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c++directxtransparencydirectx-11

DirectX 11 Transparency Issue

I have a png file with a transparent background.

When i draw the image the transparency works.

enter image description here

as long as there is no other transparent image in front of it as seen below.

enter image description here

What changes do i need to make to my transparency code to solve this issue?

Depth stencil code:

// Initialize the description of the depth buffer.
ZeroMemory(&depthBufferDesc, sizeof(depthBufferDesc));

// Set up the description of the depth buffer.
depthBufferDesc.Width = screenWidth;
depthBufferDesc.Height = screenHeight;
depthBufferDesc.MipLevels = 1;
depthBufferDesc.ArraySize = 1;
depthBufferDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
depthBufferDesc.SampleDesc.Count = 1;
depthBufferDesc.SampleDesc.Quality = 0;
depthBufferDesc.Usage = D3D11_USAGE_DEFAULT;
depthBufferDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
depthBufferDesc.CPUAccessFlags = 0;
depthBufferDesc.MiscFlags = 0;

// Create the texture for the depth buffer using the filled out description.
result = m_device->CreateTexture2D(&depthBufferDesc, NULL, &m_depthStencilBuffer);
Error::ErrorCheck(result, TEXT("m_device->CreateTexture2D()"));

// Initialize the description of the stencil state.
ZeroMemory(&depthStencilDesc, sizeof(depthStencilDesc));

// Set up the description of the stencil state.
depthStencilDesc.DepthEnable = true;
depthStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
depthStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;

depthStencilDesc.StencilEnable = true;
depthStencilDesc.StencilReadMask = 0xFF;
depthStencilDesc.StencilWriteMask = 0xFF;

// Stencil operations if pixel is front-facing.
depthStencilDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
depthStencilDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

// Stencil operations if pixel is back-facing.
depthStencilDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
depthStencilDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

// Create the depth stencil state.
result = m_device->CreateDepthStencilState(&depthStencilDesc, &m_depthStencilState);
Error::ErrorCheck(result, TEXT("m_device->CreateDepthStencilState()"));

// Set the depth stencil state.
m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 0);

// Initailze the depth stencil view.
ZeroMemory(&depthStencilViewDesc, sizeof(depthStencilViewDesc));

// Set up the depth stencil view description.
depthStencilViewDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
depthStencilViewDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
depthStencilViewDesc.Texture2D.MipSlice = 0;

// Create the depth stencil view.
result = m_device->CreateDepthStencilView(m_depthStencilBuffer, &depthStencilViewDesc, &m_depthStencilView);
Error::ErrorCheck(result, TEXT("m_device->CreateDepthStencilView()"));

// Bind the render target view and depth stencil buffer to the output render pipeline.
m_deviceContext->OMSetRenderTargets(1, &m_renderTargetView, m_depthStencilView);

Transparency code:

//Setup Blend State for transperency
D3D11_BLEND_DESC BlendStateDescription;
ZeroMemory(&BlendStateDescription, sizeof(D3D11_BLEND_DESC));

ID3D11BlendState* blend;

BlendStateDescription.RenderTarget[0].BlendEnable = TRUE;
BlendStateDescription.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;
BlendStateDescription.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA;

BlendStateDescription.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA;
BlendStateDescription.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_INV_DEST_ALPHA;
BlendStateDescription.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ONE;
BlendStateDescription.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;
BlendStateDescription.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;

m_device->CreateBlendState(&BlendStateDescription, &blend);
float blendFactor[] = { 0, 0, 0, 0 };
UINT sampleMask = 0xffffffff;

m_deviceContext->OMSetBlendState(blend, blendFactor, sampleMask);
Solution

  • Found the problem. Was in the depth buffer. Just a simple change depthStencilDesc.DepthFunc from D3D11_COMPARISON_LESS to D3D11_COMPARISON_LESS_EQUAL.

    Found the answer here, follow link for more detailed description: Detailed answer