Intercept messages from USB auxiliary device

[Gintaras]

This `_WmInput` function prints raw data. Tested with a joystick.
 

Code:

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unsafe void _WmInput(nint wParam, nint lParam) {
    //print.it("WM_INPUT");
    
    //get header
    
    int headerSize = sizeof(api.RAWINPUTHEADER), size = headerSize;
    api.RAWINPUTHEADER rih = default;
    if (api.GetRawInputData(lParam, api.RID_HEADER, &rih, ref size, headerSize) <= 0) return;
    //print.it(rih.dwType); //0 mouse, 1 keyboard, 2 other
    if (rih.dwType != 2) return;
    
    //get data
    
    var b = stackalloc byte[size = rih.dwSize];
    if (api.GetRawInputData(lParam, api.RID_INPUT, b, ref size, headerSize) <= 0) return;
    ref api.RAWINPUT raw = ref *(api.RAWINPUT*)b;
    
    //but I don't know how to read the data for non-keyboard/mouse devices. It depends on device. Ask AI.
    
    //print raw data
    
    print.it(raw.data.hid.dwCount, raw.data.hid.dwSizeHid);
    var data = raw.data.hid.bRawData.AsSpan(raw.data.hid.dwSizeHid);
    print.it(data, 8);
    print.it($"Joystick button: {data[49]}. Values of axis X and Y: {BitConverter.ToUInt32(data[1..])} {BitConverter.ToUInt32(data[5..])}.");
}

Add this line to the `api` class: internal const uint RID_HEADER = 0x10000005;

Example output:
 

Code:

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1, 65
01 00 40 00 00 00 40 00     ..@...@.
00 00 40 00 00 01 00 00     ..@.....
00 00 00 00 00 00 00 00     ........
00 00 00 00 00 00 00 00     ........
00 00 00 00 00 00 00 00     ........
00 68 30 F9 40 06 02 00     .h0.@...
00 00 00 00 00 00 00 00     ........
00 00 00 00 00 00 00 00     ........
00                          .

The data depends on device and probably is undocumented, unless it is a well-known standard device (but I don't know where it's documented). For example, when testing with a joystick, some bytes are different depending on button and axis values.