Adding a material to a ModelEntity programmatically

问题

The docs for RealityKit include the structs: OcclusionMaterial, SimpleMaterial, and UnlitMaterial for adding materials to a ModelEntity.

Alternatively you can load in a model with a material attached to it.

I want to add a custom material/texture to a ModelEntity programmatically. How can I achieve this on the fly without adding the material to a model in Reality Composer or some other 3D software?

回答1:

Updated : 21st October 2019.

As you said, there are 3 types of materials in RealityKit 1.0 at the moment: `

• SimpleMaterial
• UnlitMaterial
• OcclusionMaterial

So you can use the following code with a SimpleMaterial() class:

@IBOutlet var arView: ARView!

let sceneObjects = try! Experience.loadMy3dObjects()

var simpleMaterial = SimpleMaterial()

simpleMaterial.baseColor = try! MaterialColorParameter.texture(
                                          TextureResource.load(named: "image.jpg"))

simpleMaterial.metallic = MaterialScalarParameter(floatLiteral: 0.9)
simpleMaterial.roughness = MaterialScalarParameter(floatLiteral: 0.1)
simpleMaterial.tintColor = UIColor.yellow

/*

simpleMaterial.baseColor = MaterialColorParameter.color(UIColor(red: 0.7,
                                                              green: 0.5,
                                                               blue: 0.2,
                                                              alpha: 1.0))
*/

At the moment there are 4 methods in RealityKit to create simple 3D primitives:

• generateBox()
• generateSphere()
• generatePlane()
• generateText()

So let's use one of them:

let mesh: MeshResource = .generateBox(size: 2.5)

let component = ModelComponent(mesh: mesh, 
                          materials: [simpleMaterial])

sceneObjects.components.set(component)
arView.scene.anchors.append(sceneObjects)

print("\(component.mesh.bounds)")
print("\(component.materials.count)")

来源：https://stackoverflow.com/questions/56828648/adding-a-material-to-a-modelentity-programmatically