func (ic *contextInternal) initializeFromSettings(settings ContextSettings, width, height int) ThreadError {
ic.deactivateSignal = make(chan bool)
ic.settings = settings
ic.window = createHiddenWindow(width, height)
if ic.window == nil {
// C.GetLastError()
return NewThreadError(fmt.Errorf("could not create window (%d)", C.GetLastError()), true)
}
ic.ownsWindow = true
ic.hdc = C.GetDC(ic.window)
if ic.hdc == nil {
return NewThreadError(errors.New("no device context"), true)
}
if sharedContext == nil { // if there is no shared context, we are it
ic.isSharedContext = true
pfd := C.PIXELFORMATDESCRIPTOR{
nSize: C.PIXELFORMATDESCRIPTOR_size, // size of this pfd
nVersion: 1, // version number
iPixelType: C.PFD_TYPE_RGBA, // RGBA type
cColorBits: 24, // 24-bit color depth
cDepthBits: 32, // 32-bit z-buffer
iLayerType: C.PFD_MAIN_PLANE, // main layer
// support window | OpenGL | double buffer
dwFlags: C.PFD_DRAW_TO_WINDOW | C.PFD_SUPPORT_OPENGL | C.PFD_DOUBLEBUFFER,
}
// get the best available match of pixel format for the device context
// make that the pixel format of the device context
if iPixelFormat := C.ChoosePixelFormat(ic.hdc, &pfd); iPixelFormat == 0 {
return NewThreadError(fmt.Errorf("sharedContext: ChoosePixelFormat failed (%d)", C.GetLastError()), true)
} else if C.SetPixelFormat(ic.hdc, iPixelFormat, &pfd) == C.FALSE {
return NewThreadError(fmt.Errorf("sharedContext: SetPixelFormat failed (%d)", C.GetLastError()), true)
}
ic.context = C.wglCreateContext(ic.hdc)
if ic.context == nil {
return NewThreadError(fmt.Errorf("sharedContext: wglCreateContext failed (%d)", C.GetLastError()), true)
}
} else { // otherwise we push the commands onto the shared context thread
bitsPerPixel := GetDefaultMonitor().GetDesktopMode().BitsPerPixel
ic.context = createContext(&sharedContext.internal.procs, sharedContext.internal.context, ic.hdc, bitsPerPixel, &ic.settings)
if ic.context == nil {
return NewThreadError(fmt.Errorf("could not create context (%d)", C.GetLastError()), true)
}
}
// signal because we start out deactivated
ic.signalDeactivation()
return nil
}
// Find a pixel format with no antialiasing, if not needed or not supported
func BestChoosePixelFormat(hdc C.HDC, bitsPerPixel uint, settings *ContextSettings) C.int {
// Setup a pixel format descriptor from the rendering settings
descriptor := C.PIXELFORMATDESCRIPTOR{
nSize: C.PIXELFORMATDESCRIPTOR_size,
nVersion: 1,
iLayerType: C.PFD_MAIN_PLANE,
dwFlags: C.PFD_DRAW_TO_WINDOW | C.PFD_SUPPORT_OPENGL | C.PFD_DOUBLEBUFFER,
iPixelType: C.PFD_TYPE_RGBA,
cColorBits: C.BYTE(bitsPerPixel),
cDepthBits: C.BYTE(settings.DepthBits),
cStencilBits: C.BYTE(settings.StencilBits),
}
if bitsPerPixel == 32 {
descriptor.cAlphaBits = 8
}
// Get the pixel format that best matches our requirements
return C.ChoosePixelFormat(hdc, &descriptor)
}