How to initialize IWICBitmapDecoder with Windows Imaging Component API - c++

Question

Actually I belive that this problem is easy to solve. It only needs a minor correction. This is the first time that I use Windows Imaging Component (WIC). I am trying to display a PNG picture in my window using Win32 or the Windows API as Microsoft likes to call it. I have written code to initialize it. It requires many steps. I have included a PNG image in my .exe file. Maybe you can look at my code to see what is missing:
void ShowImage() {
IWICBitmapDecoder** ppIDecoder;
IStream* pIStream;
HRESULT hr;
ID2D1RenderTarget* pRenderTarget;
IWICImagingFactory* pIWICFactory = 0;
PCWSTR resourceName, resourceType;
UINT destinationWidth;
UINT destinationHeight;
ID2D1Bitmap** ppBitmap;
IWICBitmapDecoder* pDecoder = NULL;
IWICBitmapFrameDecode* pSource = NULL;
IWICBitmapSource* pISource;
IWICStream* pStream = NULL;
IWICFormatConverter* pConverter = NULL;
IWICBitmapScaler* pScaler = NULL;
HRSRC imageResHandle = NULL;
HGLOBAL imageResDataHandle = NULL;
void* pImageFile = NULL;
DWORD imageFileSize = 0;
// Locate the resource. Aaahhh I should have called Makeintresource and written "PNG"
imageResHandle = FindResource(hInst, MAKEINTRESOURCE(103), L"PNG");
hr = imageResHandle ? S_OK : E_FAIL;
if (SUCCEEDED(hr)) {
// Load the resource.
imageResDataHandle = LoadResource(hInst, imageResHandle);
hr = imageResDataHandle ? S_OK : E_FAIL;
}
if (SUCCEEDED(hr)) {
// Lock it to get a system memory pointer.
pImageFile = LockResource(imageResDataHandle);
hr = pImageFile ? S_OK : E_FAIL;
}
if (SUCCEEDED(hr)) {
// Calculate the size.
imageFileSize = SizeofResource(hInst, imageResHandle);
hr = imageFileSize ? S_OK : E_FAIL;
}
// call coinitialize IWICImagingFactory
if(SUCCEEDED(hr))
hr = CoInitializeEx(0, COINIT_MULTITHREADED);
// Create WIC factory
if (SUCCEEDED(hr)) {
hr = CoCreateInstance(CLSID_WICImagingFactory,
NULL,
CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pIWICFactory)
);
}
if (SUCCEEDED(hr)) {
// Create a WIC stream to map onto the memory.
hr = pIWICFactory->CreateStream(&pStream);
}
if (SUCCEEDED(hr)) {
// Initialize the stream with the memory pointer and size.
hr = pStream->InitializeFromMemory(reinterpret_cast <BYTE*>(pImageFile),
imageFileSize);
}
if (SUCCEEDED(hr)) {
// Create a decoder for the stream.
--->hr = pIWICFactory->CreateDecoderFromStream(pStream, 0, WICDecodeMetadataCacheOnLoad, ppIDecoder);
}
}
I tried the above code which compiles without errors. All the function calls succeed except the last one that I marked with --->. Then the debugger shows a runtime exception because "The variable 'ppIDecoder' is being used without being initialized."
How do I initialize ppIDecoder?
As said, this problem should be quick to solve.