MSAA Render To Single Sampled/Multisampled Render To Single Sampled

The msaa-render-to-single-sampled feature allows a render pass to include single-sampled attachments while rendering is done with a specified number of samples. When this feature is used, the client doesn't need to explicitly allocate any multi-sammpled color textures. We denote this kind of render passes as “implicit multi-sampled” render passes.

Additional functionalities:

  • Adds wgpu::DawnRenderPassColorAttachmentRenderToSingleSampled as chained struct for wgpu::RenderPassColorAtttachment to specify number of samples to be rendered for the respective single-sampled attachment.
  • Adds wgpu::DawnMultisampleStateRenderToSingleSampled as chained struct for wgpu::RenderPipelineDescriptor::MultisampleState to indicate that the render pipeline is going to be used in a “implicit multi-sampled” render pass.

Example Usage:

// Create texture with TextureBinding usage.
wgpu::TextureDescriptor desc = ...;
desc.usage = wgpu::TextureUsage::RenderAttachment | wgpu::TextureUsage::TextureBinding;

auto texture = device.CreateTexture(&desc);

// Create a render pipeline to be used in a "implicit multi-sampled" render pass.
wgpu::DawnMultisampleStateRenderToSingleSampled pipelineMSAARenderToSingleSampledDesc;
pipelineMSAARenderToSingleSampledDesc.enabled = true;

wgpu::RenderPipelineDescriptor pipelineDesc = ...;
pipelineDesc.multisample.count = 4;
pipelineDesc.multisample.nextInChain = &pipelineMSAARenderToSingleSampledDesc;

auto pipeline = device.CreateRenderPipeline(&pipelineDesc);

// Create a render pass with "implicit multi-sampled" enabled.
wgpu::DawnRenderPassColorAttachmentRenderToSingleSampled colorAttachmentRenderToSingleSampledDesc;
colorAttachmentRenderToSingleSampledDesc.implicitSampleCount = 4;

wgpu::RenderPassDescriptor renderPassDesc = ...;
renderPassDesc.colorAttachments[0].view = texture.CreateView();
  = &colorAttachmentRenderToSingleSampledDesc;

auto renderPassEncoder = encoder.BeginRenderPass(&renderPassDesc);



  • If a texture needs to be used as an attachment in a “implicit multi-sampled” render pass, it must have wgpu::TextureUsage::TextureBinding usage.
  • If wgpu::DawnMultisampleStateRenderToSingleSampled chained struct is not included in a wgpu::RenderPipelineDescriptor::MultisampleState or if it is included but enabled boolean flag is false, then the result render pipeline cannot be used in a “implicit multi-sampled” render pass.
    • Similarly, a render pipeline created with wgpu::DawnMultisampleStateRenderToSingleSampled‘s enabled flag = true won’t be able to be used in normal render passes.
  • If a texture is attached to a “implicit multi-sampled” render pass. It must be single-sampled. It mustn‘t be assigned to the resolveTarget field of the the render pass’ color attachment.
  • Depth stencil textures can be attached to a “implicit multi-sampled” render pass. But its sample count must match the number specified in one color attachment's wgpu::DawnRenderPassColorAttachmentRenderToSingleSampled's implicitSampleCount field.
  • Currently only one color attachment is supported, this could be changed in future.
  • The texture is not supported if it is not resolvable by WebGPU standard. This means this feature currently doesn't work with integer textures.