# fragment Use this entry point to change the color of a fragment after all other shading has been performed. ``` static let fragment: SCNShaderModifierEntryPoint ``` ## Discussion Shader modifiers for this entry point execute in the fragment processing stage. The fragment entry point defines the following structure: ```objc struct SCNShaderOutput { vec4 color; } _output; ``` Your shader modifier reads from this structure and writes a new color to the same structure to produce the final output color for each rendered fragment. This shader modifier inverts the output color: ```objc _output.color.rgb = vec3(1.0) - _output.color.rgb; ``` --- 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)