One problem about ID2D1Bitmap::CopyFromBitmap API

Question

I tried to get pixels from D2D1Bitmap1 and I have read this discussion http://social.msdn.microsoft.com/Forums/en/winappswithnativecode/thread/c9426e4c-56a0-48b6-96d1-105e9e9e581e

This is my code. 

D2D1_BITMAP_PROPERTIES1 prop = D2D1::BitmapProperties1(
		D2D1_BITMAP_OPTIONS_CPU_READ | D2D1_BITMAP_OPTIONS_CANNOT_DRAW,
		D2D1::PixelFormat(
		DXGI_FORMAT_B8G8R8A8_UNORM,
		D2D1_ALPHA_MODE_PREMULTIPLIED
		)
		);

	D2D1_SIZE_U pixelSize = m_d2dContext->GetPixelSize();
	ComPtr<ID2D1Bitmap1> otherBmp;
	DX::ThrowIfFailed(m_d2dContext->CreateBitmap(
		pixelSize, 
		nullptr,
		pixelSize.width * 4,
		&prop,
		&otherBmp
		)
	);
	
	D2D1_RECT_U rect = {0, 0, m_sInputTextProp.iBackgroundWidth, m_sInputTextProp.iBackgroundHeight};
	D2D1_POINT_2U point = {0, 0};
	DX::ThrowIfFailed(otherBmp->CopyFromBitmap(&point, outputbitmap.Get(), &rect));  
	
	D2D1_MAP_OPTIONS options = D2D1_MAP_OPTIONS_READ;
	D2D1_MAPPED_RECT mappedRect;
	DX::ThrowIfFailed(otherBmp->Map(options, &mappedRect));
	memcpy(pPixelData, mappedRect.bits, m_sInputTextProp.iBackgroundWidth * m_sInputTextProp.iBackgroundHeight * 4);
	otherBmp->Unmap();

This code can run successfully on Intel i5 IVB machine (integrated VGA) and get the correct pixels data.

But I get corrupted pixels data on AMD HD 6850 or NVIDIA 450 GTS.

I tried to use IWICImageEncoder to save it as a bitmap before I call CopyFromBitmap.

And this bitmap is correct on 3 VGA cards.

I don't know it's my code problem or does it have any possibility of VGA vendor's driver issue? 

Thanks.

Answer 1

maybe mappedRect.pitch and pich of pPixelData is incorrected;

use mappedRect.pitch

 

Answer 2

Hi Albert,

I found it's real different between mappedRect.pitch and m_sInputTextProp.iBackgroundWidth 

I modified it as 

BYTE *pSrcData = mappedRect.bits;
BYTE *pTarData = pPixelData;
for(int i = 0; i < m_sInputTextProp.iOutputBackgroundHeight; i++)
{
	memcpy(pTarData,pSrcData,m_sInputTextProp.iOutputBackgroundWidth*4);
	pTarData += m_sInputTextProp.iOutputBackgroundWidth *4;
	pSrcData += mappedRect.pitch;
}

And it's fixed.

Thank you very much.