# DX11 Alpha Transparency DX11

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Hello everybody, it has been a while since I have asked a question on these forums. Currently I am loading in images that I wish to make the alpha channel transparent when drawing my scene. Here is how i create my blenddesc

 D3D11_BLEND_DESC blendDesc; ZeroMemory( &blendDesc, sizeof( blendDesc ) ); blendDesc.RenderTarget[0].BlendEnable = true; blendDesc.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA; blendDesc.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA; blendDesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_SRC_ALPHA; blendDesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_INV_SRC_ALPHA; blendDesc.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD; blendDesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD; blendDesc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL; float blendFactor[4] = { 0.0f, 0.0f, 0.0f, 0.0f }; m_d3dDevice->CreateBlendState( &blendDesc, &alphaBlendState_ ); m_d3dContext->OMSetBlendState( alphaBlendState_, blendFactor, 0xFFFFFFFF ); 

I cannot figure out why the green "grass" on the bottom is slightly transparent and the blue "clouds" at the top are not.

 float4 PS_Main( PS_Input frag ) : SV_TARGET { return colorMap_.Sample( colorSampler_, frag.tex0 ); } 

I have tried messing around with the blenddesc a LOT and if I make one change it messes up what im trying to get. Am I missing something completely obvious here?

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So I figured out the blue is just too opaque to see through, if I change the color to something lighter it is all partially transparent.

EDIT:

Alright, so apparently irfanview when saving png images makes you select a color to make transparent. It makes that color plus everything else slightly transparent. I opened the images and edited them in photoshop and everything is looking good now.

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• By Stewie.G
Hi,
I've been trying to implement a gaussian blur recently, it would seem the best way to achieve this is by running a bur on one axis, then another blur on the other axis.
I think I have successfully implemented the blur part per axis, but now I have to blend both calls with a proper BlendState, at least I think this is where my problem is.
Here are my passes:
D3DX11_TECHNIQUE_DESC techDesc; mBlockEffect->mTech->GetDesc( &techDesc ); for(UINT p = 0; p < techDesc.Passes; ++p) { deviceContext->IASetVertexBuffers(0, 2, bufferPointers, stride, offset); deviceContext->IASetIndexBuffer(mIB, DXGI_FORMAT_R32_UINT, 0); mBlockEffect->mTech->GetPassByIndex(p)->Apply(0, deviceContext); deviceContext->DrawIndexedInstanced(36, mNumberOfActiveCubes, 0, 0, 0); } No blur

PS_BlurV

PS_BlurH

P0 + P1

As you can see, it does not work at all.
I think the issue is in my BlendState, but I am not sure.
I've seen many articles going with the render to texture approach, but I've also seen articles where both shaders were called in succession, and it worked just fine, I'd like to go with that second approach. Unfortunately, the code was in OpenGL where the syntax for running multiple passes is quite different (http://rastergrid.com/blog/2010/09/efficient-gaussian-blur-with-linear-sampling/). So I need some help doing the same in HLSL :-)

Thanks!