更新日期：2022年6月14日

RealityKit资料

目前RealityKit 2.0和RealityFoundation中有6种素材：

• SimpleMaterial
• UnlitMaterial
• OcclusionMaterial(阅读本文以了解如何设置SceneKit遮挡着色器)
• VideoMaterial(查看此帖子以了解如何设置)
• PhysicallyBasedMaterial
• CustomMaterial

要应用这些材质，请使用以下逻辑：

import Cocoa
import RealityKit

class ViewController: NSViewController {        
    @IBOutlet var arView: ARView!

    override func awakeFromNib() {
        let box = try! Experience.loadBox()

        var simpleMat = SimpleMaterial()
        simpleMat.color = .init(tint: .blue, texture: nil)
        simpleMat.metallic = .init(floatLiteral: 0.7)
        simpleMat.roughness = .init(floatLiteral: 0.2)

        var pbr = PhysicallyBasedMaterial()
        pbr.baseColor = .init(tint: .green, texture: nil) 

        let mesh: MeshResource = .generateBox(width: 0.5, 
                                             height: 0.5, 
                                              depth: 0.5, 
                                       cornerRadius: 0.02, 
                                         splitFaces: true)

        let boxComponent = ModelComponent(mesh: mesh,
                                     materials: [simpleMat, pbr])

        box.steelBox?.children[0].components.set(boxComponent)
        box.steelBox?.orientation = Transform(pitch: .pi/4, 
                                                yaw: .pi/4, 
                                               roll: 0).rotation
        arView.scene.anchors.append(box)
    }
}

阅读这篇文章，了解如何为RealityKit的着色器加载纹理。

如何创建类似于SceneKit着色器的RealityKit着色器

我们知道在SceneKit中有5种不同的着色器模型，所以我们可以使用RealityKit的SimpleMaterial、PhysicallyBasedMaterial和UnlitMaterial来生成我们已经习惯的所有这五个着色器。

让我们看看它是什么样子的：

SCNMaterial.LightingModel.blinn           – SimpleMaterial(color: . gray,
                                                        roughness: .float(0.5),
                                                       isMetallic: false)

SCNMaterial.LightingModel.lambert         – SimpleMaterial(color: . gray,
                                                        roughness: .float(1.0),
                                                       isMetallic: false)

SCNMaterial.LightingModel.phong           – SimpleMaterial(color: . gray,
                                                        roughness: .float(0.0),
                                                       isMetallic: false)

SCNMaterial.LightingModel.physicallyBased – PhysicallyBasedMaterial()

// all three shaders (`.constant`, `UnlitMaterial` and `VideoMaterial `) 
// don't depend on lighting
SCNMaterial.LightingModel.constant        – UnlitMaterial(color: .gray)
                                          – VideoMaterial(avPlayer: avPlayer)