func main(f func(screen.Screen)) (retErr error) {
// It does not matter which OS thread we are on.
// All that matters is that we confine all UI operations
// to the thread that created the respective window.
runtime.LockOSThread()
hr := C.initUtilityWindow()
if hr != C.S_OK {
return winerror("failed to create utility window", hr)
}
defer func() {
// TODO(andlabs): log an error if this fails?
C.DestroyWindow(C.utilityWindow)
// TODO(andlabs): unregister window class
}()
hr = C.initWindowClass()
if hr != C.S_OK {
return winerror("failed to create Window window class", hr)
}
// TODO(andlabs): uninit
s := newScreenImpl()
go f(s)
C.mainMessagePump()
return nil
}
func (wi *windowInternal) close() ThreadError {
// Destroy the custom icon, if any
if wi.icon != nil {
C.DestroyIcon(wi.icon)
}
if wi.callback == nil {
// Destroy the window
if wi.window.IsValid() {
C.DestroyWindow(wi.window.Handle)
}
} else {
// The window is external : remove the hook on its message callback
C.__SetWindowLongPtr(wi.window.Handle, C.GWLP_WNDPROC, wi.callback)
}
return nil
}
func (ic *contextInternal) close() ThreadError {
// start by waiting for deactivation to finish
<-ic.deactivateSignal
// Destroy the OpenGL context
if ic.context != nil {
C.wglDeleteContext(ic.context)
}
// Destroy the device context
if ic.hdc != nil {
C.ReleaseDC(ic.window, ic.hdc)
}
// Destroy the window if we own it
if ic.window != nil && ic.ownsWindow {
C.DestroyWindow(ic.window)
}
return nil
}