Question

我一直在为游戏制作3D渲染器，直到现在它首先渲染所有无纹理网格，然后使用DrawIndexed渲染所有纹理网格。为了提高性能，我已经切换到DrawIndexedInstanced并使其首先渲染纹理网格，这表明我的alpha混合和/或深度检查是如何设置的。以下图片应说明问题所在：

View through the top of the front-most textures (textured meshes rendered first)

The same view, slightly different angle (textureless meshes rendered first)

在前景和背景中是纹理矩形网格的行，而前景中的网格具有部分透明的网格。在中间行是无纹理的网格，其透明度设置为0.3f。首先渲染纹理网格时，前景中的透明网格会遮挡未纹理的网格。然而，当它是首先渲染的无纹理网格时，它们完全掩盖了它们后面的纹理网格，即使它们的透明度为0.3f。当无纹理网格遮盖其他无纹理网格时，这种情况不会发生，alpha混合在该场景中正常工作。

这是我设置光栅化器状态，深度模板状态和深度模板视图的地方：

ID3D11Texture2D *pBackBuffer;
D3D11_TEXTURE2D_DESC backBufferDesc;
m_swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);
pBackBuffer->GetDesc(&backBufferDesc);
RELEASE_RESOURCE(pBackBuffer);

// creating a buffer for the depth stencil
D3D11_TEXTURE2D_DESC depthStencilBufferDesc;
ZeroMemory(&depthStencilBufferDesc, sizeof(D3D11_TEXTURE2D_DESC));

depthStencilBufferDesc.ArraySize = 1;
depthStencilBufferDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
depthStencilBufferDesc.CPUAccessFlags = 0; // No CPU access required.
depthStencilBufferDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
depthStencilBufferDesc.Width = backBufferDesc.Width;
depthStencilBufferDesc.Height = backBufferDesc.Height;
depthStencilBufferDesc.MipLevels = 1;
depthStencilBufferDesc.SampleDesc.Count = 4;
depthStencilBufferDesc.SampleDesc.Quality = 0;
depthStencilBufferDesc.Usage = D3D11_USAGE_DEFAULT;
m_device->CreateTexture2D(&depthStencilBufferDesc, NULL, &m_depthStencilBuffer);

// creating a depth stencil view
HRESULT hr = m_device->CreateDepthStencilView(  m_depthStencilBuffer,
                                                NULL,   
                                                &m_depthStencilView);


// setup depth stencil state.
D3D11_DEPTH_STENCIL_DESC depthStencilStateDesc;
ZeroMemory(&depthStencilStateDesc, sizeof(D3D11_DEPTH_STENCIL_DESC));

depthStencilStateDesc.DepthEnable = TRUE;
depthStencilStateDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
depthStencilStateDesc.DepthFunc = D3D11_COMPARISON_LESS;
depthStencilStateDesc.StencilEnable = FALSE;

hr = m_device->CreateDepthStencilState(&depthStencilStateDesc, &m_depthStencilState);

// setup rasterizer state.
D3D11_RASTERIZER_DESC rasterizerDesc;
ZeroMemory(&rasterizerDesc, sizeof(D3D11_RASTERIZER_DESC));

rasterizerDesc.AntialiasedLineEnable = FALSE;
rasterizerDesc.CullMode = D3D11_CULL_BACK;
rasterizerDesc.DepthBias = 0;
rasterizerDesc.DepthBiasClamp = 0.0f;
rasterizerDesc.DepthClipEnable = TRUE;
rasterizerDesc.FillMode = D3D11_FILL_SOLID;
rasterizerDesc.FrontCounterClockwise = FALSE;
rasterizerDesc.MultisampleEnable = FALSE;
rasterizerDesc.ScissorEnable = FALSE;
rasterizerDesc.SlopeScaledDepthBias = 0.0f;

// create the rasterizer state
hr = m_device->CreateRasterizerState(&rasterizerDesc, &m_RasterizerState);

m_deviceContext->OMSetRenderTargets(1, &m_renderTargetView, m_depthStencilView);
m_deviceContext->OMSetDepthStencilState(m_depthStencilState, 1);
m_deviceContext->RSSetState(m_RasterizerState);

这就是我启用alpha混合的地方：

D3D11_BLEND_DESC blendDescription;
ZeroMemory(&blendDescription, sizeof(D3D11_BLEND_DESC));
blendDescription.RenderTarget[0].BlendEnable = TRUE;
blendDescription.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA;
blendDescription.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA;
blendDescription.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;
blendDescription.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE;
blendDescription.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO;
blendDescription.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
blendDescription.RenderTarget[0].RenderTargetWriteMask = D3D11_COLOR_WRITE_ENABLE_ALL;
m_device->CreateBlendState(&blendDescription, &m_blendState);
m_deviceContext->OMSetBlendState(m_blendState, 0, 0xffffffff);

我知道给无纹理网格提供纯白色完全不透明的纹理会以某种方式解决问题，但我怀疑深度测试是错误的。

当我使用D3D11_CREATE_DEVICE_DEBUG标志创建设备时，它不会给我任何错误或警告。

Create函数返回的所有HRESULT都是S_OK。

提前致谢。

Answer 1

要使混合工作，您必须首先渲染所有完全不透明的对象，然后以前后顺序渲染所有具有透明度的对象。这意味着您的透明对象将根据距离相机的距离进行排序。

理想情况下，您的不透明对象按相反方向（从前到后）排序，以便深度测试会丢弃被遮挡的像素。

这通常通过将所有绘制请求放入队列来完成。一旦场景中的所有内容都在队列中，您就可以根据各种因素对其进行排序，包括透明度，距离，材质等。然后，您可以循环遍历队列并按正确的顺序进行所有绘制请求。

对于简单的情况，只需确保首先绘制不透明对象，然后按照一般的前后顺序绘制透明对象。

Direct3D 11深度模板/ alpha混合问题

1 个答案: