Capturing screen using GDI is very slow (it barely captures 10 fps).

I have read that DirectX screen capture provides the best speed. I want to test some code to see if it is really fast before start to learn DirectX (I don't want to waste my time learning DirectX and then find out that it is not that fast ).

I have been searching for like 2 hours for a working example of a screen capture code. All I have found is incomplete code (the kind that assumes that you know DirectX and expects you to complete it yourself). For example: http://stackoverflow.com/questions/5069104/fastest-method-of-screen-capturing

Can anyone post a complete working example that will compile without a problem.

I am using Visual C++ 2012 Express on Windows 7 Ultimate x64 and I have installed DirectX 10.

I have read that DirectX screen capture provides the best speed.

from inside a d3d program, not from a separate stand alone screen capture app.

if you're writing a d3d app, you do it like this from inside your code:

void screendump()
{
char s[100],s2[100];
int i;
IDirect3DSurface9 *p;
HRESULT h;
h=Zd3d_device_ptr->CreateOffscreenPlainSurface((UINT)screen_width,(UINT)screen_height,D3DFMT_A8R8G8B8,D3DPOOL_SCRATCH,&p,NULL);
if (h != D3D_OK) 
    {
    msg("Error creating offscreen plain surface!");
    return;
    }
h=Zd3d_device_ptr->GetFrontBufferData(0,p);
if (h != D3D_OK) 
    {
    msg("Error getting front buffer data!");
    switch(h)
        {
        case D3DERR_DRIVERINTERNALERROR: msg("Driver internal error"); break;
        case D3DERR_DEVICELOST:          msg("Device lost"); break;
        case D3DERR_INVALIDCALL:         msg("Invalid call"); break;
        default:   msg("Undefined error"); break;
        }
    p->Release(); 
    return;
    }
//getstring("Screendump filename (1-8 letters)...",s);
//strcat_s(s,100,".bmp");
i=0;
do
    {
    i++;
    strcpy_s(s,100,"scrndmp");
    i2s(i,s2);
    strcat_s(s,100,s2);
    strcat_s(s,100,".bmp");
    }
    while (filefound(s));
D3DXSaveSurfaceToFile(s,D3DXIFF_BMP,p,NULL,NULL);
p->Release();
strcpy_s(s2,100,"Screendump ");
strcat_s(s2,100,s);
strcat_s(s2,100," saved.");
msg(s2);
}
 

Just to make sure I understood you correctly. The following will not execute in 1 second?

char str[16];
for (int i = 1; i <= 30; i++)
{
    sprintf(str, "D:\\%d.bmp", i);
    CaptureScreenUsingDirectX(str);
}

If this will not work, then I guess I will not learn DirectX (I was only going to learn it to do a screenshot function). Do you know of a (not too complicated) way to capture 30 screenshots in 1 second?

learn it to do a screenshot function

Do you understand that the code posted will save images only drawn by the DirectX app to its own buffer? That is, it does not "capture" the desktop, or anything drawn by anything other than the DirectX app itself.

Can you be specific about what you're trying to capture?

I don't really know anything about DirectX, I just read that DirectX can be used to do a screenshot (and it is fast at doing it).

I am trying to capture the entire desktop (i.e. Print Screen).

Hope this doesn't sound stupid, but what's your exact goal?

If you just want a screen capture of your desktop, press (ALT+)PRT SCRN and paste it in any image editor.

I am trying to write a simple screen recorder. And so I want to be able to capture a lot of screenshots in 1 second (24 fps or 30 fps).