#Screen grabber windows how to
#Screen grabber windows software
#Screen grabber windows code
#Screen grabber windows windows

#Screen grabber windows code

Once you have the pixels in hDest/hbDesktop, you still need to save it to a file, but if you're doing screen capture then I would think you would want to buffer a certain number of them in memory and save to the video file in chunks, so I will not point to code for saving a static image to disk. To change it to use a specific application, you need to change the first line to GetDC(game) where game is the handle of the game's window, and then set the right height and width of the game's window too. If there is no support for this they fall back to CreateCompatibleDC.

#Screen grabber windows software

I'm not saying this is the fastest, but the BitBlt operation is generally very fast if you're copying between compatible device contexts.įor reference, Open Broadcaster Software implements something like this as part of their 'dc_capture' method, although rather than creating the destination context hDest using CreateCompatibleDC they use an IDXGISurface1, which works with DirectX 10+. delete the bitmap you were using to capture frames. after the recording is done, release the desktop context you got. copy from the desktop device context to the bitmap device contextīitBlt(hDest, 0,0, width, height, hdc, 0, 0, SRCCOPY) use the previously created device context with the bitmap HBITMAP hbDesktop = CreateCompatibleBitmap( hdc, width, height) Int width = GetSystemMetrics(SM_CXVIRTUALSCREEN) Int height = GetSystemMetrics(SM_CYVIRTUALSCREEN) get the height and width of the screen HDC hDest = CreateCompatibleDC(hdc) // create a device context to use yourself This is still a decent way to go even with the performance advisory on that site, you can get to 30fps easily I would think.įrom this comment (I have no experience doing this, I'm just referencing someone who does): HDC hdc = GetDC(NULL) // get the desktop device context Hr = Device->GetRenderTargetData(pRenderTarget, pDestTarget) ĮDIT: I can see that this is listed under your first edit link as 'the GDI way'. copy the render target to the destination surface.

Hr = Device->CreateOffscreenPlainSurface(DisplayMde.Width, hr = pDirect3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,&d3ddisplaymode) HRESULT hr = Device->GetRenderTarget(0, &pRenderTarget) I can't recall where I found this, but it has been modified, thanks to whoever! void dump_buffer() This is what I use to collect single frames, but if you modify this and keep the two targets open all the time then you could 'stream' it to disk using a static counter for the file name.

From what I understand, this is faster than reading from the front buffer, because you are reading from system RAM, rather than video RAM. It hooks the underlying graphics API to read from the back buffer. Could someone give me an in-depth explanation on how it works, and why it is faster? I may also need guidance on implementing something like that, but I'm sure there is existing documentation anyway.Īlso, I now know how FRAPS records the screen. Could anyone fill in the missing blanks for me?Įdit: I read that screencasting programs such as Camtasia use their own capture driver. It mentions in the Conclusion that disabling hardware acceleration could drastically improve the performance of the capture application.

#Screen grabber windows windows

It has introduced me to the Windows Media API way of doing it and the DirectX way of doing it. Knowledge isn't bad, after all.Įdit: I came across this article: Various methods for capturing the screen.

The screencasting program will be for recording game footage, although, if this does narrow down the options, I'm still open for any other suggestions that fall out of this scope. The only method I'm aware of is to use GDI, but I'm curious whether there are other ways to go about this, and, if there are, which incurs the least overhead? Speed is a priority.

#Screen grabber windows how to

I want to write a screencasting program for the Windows platform, but am unsure of how to capture the screen.