Low level mouse hook - mouse button click vs hold - c++

Question

I'm using C++ and DirectD3D9 to draw a menu.
I wish to navigate the menu with the mouse.
I can get the mouse position, however, checking if the left button is clicked is proving tricky.
I am able to check if it is being held down, but not clicked.
bool LBUTTONDOWN = false;
LRESULT CALLBACK LowLevelMouseProc(int nCode, WPARAM wParam, LPARAM lParam) {
if (nCode == HC_ACTION && (wParam == WM_LBUTTONUP || wParam == WM_LBUTTONDOWN)) {
LBUTTONDOWN = wParam == WM_LBUTTONDOWN;
}
return CallNextHookEx(0, nCode, wParam, lParam);
}
How can I add a check to see if I clicked the left button?

Answer 1

You need to use a timing trick. Create a variable named something like 'nTime',
Set the zero for it when the LButton is up. Increase the variable value using a '+=' operator when the LButton is down and check the variable against a value something like that -
bool LBUTTONDOWN = false;
int nTime = 0;
LRESULT CALLBACK LowLevelMouseProc(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode == HC_ACTION && (wParam == WM_LBUTTONUP || wParam == WM_LBUTTONDOWN))
{
LBUTTONDOWN = wParam == WM_LBUTTONDOWN;
if ( LBUTTONDOWN )
{
nTime += 1;
if ( nTime > 1000 /*( this value depends on you )*/ )
{
nTime = 0;
// Here is your hold event code.
}
}
else
nTime = 0;
}
return CallNextHookEx(0, nCode, wParam, lParam);
}

Answer 2

There is no DoubleClick message for LowLevelMouseProc. However, I suppose you can have a work around:
Record the time interval between LBUTTONDOWN and LBUTTONUP, then to check whether it is quick enough to be a click event. And because the mouse acts very fast, it is better to set a timer for the mouse capturing.
For the mouse capturing, you can still call LowLevelMouseProc. However, the DirectInput is more convenient for processing mouse movements.
In DirectX SDK samples, there is a DirectInput sample named "CustomFormat". It shows how to set up a timer to capture mouse input.
I hope this helps.