Implenting WaitForVerticalBlank

[Roo Payne]

I'm trying to write a short program to test reaction times using LabVIEW. It needs to time the reactions of a person to a visual stimulus on the monitor, so I need some way of looking at the monitor refresh to avoid a ~20ms error. I note that previously people have used Active-X controls to access DirectDraw for the GetVerticalBlankStatus, GetScanLine and WaitForVerticalBlank:

http://forums.ni.com/ni/board/message?board.id=170&message.id=177811

My problem is I know nothing about Active-X controls or DirectDraw. I've placed an automation refnum on the from panel, selected DIRECTLib.I_dxj_DirectDraw, and wired this to an Invoke node, but I can't seem to get it to do anything! Any advice? (I'm using LV6.1)

Roo

[AdamB]

Hey Roo

You might need it to look like this?

You will need to actually poll the activeX node as often as you can to catch the change in status.

(I would actually use the "getScanLine" and some 'Jiggery Pockery' to work out when the new frame is updated)

Thanx

AdamB

[Roo Payne]

Hi Adam

I had forgotten to put an "automation open" in. Agree that using getVerticalBlankStatus and getScanLine works well. I don't think that waitForVerticalBlank is as easy to implement.

Thanks again

Roo

[@lex@ndre]

Has anyone had any experience with DirectX10 / Windows Vista?  I have no experience with Active X in older versions either, but am trying to reproduce the work you all have shown and am having trouble.

I'm not seeing Type libraries with names similar to Direct1.0

I do see:
Microsoft DirectX Transforms Core Type Library Version 1.1  -- some of these look promising
Microsoft DirectX Transforms Image Transforms Type Library Version 1.1  -- which looks like a bunch of image filters, probably not useful

Any help or pointers towards good references is apreciated.
--Alex.

[Wiebe@CARYA]

You could use .NET constuctor (Microsoft.DirectX.DirectDraw, Device,
Device() ).

Regards,

Wiebe.

[usrfrnly]

Well, maybe this WAS solved, but it appears i cannot access the Microsoft.DirectX.DirectDraw assembly because it is too old. Anyone know an alternative or what the updated .dll is called?