Thread: Quick Screenshot

I need a really fast way to take a screenshot and save it in a buffer for use in my program. Could use DirectX to get the main surface or something? If I have the a directdraw object and I lock the primary surface, does the buffer give the entire screen. Or is there a way to get the entire screen.

Press "print screen" (for the whole screen) or ALT-printScreen (for the current window).
Then just read the BMP out of the clipboard within your program.

> Or is there a way to get the entire screen.
http://msdn.microsoft.com/library/de...vcons_4esj.asp

I was using:

Code:

HDC dc = GetDC(GetDesktopWindow());
UINT screen_buffer;
//loop x and y
screen_buffer[y*scrn_width + x] = GetPixel(dc, x, y);

But that was way to slow because GDI functions are terrible. I don't know how to read from the clipboard, but if I can't get DirectDraw to give me the entire screen, I'll look it up.

Slow?
Are you planning to make a movie of your desktop or something?

Originally Posted by Salem

Slow?
Are you planning to make a movie of your desktop or something?

Ha ha. No, but good idea. I want to find bitmaps on the screen in real-time. Not to mention that my resolution is 1680 x 1050 so using GetPixel takes like 3 seconds on my machine.

You should (don't quote me, I'm a real noob at windows programming) be able to create a bitmap from the context, then access the pixels in that much more efficiently than calling getpixel on the context.

Replace my CSafeString instance with a standard C++ string method and this will do what you're after.

Code:

HRESULT CGraphicsManager::Screenshot()
{
	USES_CONVERSION;

	HRESULT hr;
	LPDIRECT3DSURFACE9 pTex;

	// create the image surface to store the front buffer image
	// note that call to GetFrontBuffer will always convert format to A8R8G8B8
	if (FAILED(hr = v_p3DDevice->CreateOffscreenPlainSurface(800, 600, D3DFMT_A8R8G8B8, D3DPOOL_SCRATCH, &pTex, NULL)))
		return hr;

	// read the front buffer into the image surface
	if (FAILED(hr = v_p3DDevice->GetFrontBufferData(0, pTex)))
	{
		pTex->Release();
		return hr;
	}

	// write the entire surface to the requested file
	CSafeString file("ScreenShot");
	file += ntoa(v_ShotCountS);
	file += ".BMP";
	hr = D3DXSaveSurfaceToFile( A2W( file() ) , D3DXIFF_BMP, pTex, NULL, NULL);

	// release the image surface
	pTex->Release();

	v_ShotCountS ++;
	return hr;
}

Originally Posted by Queatrix

>> I'm a real noob at windows programming
PrntScrn is that button on the top right of the keyboard I think.

Wow. You're definitely not allowed to talk again. First, you misread my original post. I want the screen in a buffer in my program. Pushing the PrntScrn button doesn't do that or I would have already done that. Second, Salem is one of the most respected programmers on here. And that idea that he gave in the post that you quoted is probably going to save me.

Correct. Sorry.
Correct again, Sorry again.