SCNBox 每张脸上都有不同的颜色或纹理

Question

我是 iOS 开发的新手，我被难住了。我正在尝试使用 SceneKit 渲染一个立方体，每个面都有不同的颜色。

这是我目前得到的：

func sceneSetup() {
    // 1
    let scene = SCNScene()

    // 2
    let BoxGeometry = SCNBox(width: 0.9, height: 0.9, length: 0.9, chamferRadius: 0.0)

    BoxGeometry.firstMaterial?.diffuse.contents = UIColor.redColor()
    let cube = SCNNode(geometry: BoxGeometry)
    cube.position = SCNVector3(x: 0, y: 0, z: -1)
    scene.rootNode.addChildNode(cube)

    // 3
    sceneView.scene = scene
    sceneView.autoenablesDefaultLighting = true
    sceneView.allowsCameraControl = true

但我希望每张脸都有不同的颜色。我该怎么做？

Answer 1

盒子由六个不同的元素组成（每边一个）。您可能还注意到，几何对象有一个属性用于 first 材质，但也有一个属性用于材质数组。

具有多个元素和多种材质的对象将为每个元素选择材质（和包裹）增量。

例如 4 个元素和 1 个材质

Element   1  2  3  4
Material  1  1  1  1

或 4 个元素和 2 个材料

Element   1  2  3  4
Material  1  2  1  2  // note that they are repeating 

例如 4 个元素和 7 个材质

Element   1  2  3  4
Material  1  2  3  4  // (5, 6, 7) is unused

---

就盒子而言，这意味着您可以使用包含六种材质的数组来在盒子的每一侧拥有一种独特的材质。我在 the sample code for one of the chapters 我的 Scene Kit 书（在 Objective-C 中）有一个这样的例子：

// Each side of the box has its own color
// --------------------------------------
// All have the same diffuse and ambient colors to show the
// effect of the ambient light, even with these materials.

SCNMaterial *greenMaterial              = [SCNMaterial material];
greenMaterial.diffuse.contents          = [NSColor greenColor];
greenMaterial.locksAmbientWithDiffuse   = YES;

SCNMaterial *redMaterial                = [SCNMaterial material];
redMaterial.diffuse.contents            = [NSColor redColor];
redMaterial.locksAmbientWithDiffuse     = YES;

SCNMaterial *blueMaterial               = [SCNMaterial material];
blueMaterial.diffuse.contents           = [NSColor blueColor];
blueMaterial.locksAmbientWithDiffuse    = YES;

SCNMaterial *yellowMaterial             = [SCNMaterial material];
yellowMaterial.diffuse.contents         = [NSColor yellowColor];
yellowMaterial.locksAmbientWithDiffuse  = YES;

SCNMaterial *purpleMaterial             = [SCNMaterial material];
purpleMaterial.diffuse.contents         = [NSColor purpleColor];
purpleMaterial.locksAmbientWithDiffuse  = YES;

SCNMaterial *magentaMaterial            = [SCNMaterial material];
magentaMaterial.diffuse.contents        = [NSColor magentaColor];
magentaMaterial.locksAmbientWithDiffuse = YES;


box.materials =  @[greenMaterial,  redMaterial,    blueMaterial,
                   yellowMaterial, purpleMaterial, magentaMaterial];

Answer 2

这是 Swift 4 的答案。

    let colors = [UIColor.green, // front
                  UIColor.red, // right
                  UIColor.blue, // back
                  UIColor.yellow, // left
                  UIColor.purple, // top
                  UIColor.gray] // bottom

    let sideMaterials = colors.map { color -> SCNMaterial in
        let material = SCNMaterial()
        material.diffuse.contents = color
        material.locksAmbientWithDiffuse = true
        return material
    }

    materials = sideMaterials

要改变前面的材料，只需抓住材料并改变它的内容

let frontMaterial = materials[0]
frontMaterial.diffuse.contents = UIColor.white

Answer 3

感谢您的快速帮助。我使用了您提出的代码但无法使用 NSColor 所以我尝试了 uicolor 但我得到的只是一个黑色立方体所以我尝试了这个并且我得到了它的工作

    let BoxGeometry = SCNBox(width: 0.95, height: 0.95, length: 0.95, chamferRadius: 0.0)

    let greenMaterial = SCNMaterial()
    greenMaterial.diffuse.contents = UIImage(named: "g")
    greenMaterial.locksAmbientWithDiffuse = true;

    let redMaterial = SCNMaterial()
    redMaterial.diffuse.contents = UIImage(named: "r")
    redMaterial.locksAmbientWithDiffuse = true;


    let blueMaterial  = SCNMaterial()
    blueMaterial.diffuse.contents = UIImage(named: "b")
    blueMaterial.locksAmbientWithDiffuse = true;


    let yellowMaterial = SCNMaterial()
    yellowMaterial.diffuse.contents = UIImage(named: "y")
    yellowMaterial.locksAmbientWithDiffuse = true;


    let purpleMaterial = SCNMaterial()
    purpleMaterial.diffuse.contents = UIImage(named: "p")
    purpleMaterial.locksAmbientWithDiffuse = true;


    let WhiteMaterial = SCNMaterial()
    WhiteMaterial.diffuse.contents = UIImage(named: "w")
    WhiteMaterial.locksAmbientWithDiffuse   = true;


    BoxGeometry.materials =  [greenMaterial,  redMaterial,    blueMaterial,
    yellowMaterial, purpleMaterial, WhiteMaterial];

g 是一个绿色的 jpeg 等等，现在它已经开始工作了。