# MTLRenderPipelineColorAttachmentDescriptor A color render target that specifies the color configuration and color operations for a render pipeline. ``` class MTLRenderPipelineColorAttachmentDescriptor ``` ## Overview An [`MTLRenderPipelineColorAttachmentDescriptor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor) instance defines the configuration of a color attachment associated with a rendering pipeline. The [`pixelFormat`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/pixelFormat) property needs to be specified for the rendering pipeline state at the color attachment. Blend operations determine how a source fragment is combined with a destination value in a color attachment to determine the pixel value to be written. The following properties define whether and how blending is performed: - The [`isBlendingEnabled`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/isBlendingEnabled) property enables blending. The default value is . - The [`writeMask`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/writeMask) property identifies which color channels are blended. The default value is [`all`](/documentation/Metal/MTLColorWriteMask/all), which allows all color channels to be blended. - The [`rgbBlendOperation`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/rgbBlendOperation) and [`alphaBlendOperation`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/alphaBlendOperation) properties assign the blend operations for RGB and alpha pixel data. The default value for both properties is [`MTLBlendOperation.add`](/documentation/Metal/MTLBlendOperation/add). - The [`sourceRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceRGBBlendFactor), [`sourceAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceAlphaBlendFactor), [`destinationRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationRGBBlendFactor), and [`destinationAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationAlphaBlendFactor) properties assign the source and destination blend factors. The default value for [`sourceRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceRGBBlendFactor) and [`sourceAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceAlphaBlendFactor) is [`MTLBlendFactor.one`](/documentation/Metal/MTLBlendFactor/one). The default value for [`destinationRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationRGBBlendFactor) and [`destinationAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationAlphaBlendFactor) is [`MTLBlendFactor.zero`](/documentation/Metal/MTLBlendFactor/zero). ## Topics ### Configuring render pipeline states [`pixelFormat`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/pixelFormat) The pixel format of the color attachment’s texture. [`writeMask`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/writeMask) A bitmask that restricts which color channels are written into the texture. [`MTLColorWriteMask`](/documentation/Metal/MTLColorWriteMask) Values used to specify a mask to permit or restrict writing to color channels of a color value. ### Controlling blend operations [`isBlendingEnabled`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/isBlendingEnabled) A Boolean value that determines whether blending is enabled. [`alphaBlendOperation`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/alphaBlendOperation) The blend operation assigned for the alpha data. [`rgbBlendOperation`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/rgbBlendOperation) The blend operation assigned for the RGB data. [`MTLBlendOperation`](/documentation/Metal/MTLBlendOperation) For every pixel, `MTLBlendOperation` determines how to combine and weight the source fragment values with the destination values. Some blend operations multiply the source values by a source blend factor (SBF), multiply the destination values by a destination blend factor (DBF), and then combine the results using addition or subtraction. Other blend operations use either a minimum or maximum function to determine the result. ### Configuring blend factors [`destinationAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationAlphaBlendFactor) The destination blend factor (DBF) used by the alpha blend operation. [`destinationRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/destinationRGBBlendFactor) The destination blend factor (DBF) used by the RGB blend operation. [`sourceAlphaBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceAlphaBlendFactor) The source blend factor (SBF) used by the alpha blend operation. [`sourceRGBBlendFactor`](/documentation/Metal/MTLRenderPipelineColorAttachmentDescriptor/sourceRGBBlendFactor) The source blend factor (SBF) used by the RGB blend operation. [`MTLBlendFactor`](/documentation/Metal/MTLBlendFactor) The source and destination blend factors are often needed to complete specification of a blend operation. In most cases, the blend factor for both RGB values (*F(rgb)*) and alpha values (*F(a)*) are similar to one another, but in some cases, such as `MTLBlendFactorSourceAlphaSaturated`, the blend factor is slightly different. Four blend factors (`MTLBlendFactorBlendColor`, `MTLBlendFactorOneMinusBlendColor`, `MTLBlendFactorBlendAlpha`, and `MTLBlendFactorOneMinusBlendAlpha`) refer to a constant blend color value that is set by the [`setBlendColor(red:green:blue:alpha:)`](/documentation/Metal/MTLRenderCommandEncoder/setBlendColor(red:green:blue:alpha:)) method of `MTLRenderCommandEncoder`. --- Copyright © 2026 Apple Inc. 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