# setViewport(_:) Configures the render pipeline with a viewport that applies a transformation and a clipping rectangle. ``` func setViewport(_ viewport: MTLViewport) ``` ## Parameters `viewport` An [`MTLViewport`](/documentation/Metal/MTLViewport) instance the command applies to the render pipeline for transformations and clipping. ## Discussion The render pipeline linearly maps vertex positions from normalized device coordinates to viewport coordinates by applying a viewport during the rasterization stage. It applies the transform first and then rasterizes the primitive while clipping any fragments outside the scissor rectangle (see [`setScissorRect(_:)`](/documentation/Metal/MTLRenderCommandEncoder/setScissorRect(_:))) or the render target’s extents. The viewport’s [`originX`](/documentation/Metal/MTLViewport/originX) and [`originY`](/documentation/Metal/MTLViewport/originY) properties, which default to `0.0`, represent the number of pixels from the top-left corner of the render target. Positive [`originX`](/documentation/Metal/MTLViewport/originX) values go to the right and positive [`originY`](/documentation/Metal/MTLViewport/originY) values go downward. The default values for its [`width`](/documentation/Metal/MTLViewport/width) and [`height`](/documentation/Metal/MTLViewport/height) properties are the render target’s width and height, respectively. The default values for its [`znear`](/documentation/Metal/MTLViewport/znear) and [`zfar`](/documentation/Metal/MTLViewport/zfar) properties are `0.0` and `1.0`, respectively, which you can flip. > Note: > You can change the render pass’s viewport configuration by calling this method again, or by calling the ``doc://com.apple.metal/documentation/Metal/MTLRenderCommandEncoder/setViewports(_:)`` method. --- 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)