Key and fill

[Hawkwind]

Is it possible to do this in DirectX9 ( Apparently OGL supports this ) on
Quaddro cards ?

[Nick]

Yes.

[Hawkwind]

How?

[Nick]

You could use alpha testing, but the modern approach is to use a shader.

[Reedbeta]

Nick, are you sure 'key and fill' doesn't refer to key and fill lights (http://en.wikipedia.org/wiki/Three-point_lighting)?

In any case, the answer is still yes, you just need to set up two light sources.

[Nick]

Nick, are you sure 'key and fill' doesn't refer to key and fill lights (http://en.wikipedia.org/wiki/Three-point_lighting)?
No. But Hawkwind didn't specify. He might just as well be talking about color keying and filling the background. :whistle:

[Hawkwind]

Nope... confusion.... this is a TV thing... where the hardware does key and
fill on dual inputs to a single output ( according to a chroma key ). I am told
that OGL drivers support this with Quadro FX cards. This isn't the same as
just writing a shader to replace a colour (or range of colours), since the two signals are real TV input frame data and so to use shaders would require fast frame transfer, probably via DMA, and similar output.
Hope this clears up the confusion ( but probably generates more... )

[Nick]

Nope... confusion.... this is a TV thing... where the hardware does key and fill on dual inputs to a single output ( according to a chroma key ). I am told that OGL drivers support this with Quadro FX cards.
Could you point us to the OpenGL extension of that?
This isn't the same as just writing a shader to replace a colour (or range of colours), since the two signals are real TV input frame data and so to use shaders would require fast frame transfer, probably via DMA, and similar output.
So you're afraid that the latency of streaming in a frame and processing it is an issue? :huh:

Exactly what are you goint to use this for?

[Hawkwind]

This is TV stuff, and I've only got a vague idea myself at the moment. Something they asked me to look at (among 700 other things...) until I get
a Quaddro 5600 I'm really fishing in the dark here. I've never done OpenGL but
have done lots of game stuff in DirectX 9.
I was hoping that someone might have some experience with this TV sort of stuff otherwise I'll just have to wait until I get the Quaddro and play around
with it.
Cheers

[Mihail121]

Since your problem is a very specific one, I doupt there will be much info floating around on the net. It might be, that the hardware actually supports merging signals but you will have to get the exact specifications of how it is beeing done. As far as I can tell, nearly every card with a TV-Out allows managing signals (even my Radeon 9250) but tweaking of the drivers might be needed and some extra configuration. Sending request to the driver team might give you a start.

[Hawkwind]

Thanks