alpha 混合无法正常工作

Question

我创建了一个新的 DirectX 项目并渲染了 2 个颜色组件，现在当我从着色器传递透明度时它没有改变任何东西，我是 c++ 和 DirectX 的新手，我使用了来自 [=39= 的标准模板] 创建项目

项目link：https://github.com/AbhishekSharma-SEG/TestAlphaBlending

混合状态

D3D11_BLEND_DESC blendDesc;
blendDesc.RenderTarget[0].BlendEnable = true;

blendDesc.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_COLOR;
blendDesc.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_COLOR;
blendDesc.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;

blendDesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_SRC_ALPHA;
blendDesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_INV_SRC_ALPHA;
blendDesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;

blendDesc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;;

blendDesc.IndependentBlendEnable = false;
blendDesc.AlphaToCoverageEnable = false;

auto hr = m_d3dDevice->CreateBlendState(&blendDesc, &AlphaEnableBlendingState);
if (SUCCEEDED(hr)) 
{
    blendDesc.RenderTarget[0].BlendEnable = false;
    m_d3dDevice->CreateBlendState(&blendDesc, &AlphaDisableBlendingState);
    TurnOnAlphaBlending();
}
}
void DX::DeviceResources::TurnOnAlphaBlending()
{
    float input[4] = { 0,0,0,0 };
    m_d3dContext->OMSetBlendState(AlphaEnableBlendingState, input, 1);
}
void DX::DeviceResources::TurnOffAlphaBlending()
{
    float input[4] = { 0,0,0,0 };
    m_d3dContext->OMSetBlendState(AlphaDisableBlendingState, input, 1);
}

交换链描述

// Otherwise, create a new one using the same adapter as the existing Direct3D device.
DXGI_SCALING scaling = DisplayMetrics::SupportHighResolutions ? DXGI_SCALING_NONE : DXGI_SCALING_STRETCH;
DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {0};

swapChainDesc.Width = lround(m_d3dRenderTargetSize.Width);      // Match the size of the window.
swapChainDesc.Height = lround(m_d3dRenderTargetSize.Height);
swapChainDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;              // This is the most common swap chain format.
swapChainDesc.Stereo = false;
swapChainDesc.SampleDesc.Count = 1;                             // Don't use multi-sampling.
swapChainDesc.SampleDesc.Quality = 0;
swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
swapChainDesc.BufferCount = 2;                                  // Use double-buffering to minimize latency.
swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;    // All Microsoft Store apps must use _FLIP_ SwapEffects.
swapChainDesc.Flags = 0;
swapChainDesc.Scaling = scaling;
swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;

着色器

struct PixelShaderInput
{
    float4 pos : SV_POSITION;
    float3 color : COLOR0;
};

float4 main(PixelShaderInput input) : SV_TARGET
{
    return float4(input.color, 0.2f);
}

输出

我找不到问题所在，几个教程和网站只讲述了如何设置混合状态，我尝试了他们告诉我应用的大部分设置，但它不起作用我也不知道为什么黄色组件应该在后面，因为首先出现对黄色组件的渲染调用，但它打印在红色组件上方，如果有人可以提供帮助，请感谢

alpha 模式忽略后的新输出并按照直线设置混合模式

编辑：已修复

所以在一些挖掘之后，我发现我没有使用深度模板状态，它在使用它解决后导致了这个问题，显然感谢@chukWalbourn 的建议，我能够设置混合的写入配置现在它工作得很好这里是帮助它的变化

//Describe our Depth/Stencil Buffer
CD3D11_DEPTH_STENCIL_DESC depthStencilStateDesc;

depthStencilStateDesc.DepthEnable = false;
depthStencilStateDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
depthStencilStateDesc.DepthFunc = D3D11_COMPARISON_LESS;
depthStencilStateDesc.StencilEnable = true;
depthStencilStateDesc.StencilReadMask = 0xFF;
depthStencilStateDesc.StencilWriteMask = 0xFF;
depthStencilStateDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
depthStencilStateDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;
depthStencilStateDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
depthStencilStateDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

