func (window *Win32Window) GetHDC() unsafe.Pointer {
if window.hdc != nil {
return unsafe.Pointer(&window.hdc)
}
window.hdc = C.GetDC(window.hwnd)
px := C.PIXELFORMATDESCRIPTOR{
dwFlags: 0x00000001 | 0x00000020 | 0x00000004,
iPixelType: 0,
cColorBits: 32,
cDepthBits: 32,
iLayerType: 0,
}
px.nSize = (C.WORD)(unsafe.Sizeof(px))
pxFormat := C.ChoosePX(window.hdc, &px)
if pxFormat == 0 {
return nil
}
res := C.SetPixelFormat(window.hdc, pxFormat, &px)
if res == 0 {
return nil
}
return unsafe.Pointer(&window.hdc)
}
// 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)
}