I have a setup with a dual head video card (Intel GMA 950)
I need to synchronize both screens to render a different image at the same
time at exactly 60Hz without video tearing.

I am creating a device like this:
for (unsigned int i=0; i<2; ++i)
present_parameters[i].PresentationInterval=D3DPRESENT_INTERVAL_ONE;

CreateDevice(adapter_id, D3DDEVTYPE_HAL, window_id,
D3DCREATE_ADAPTERGROUP_DEVICE | D3DCREATE_MULTITHREADED |
D3DCREATE_NOWINDOWCHANGE |
D3DCREATE_SOFTWARE_VERTEXPROCESSING, present_parameters, &device );

Then I have a simple loop to check that the displays are not tearing:

The only way I can ever totally avoid tearing is by using exclusive mode. I
haven't tried exclusive mode with several graphics adapters though.

Arto

"Arto" discussions.microsoft.com> wrote in message
news:F645C1BA-2B85-42B0-A530-38B3E1035DAC@microsoft.com...

It works. You need to create a window on each display, then create a device
for each of those windows. You'll be able to specify exclusive mode (which
you need set to be able to sync IIRC) for each of those devices. They may
still not sync perfectly with each other, but they will sync to the refresh
rate of the individual displays.

NB: The last version I did that with was DX8.1, so it's _possible_ it may
not work any more with 9 or 10.

- SamB

I have developed a renderer that synchronizes the display refresh rate to
the fps of the incoming video (e.g. TV), provided that they are close enough
to start with. A kind of "soft genlock". This solution might be possible to
adapt to two displays to compensate for any small differences in refresh
rate. Source code and more blah blah can be found here
http://www.ostrogothia.com/?page_id=405.

Arto

"Arto" wrote: