Direct3D Initialization - Introduction to 3D Game Programming with DirectX 9.0 - page 53

t=0;

}

}

}

InitD3D —This function initializes a main application window and
implements the Direct3D initialization code discussed in section
1.4. It outputs a pointer to a created IDirect3DDevice9 inter-
face if the function returns successfully. Observe that the parame-
ters allow us to specify the window's dimensions and whether it
should run in windowed mode or full-screen mode. See the sample
code for further details on its implementation.

EnterMsgLoop —This function wraps the application message
loop. It takes a pointer to a function that is to be the display func-
tion . The display function is the function that implements the sam-
ple's drawing code. The message loop function needs to know the
display function so that it can call it and display the scene during
idle processing:
int d3d::EnterMsgLoop( bool (*ptr_display)(float timeDelta) )
{

MSG msg;
::ZeroMemory(&msg, sizeof(MSG));

static float lastTime = (float)timeGetTime();

while(msg.message != WM_QUIT)
{

if(::PeekMessage(&msg, 0, 0, 0, PM_REMOVE))
{

::TranslateMessage(&msg);
::DispatchMessage(&msg);

}
else
{

float currTime = (float)timeGetTime();
float timeDelta = (currTime -
lastTime)*0.001f;

ptr_display(timeDelta); // call display function

lastTime = currTime;

}

}
return msg.wParam;

}
The “time” code is used to calculate the time elapsed between calls
to ptr_display , that is, the time between frames.

Release —This template function is designed as a convenience
function to release COM interfaces and set them to null.