DirectX surface size in windowed mode, and testing whether a directX surface is present.

[erikvullings]

Hi,

I am currently using your great program to capture screenshots from DirectX devices like VLC or a game. As I am no DirectX expert, I wonder if you can help me with two issues:

• When selecting the program to hook, I can enter the name of a program that has no DirectX support (e.g. notepad). This causes your program to stop responding. Do you know how I can test whether a program runs under DirectX (so I should be able to inject)?
• When the captured program is running in windowed mode, what is the size of the visible DirectX surface? E.g. when I capture VLC, its size also contains the Window frame, and is therefore larger than the actual display surface.

Finally, as you are also the author of Easyhook, I wonder if it is possible to remove the hook injected via Easyhook? And is there a way to test whether an application is already hooked (or if I try to hook an app twice, will it only be hooked once)?

Thanks for any help you can give me! Erik

[chenboo]

1： use GetModuleHandle to know whether a application have already loaded "directx dll",if the function return value is not null,it mean this application doesn't use diretx. 2: u can use any hook method to hook (e.g. detours, mhook.),and hook shouldn't affect other existing hook .

[justinstenning]

Erik,

As chenboo said, use GetModuleHandle to determine if DX is loaded. This is in fact already happening in this project, it probably just needs a Thread.Sleep(100); at the end of the Run method to give the IPC time to deal with anything before exiting if no DX is loaded.

The Hooks can be removed by calling .Dispose() on the local hook instance. You cannot unload the .NET assemblies unless EasyHook is modified to create its own AppDomain. You can hook the same function multiple times, however its best to dispose of the hooks properly.

[justinstenning]

Regarding VLC - the size discrepancy is fairly unique to that application. I have had to modify the capture region in the past to deal with this exact issue with it.

[chenboo]

when the 'Present" is hooked,do u try to get backbuffer,and get the TEXTURE2D_DESC of the backbuffer to know the size?

[justinstenning]

When I retrieve the render target I then access the "Description" structure (which in this case I think will be a D3DSURFACE_DESC):

e.g.

using (Surface renderTargetTemp = device.GetRenderTarget(0)) { int width, height; width = renderTargetTemp.Description.Width; height = renderTargetTemp.Description.Height; }

The above is taken from DXHookD3D9.cs

[chenboo]

:+1: now i am off work,hava a nice day @spazzarama

[chenboo]

@spazzarama do u try to hook dwm.exe in win8? in win7,as we know,dwm.exe use dxgi to manage desktop.and when i hook the "Present" in dxgi.dll,i can capture the screen by get backbuffer. in win8,some guys say ,win8 cancle areo glass,means hook present can't get the backbuffer like i do in win7. after using windbg debug win8.i bp "" because i find this function is always called by dwm.exe.

[chenboo]

dxgi!CDXGISwapChain[::IDXGISwapChainDWM1]::Present1......

[justinstenning]

@chenboo - could you post a Gist or example here of the code you use to capture from DWM in Win7/8? Btw I've just uploaded a large changeset with major restructure of code and major changes (e.g. using SharpDX instead of SlimDX and so on).