# MTLStages The segments of command execution within the Metal pass types. ``` struct MTLStages ``` ## Overview Metal associates each command with one or more stages within a pass. Use these stage identifiers to synchronize command execution within a pass by selecting which stages wait for other stages to complete. Metal 4 introduces the following unified command encoders that combine multiple stages into a single pass: - [`MTL4RenderCommandEncoder`](/documentation/Metal/MTL4RenderCommandEncoder) instances encode render passes that run vertex, fragment, object, mesh, and tile stages. - [`MTL4ComputeCommandEncoder`](/documentation/Metal/MTL4ComputeCommandEncoder) instances encode unified compute passes that run blit, dispatch, and acceleration structure stages. - [`MTL4MachineLearningCommandEncoder`](/documentation/Metal/MTL4MachineLearningCommandEncoder) instances encode passes that run machine learning stages. Metal 3 provides separate command encoders for different types of work: - [`MTLRenderCommandEncoder`](/documentation/Metal/MTLRenderCommandEncoder) instances encode render passes that run vertex, fragment, object, mesh, and tile stages. - [`MTLComputeCommandEncoder`](/documentation/Metal/MTLComputeCommandEncoder) instances encode compute passes that run dispatch stages. - [`MTLBlitCommandEncoder`](/documentation/Metal/MTLBlitCommandEncoder) instances encode blit passes that run blit stages, which initialize and copy data for resources, such as buffers and textures. - [`MTLAccelerationStructureCommandEncoder`](/documentation/Metal/MTLAccelerationStructureCommandEncoder) instances encode passes that run acceleration structure stages, such as for ray tracing. ## Topics ### Render pass stages [`MTLStageVertex`](/documentation/Metal/MTLStages/vertex) Represents all vertex shader stage work in a render pass. [`MTLStageFragment`](/documentation/Metal/MTLStages/fragment) Represents all fragment shader stage work in a render pass. [`MTLStageTile`](/documentation/Metal/MTLStages/tile) Represents all tile shading stage work in a render pass. [`MTLStageObject`](/documentation/Metal/MTLStages/object) Represents all object shader stage work in a render pass. [`MTLStageMesh`](/documentation/Metal/MTLStages/mesh) Represents all mesh shader stage work work in a render pass. ### Compute pass stages [`MTLStageDispatch`](/documentation/Metal/MTLStages/dispatch) Represents all compute dispatches in a compute pass. [`MTLStageBlit`](/documentation/Metal/MTLStages/blit) Represents all blit operations in a pass. [`MTLStageAccelerationStructure`](/documentation/Metal/MTLStages/accelerationStructure) Represents all acceleration structure operations. [`MTLStageMachineLearning`](/documentation/Metal/MTLStages/machineLearning) Represents all machine learning network dispatch operations. ### Resource pass stages [`MTLStageResourceState`](/documentation/Metal/MTLStages/resourceState) Represents all sparse and placement sparse resource mapping updates. ### Convenience values [`MTLStageAll`](/documentation/Metal/MTLStages/all) Convenience mask representing all stages of GPU work. ### Swift support [`init(rawValue:)`](/documentation/Metal/MTLStages/init(rawValue:)) ## Relationships ### Conforms To [`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable) [`OptionSet`](/documentation/Swift/OptionSet) [`SetAlgebra`](/documentation/Swift/SetAlgebra) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`RawRepresentable`](/documentation/Swift/RawRepresentable) [`Equatable`](/documentation/Swift/Equatable) [`Sendable`](/documentation/Swift/Sendable) [`ExpressibleByArrayLiteral`](/documentation/Swift/ExpressibleByArrayLiteral) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)