Windows 8 Store App DirectX 11.1 Enabling Blendstate with loaded PNG texture with alpha

问题

I am loading a PNG with transparency to a texture with the following code:

ComPtr<IWICStream> stream;
ComPtr<IWICBitmapDecoder> bitmapDecoder;
ComPtr<IWICBitmapFrameDecode> bitmapFrame;
ComPtr<IWICFormatConverter> formatConverter;
unsigned int width, height
D3D11_SUBRESOURCE_DATA resourceData;

ZeroMemory(&resourceData, sizeof(resourceData));

DX::ThrowIfFailed( m_wicFactory->CreateStream(&stream) );
DX::ThrowIfFailed( stream->InitializeFromMemory( rawFileBytes->Data, rawFileBytes->Length) );
DX::ThrowIfFailed( m_wicFactory->CreateDecoderFromStream( stream.Get(), nullptr, WICDecodeMetadataCacheOnDemand, &bitmapDecoder ) );
DX::ThrowIfFailed( bitmapDecoder->GetFrame(0, &bitmapFrame) );
DX::ThrowIfFailed( m_wicFactory->CreateFormatConverter(&formatConverter) );
DX::ThrowIfFailed( formatConverter->Initialize( bitmapFrame.Get(), GUID_WICPixelFormat32bppPBGRA, WICBitmapDitherTypeNone, nullptr, 1.0f /* some docs set this to 0.0f */, WICBitmapPaletteTypeCustom ) );
DX::ThrowIfFailed( bitmapFrame->GetSize(&width, &height) );

std::unique_ptr<byte[]> bitmapPixels(new byte[width * height * 4]);
DX::ThrowIfFailed( formatConverter->CopyPixels( nullptr, width * 4, width * height * 4, bitmapPixels.get() ) );

resourceData.pSysMem = bitmapPixels.get();
resourceData.SysMemPitch = width * 4;
resourceData.SysMemSlicePitch = 0;

CD3D11_TEXTURE2D_DESC textureDesc( DXGI_FORMAT_B8G8R8A8_UNORM, width, height, 1, 1 );
DX::ThrowIfFailed( m_d3dDevice->CreateTexture2D( &textureDesc, &resourceData, &texture2D ) );

if ( textureView != nullptr ) {
  CD3D11_SHADER_RESOURCE_VIEW_DESC shaderResourceViewDesc( texture2D.Get(), D3D11_SRV_DIMENSION_TEXTURE2D );
  DX::ThrowIfFailed( m_d3dDevice->CreateShaderResourceView( texture2D.Get(), &shaderResourceViewDesc, &shaderResourceView ) );
}

And to set up my blend state in a different section of code:

Microsoft::WRL::ComPtr<ID3D11BlendState1> blendState;

D3D11_BLEND_DESC1 desc;
ZeroMemory( &desc, sizeof( desc ) );
desc.IndependentBlendEnable = FALSE;
desc.AlphaToCoverageEnable = FALSE;
desc.RenderTarget[0].BlendEnable = TRUE;
desc.RenderTarget[0].LogicOpEnable = FALSE;
desc.RenderTarget[0].SrcBlend = D3D11_BLEND::D3D11_BLEND_SRC_ALPHA;
desc.RenderTarget[0].DestBlend = D3D11_BLEND::D3D11_BLEND_INV_SRC_ALPHA;
desc.RenderTarget[0].BlendOp = D3D11_BLEND_OP::D3D11_BLEND_OP_ADD;
desc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND::D3D11_BLEND_ONE;
desc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND::D3D11_BLEND_ONE;
desc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP::D3D11_BLEND_OP_ADD;
desc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;

direct3d.device->CreateBlendState1( &desc, blendState.GetAddressOf() );
direct3d.context->OMSetBlendState( blendState.Get(), NULL, 0xffffffff );

With all this setup, I still get black backgrounds where there should be alpha.

Clarification: I have a set of 48 square panels that are being overlayed on each other from z 0.0f to 48.0f, but all I can see is the very front 48.0f texture. Rather than the transparent zones being transparent, they are being rendered as black.

Edit: Here is my pixel shader:

Texture2D Texture : register(t0);
SamplerState Sampler : register(s0);

struct sPSInput
{
    float4 pos : SV_POSITION;
    float3 norm : NORMAL;
    float2 tex : TEXCOORD0;
};

float4 SimplePixelShader(sPSInput input) : SV_TARGET
{
  float4 textured = Texture.Sample(Sampler, input.tex);
  return textured;
}

回答1:

This

    desc.RenderTarget[0].SrcBlend = D3D11_BLEND::D3D11_BLEND_ONE;

should be this

   desc.RenderTarget[0].SrcBlend = D3D11_BLEND::D3D11_BLEND_ALPHA;

also AlphaToCoverageEnable should be set false for your needs

Furthermore you have to disable the Z buffer. The enabled Z buffer prevents all objects behind the object in front to be drawn.

回答2:

You need to normalize your Z-values to the range 0.0f (near) - 1.0f (far).

Are you setting up your ViewPort properly?

D3D11_VIEWPORT Viewport =
{
    0.0f,                           // TopLeftX
    0.0f,                           // TopLeftY
    <width>,                        // Width
    <height>,                       // Height
    0.0f,                           // MinDepth
    1.0f };                         // MaxDepth

来源：https://stackoverflow.com/questions/14859018/windows-8-store-app-directx-11-1-enabling-blendstate-with-loaded-png-texture-wit

标签

windows-8

windows-store-apps

directx-11

alphablending

c++-cx