ios - SCNBox 在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。

这是我目前所得到的:

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第一个 Material ，还有一个属性用于一组 Material 。

具有多个元素和多种 Material 的对象将为每个元素选择递增的 Material (和包裹)。

例如4个元素和1个 Material

Element   1  2  3  4
Material  1  1  1  1

或 4 种元素和 2 种 Material

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

例如4种元素7种 Material

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

---

在盒子的情况下，这意味着您可以使用六种 Material 的阵列，在盒子的每一侧都有一种独特的 Material 。我在 the sample code for one of the chapters 中有一个这样的例子对于我的 Scene Kit 书(在 Objective-C 中):

// 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];