Ios 使用Swift在ARKit中显示白色图像材质

我已经用SCNGeometryElement创建了节点，并应用图像内容材质显示白色，应用颜色内容工作正常。我有附加代码

func getsquareDrawnLineFrom(pos1: SCNVector3,
                            pos2: SCNVector3,
                            pos3: SCNVector3) -> SCNNode {

    let square = SquareplanlineFrom(vector1: pos1, vector2: pos2, vector3: pos3)
    let material = SCNMaterial()
    // material.diffuse.contents = UIColor.red
    material.diffuse.contents = UIImage(named: "grid")
    square.materials = [material]
    let square1 = SCNNode(geometry: square)
    square1.name = "tringle"
    return square1
}

// get line geometry between three vectors
func SquareplanlineFrom(vector1: SCNVector3,
                        vector2: SCNVector3, 
                        vector3: SCNVector3) -> SCNGeometry {

    let indices: [Int32] = [0, 1, 2]
    let source = SCNGeometrySource(vertices: [vector1, vector2, vector3])
    let element = SCNGeometryElement(indices: indices, primitiveType: .triangles)

    return SCNGeometry(sources: [source], elements: [element])
}

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要在自定义几何体上放置纹理，您需要实现两个更重要的类型属性：

SCNGeometrySource.Semantic.texcoord
SCNGeometrySource.Semantic.normal

它让纹理找出UV坐标和多边形法线方向，这样纹理就可以在多边形曲面上占据一定的空间

查看post和GitHub上的post，了解如何实现它

尽管如此，当您使用常规SceneKit基本体（如SCNSphere、SCNBox、SCNPlane等）或导入的三维模型（采用DAE、OBJ或USDZ文件格式）时，您不会考虑这些类型属性的实现，因为前面提到的几何体已经包含它们