24

I'm new to iOS development and I've got myself stumped. I am trying to render a cube using SceneKit that has a different colour for each face.

This is what I've got so far:

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

But I'd like each face to have a different colour. How do I do that?

4

3 回答 3

25

盒子由六个不同的元素组成（每边一个）。您可能还注意到，几何对象具有第一种材料的一个属性，以及一组材料的属性。

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）的增量。

例如 4 个元素和 1 个材料

Element   1  2  3  4
Material  1  1  1  1

或 4 种元素和 2 种材料

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

例如 4 种元素和 7 种材料

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一组六种材料在盒子的每一侧都有一个独特的材料。我的Scene Kit 书（在 Objective-C 中）的其中一章的示例代码中有一个示例：

// 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];
于 2014-12-16T16:56:53.253 回答
16

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

要更改前面的材料，只需抓取材料并更改其内容

let frontMaterial = materials[0]
frontMaterial.diffuse.contents = UIColor.white
于 2017-08-01T21:15:01.653 回答
4

thai you for the fast help. i used the code you posed but was unable to use NSColor so i tried uicolor but all i was getting was a black cube so i tried this and i got it working 

    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 is a jpeg of a green and so on and that has got it working now.

于 2014-12-17T05:39:43.503 回答