Reading the 360 pad's Guide button

gistfile1.cpp

// Part of button_on_360_guide by https://github.com/pinumbernumber
// Distributed under the highly permissive WTFPL, see COPYING.txt

// Untested, not even compiled. I don't have a Windows machine handy.

using namespace std;

#include <windows.h>

// We don't need all of XInput so no need to require the official headers.
// Just redefine stuff here.
typedef struct
{
	WORD  wButtons;
	BYTE  bLeftTrigger;
	BYTE  bRightTrigger;
	SHORT sThumbLX;
	SHORT sThumbLY;
	SHORT xThumbRX;
	SHORT xThumbRY;
} XINPUT_GAMEPAD;

typedef struct
{
	DWORD          dwPacketNumber;
	XINPUT_GAMEPAD Gamepad;
} XINPUT_STATE;

#define ERROR_DEVICE_NOT_CONNECTED 1167
#define XINPUT_GAMEPAD_GUIDE 0x0400

// For cleaner syntax, define XInputGetStateEx_t as a function
// returning DWORD and accepting a DWORD and an XINPUT_STATE*
typedef DWORD (__stdcall *XInputGetStateEx_t) (DWORD, XINPUT_STATE*);

int main()
{
	// Try to load 1.4 (Windows 8)
	HINSTANCE xinputDll = LoadLibrary("xinput1_4.dll");
	if (!xinputDll)
	{
		// Try to load 1.3 (Windows <8)
		xinputDll = LoadLibrary("xinput1_3.dll");
			if (!xinputDll)
			{
				// Still nothing? You should probably exit with a fatal error here.
			}
	}
	
	// Load the actual function. C++ requires an ugly cast here, what can you do...
	// The function isn't exported with a name but we can still import it by ordinal
	// using a strange cast of an integer to a string.
	XInputGetStateEx_t XInputGetStateEx = (XInputGetStateEx_t) GetProcAddress(xinputDll, (LPCSTR)100);

	// Only consider one player for now.
	XINPUT_STATE playerOneState;
	ZeroMemory(&playerOneState, sizeof(XINPUT_STATE)); // This might or mightn't be neccesary. No harm in it anyway.

	// Infinite loop. You'd want a Sleep() command or something somehwere in it to avoid
	// consuming all CPU time.
	while(1)
	{
		// 0 as in player one. Do it in a conditional since the return value
		// indicates connectivity.
		if (XInputGetStateEx(0, &playerOneState) == ERROR_DEVICE_NOT_CONNECTED)
		{
			// The pad is disconnected.
		}
		else
		{
			// Pad's connected. Is guide down?
			if (playerOneState.Gamepad.wButtons & XINPUT_GAMEPAD_GUIDE)
			{
				// Yep!
				// Only shows whether it's down right now, of course, not whether it
				// was just pressed. I kept variables indicating the previous state
				// and compared with them.
			}
		}
	}
}