Direct2D Loading and Drawing Bitmap - c++

Question

I'm trying to draw a bitmap to the screen; the code that calls to load the bitmap from a file works, but it seems the actual drawing part is causing some program crashes.
I followed a tutorial from MSDN, but the only change I made was instead of using ID2D1RenderTarget, I'm using a ID2D1DCRenderTarget.
Here's the Load method that works:
HRESULT LoadBitmapFromFile(
ID2D1DCRenderTarget *pRenderTarget,
IWICImagingFactory *pIWICFactory,
PCWSTR uri,
UINT destinationWidth,
UINT destinationHeight,
ID2D1Bitmap **ppBitmap
)
{
IWICBitmapDecoder *pDecoder = NULL;
IWICBitmapFrameDecode *pSource = NULL;
IWICStream *pStream = NULL;
IWICFormatConverter *pConverter = NULL;
IWICBitmapScaler *pScaler = NULL;
HRESULT hr = pIWICFactory->CreateDecoderFromFilename(
uri,
NULL,
GENERIC_READ,
WICDecodeMetadataCacheOnLoad,
&pDecoder
);
if (SUCCEEDED(hr))
{
// Create the initial frame.
hr = pDecoder->GetFrame(0, &pSource);
}
if (SUCCEEDED(hr))
{
// Convert the image format to 32bppPBGRA
// (DXGI_FORMAT_B8G8R8A8_UNORM + D2D1_ALPHA_MODE_PREMULTIPLIED).
hr = pIWICFactory->CreateFormatConverter(&pConverter);
}
if (SUCCEEDED(hr))
{
// If a new width or height was specified, create an
// IWICBitmapScaler and use it to resize the image.
if (destinationWidth != 0 || destinationHeight != 0)
{
UINT originalWidth, originalHeight;
hr = pSource->GetSize(&originalWidth, &originalHeight);
if (SUCCEEDED(hr))
{
if (destinationWidth == 0)
{
FLOAT scalar = static_cast<FLOAT>(destinationHeight) / static_cast<FLOAT>(originalHeight);
destinationWidth = static_cast<UINT>(scalar * static_cast<FLOAT>(originalWidth));
}
else if (destinationHeight == 0)
{
FLOAT scalar = static_cast<FLOAT>(destinationWidth) / static_cast<FLOAT>(originalWidth);
destinationHeight = static_cast<UINT>(scalar * static_cast<FLOAT>(originalHeight));
}
hr = pIWICFactory->CreateBitmapScaler(&pScaler);
if (SUCCEEDED(hr))
{
hr = pScaler->Initialize(
pSource,
destinationWidth,
destinationHeight,
WICBitmapInterpolationModeCubic
);
}
if (SUCCEEDED(hr))
{
hr = pConverter->Initialize(
pScaler,
GUID_WICPixelFormat32bppPBGRA,
WICBitmapDitherTypeNone,
NULL,
0.f,
WICBitmapPaletteTypeMedianCut
);
}
}
}
else // Don't scale the image.
{
hr = pConverter->Initialize(
pSource,
GUID_WICPixelFormat32bppPBGRA,
WICBitmapDitherTypeNone,
NULL,
0.f,
WICBitmapPaletteTypeMedianCut
);
}
}
if (SUCCEEDED(hr))
{
// Create a Direct2D bitmap from the WIC bitmap.
hr = pRenderTarget->CreateBitmapFromWicBitmap(
pConverter,
NULL,
ppBitmap
);
}
if (pDecoder) pDecoder->Release();
if (pSource) pSource->Release();
if (pStream) pStream->Release();
if (pScaler) pScaler->Release();
return hr;
}
And in between the BeginDraw() and EndDraw() for the render target, I have the following code to draw the bitmap. This is the part that crashes the program when I attempt to run it:
d2dg->pRT->BeginDraw();
// Create a WIC Factory
HRESULT hr = CoCreateInstance(
CLSID_WICImagingFactory,
NULL,
CLSCTX_INPROC_SERVER,
IID_IWICImagingFactory,
(LPVOID*)&wicFactory);
hr = LoadBitmapFromFile(d2dg->pRT, wicFactory, L"image1.png", 400, 400, &pBitmap);
D2D1_SIZE_F size = pBitmap->GetSize();
D2D1_POINT_2F upperLeftCorner = D2D1::Point2F(100.f, 10.f);
// Draw a bitmap.
d2dg->pRT->DrawBitmap(
pBitmap,
D2D1::RectF(
upperLeftCorner.x,
upperLeftCorner.y,
upperLeftCorner.x + size.width,
upperLeftCorner.y + size.height)
);
d2dg->pRT->EndDraw();

Answer 1

Found the issue to this: the bitmap I wanted to draw was still NULL.
This can be fixed by deleting the ID2D1Bitmap **ppBitmap parameter from LoadBitmapFromFile and just work with the pointer to &pBitmap for any references to a bitmap within the method.
That way, pBitmap gets manipulated and will not remain NULL.