when drawing partual transparent
> objects, Just like tree billboards and so on. So the pixels of the totally
> transparent parts will also be drawn into the depth buffer(and prevent the
> things behind it to be drawn). In DirectX, I can turn on the alpha test
> renderstate to avoid this. If avalon is based on DirectX, is there any way
> to turn the alpha test function on? Or avalon do not support this?
>
> By the way, it seems avalon do not support the DXTC compressed textures now.
> There is a large scene in our demo, so the display memory on the card will
> always be eatten up quikly. Does anybody know how to enable it to use
> compressed texture formats?
>
> Thank you very much

Thank you very much. we will try your methord but I am afraid we may
encounter the performence problem - there are too much buildings and trees in
our scene. It seems the alpha test is the best way to resolve this - I pray
in the coming releases of avalon this function will be opened.

"TheRHogue" wrote:

> See my CollageView sample at http://www.therhogue.com/WinFX/
>
> It shows a Z-Buffer sorting technique, as Avalon (WPF) does not have this
> feature.
>
>
> "Arthur_liu" wrote:
>
> > Hello everybody,
> >
> > I'm working on a demo base on WPF. In the 3D part, I found that avalon only
> > do the alpha blend but no alpha test when drawing partual transparent
> > objects, Just like tree billboards and so on. So the pixels of the totally
> > transparent parts will also be drawn into the depth buffer(and prevent the
> > things behind it to be drawn). In DirectX, I can turn on the alpha test
> > renderstate to avoid this. If avalon is based on DirectX, is there any way
> > to turn the alpha test function on? Or avalon do not support this?
> >
> > By the way, it seems avalon do not support the DXTC compressed textures now.
> > There is a large scene in our demo, so the display memory on the card will
> > always be eatten up quikly. Does anybody know how to enable it to use
> > compressed texture formats?
> >
> > Thank you very much