# init(color:texture:) Creates a color of emitted light in iOS. ``` init(color: NSColor = .black, texture: MaterialParameters.Texture? = nil) ``` ## Parameters `color` The color of the emitted light. Defaults to black. `texture` An optional UV-mapped image texture. ## Discussion This initializer creates an object from a color, an image texture, or from both. The `color` property defaults to black, which results in no light emissions. With custom materials, `color` and `texture` are available as inputs in your surface shader, but your surface shader must call `params.surface().set_emissive_color()`, otherwise RealityKit renders no light emission. The following Metal code demonstrates how to replicate the emissive behavior of [`PhysicallyBasedMaterial`](/documentation/RealityKit/PhysicallyBasedMaterial) in your surface shader code: ```swift // Retrieve the emissive color tint from the CustomMaterial. half3 emissiveColorTint = (half3)params.material_constants() .emissive_color_tint(); // Retrieve the primary texture coordinates. float2 uv = params.geometry().uv0(); // Flip the UV coordinate’s y-axis. You only need to do this // for models you load from USDZ or .reality files. uv.y = 1.0 - uv.y; auto tex = params.textures(); half3 color = (half3)tex.emissive_color() .sample(textureSampler, uv).rgb; // Multiply the tint and the sampled value from the texture, // and assign the result to the shader's emissive color // property. color *= emissiveColorTint; params.surface().set_emissive_color(color); ``` > Note: Unlike ``doc://com.apple.RealityKit/documentation/RealityKit/PhysicallyBasedMaterial``, ``doc://com.apple.RealityKit/documentation/RealityKit/CustomMaterial`` has no > ``doc://com.apple.RealityKit/documentation/RealityKit/PhysicallyBasedMaterial/emissiveIntensity`` value. If you need to pass > an emissive intensity value to your surface shader, use the > ``doc://com.apple.RealityKit/documentation/RealityKit/CustomMaterial/custom-swift.property`` property or another unused > attribute property. --- 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)