DX::ThrowIfFailed(
    m_d3dDevice->CreateDepthStencilState(
        &depthStencilStateDesc, 
        &m_d3dDepthStencilState
    )
);

m_d3dContext->OMSetDepthStencilState(m_d3dDepthStencilState.Get(), 1);

Answer 1

当将 DXGI swap-chain alpha 模式用作 Direct3D 渲染目标时，UWP 应设置为 DXGI_ALPHA_MODE_IGNORE 或 Win32 应设置为 DXGI_ALPHA_MODE_UNSPECIFIED。这仅适用于某些 Direct2D / DirectComposition-related 场景。

对于straight-alpha，使用：

D3D11_BLEND_DESC blendDesc = {};
blendDesc.RenderTarget[0].BlendEnable = TRUE;
blendDesc.RenderTarget[0].SrcBlend =
blendDesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_SRC_ALPHA;
blendDesc.RenderTarget[0].DestBlend =
blendDesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_INV_SRC_ALPHA;
blendDesc.RenderTarget[0].BlendOp =
blendDesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
blendDesc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;

对于预乘 alpha 使用：

D3D11_BLEND_DESC blendDesc = {};
blendDesc.RenderTarget[0].BlendEnable = TRUE;
blendDesc.RenderTarget[0].SrcBlend =
blendDesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE;
blendDesc.RenderTarget[0].DestBlend =
blendDesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_INV_SRC_ALPHA;
blendDesc.RenderTarget[0].BlendOp =
blendDesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
blendDesc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;

'additive' 混合使用：

D3D11_BLEND_DESC blendDesc = {};
blendDesc.RenderTarget[0].BlendEnable = TRUE;
blendDesc.RenderTarget[0].SrcBlend =
blendDesc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_SRC_ALPHA;
blendDesc.RenderTarget[0].DestBlend =
blendDesc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ONE;
blendDesc.RenderTarget[0].BlendOp =
blendDesc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
blendDesc.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;

You may want to take a look at DirectX Tool Kit.

Answer 2

所以在一些挖掘之后，我发现我没有使用深度模板状态，它在使用它后解决了这个问题，显然感谢@chukWalbourn 的建议，我能够设置混合的写入配置现在它完全正常了这里是帮助它的变化

//Describe our Depth/Stencil Buffer
CD3D11_DEPTH_STENCIL_DESC depthStencilStateDesc;

depthStencilStateDesc.DepthEnable = false;
depthStencilStateDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
depthStencilStateDesc.DepthFunc = D3D11_COMPARISON_LESS;
depthStencilStateDesc.StencilEnable = true;
depthStencilStateDesc.StencilReadMask = 0xFF;
depthStencilStateDesc.StencilWriteMask = 0xFF;
depthStencilStateDesc.FrontFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.FrontFace.StencilDepthFailOp = D3D11_STENCIL_OP_INCR;
depthStencilStateDesc.FrontFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.FrontFace.StencilFunc = D3D11_COMPARISON_ALWAYS;
depthStencilStateDesc.BackFace.StencilFailOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.BackFace.StencilDepthFailOp = D3D11_STENCIL_OP_DECR;
depthStencilStateDesc.BackFace.StencilPassOp = D3D11_STENCIL_OP_KEEP;
depthStencilStateDesc.BackFace.StencilFunc = D3D11_COMPARISON_ALWAYS;

DX::ThrowIfFailed(
    m_d3dDevice->CreateDepthStencilState(
        &depthStencilStateDesc, 
        &m_d3dDepthStencilState
    )
);

m_d3dContext->OMSetDepthStencilState(m_d3dDepthStencilState.Get(), 1);

alpha 混合无法正常工作

alpha blending is not working as it supposed to be

c++

directx

3d

uwp