init(color:texture:)

Declaration

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 in your surface shader code:

    // 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);