如果箭头始终面向相机(如您附加的图像),则可以使用SCNPlane,并将箭头图像用作纹理。
如果它不会始终面向相机,您可能需要给它一些厚度。如果正确操作,则我不认为其他答案比您尝试的方法更好。
Obj C代码(编辑:下面添加了Swift版本)
int vertcount = 48;
float verts[] = { -14.923, 11.824, 25.000, -64.923, 0.000, 0.000, -14.923, -11.824, 25.000, 46.077, -5.812, 16.800, 46.077, -5.812, -16.800, 46.077, 5.812, -16.800, 46.077, 5.812, 16.800, -14.923, -11.824, -25.000, -14.923, 11.824, -25.000, -14.923, 4.974, -9.969, -14.923, 4.974, 9.969, -14.923, -4.974, 9.969, -14.923, -4.974, -9.969 };
int facecount = 13;
int faces[] = { 3, 4, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 0, 1, 2, 3, 4, 5, 6, 7, 1, 8, 8, 1, 0, 2, 1, 7, 9, 8, 0, 10, 10, 0, 2, 11, 11, 2, 7, 12, 12, 7, 8, 9, 9, 5, 4, 12, 10, 6, 5, 9, 11, 3, 6, 10, 12, 4, 3, 11};
NSData *vertsData = [NSData dataWithBytes:&verts length:sizeof(verts)];
SCNGeometrySource *vertexSource = [SCNGeometrySource geometrySourceWithData: vertsData
semantic:SCNGeometrySourceSemanticVertex
vectorCount:vertcount
floatComponents:YES
componentsPerVector:3
bytesPerComponent:sizeof(float)
dataOffset:0
dataStride:sizeof(float)*3];
int polyIndexCount = 61;
NSData *indexPolyData = [NSData dataWithBytes:faces length:sizeof(int) * polyIndexCount];
SCNGeometryElement *element1 = [SCNGeometryElement geometryElementWithData:indexPolyData
primitiveType:SCNGeometryPrimitiveTypePolygon
primitiveCount:facecount
bytesPerIndex:sizeof(int)];
SCNGeometry *geometry1 = [SCNGeometry geometryWithSources:@[ vertexSource ] elements:@[ element1]];
//Assign the SCNGeometry to a SCNNode, for example:
//SCNNode *aNode = [[SCNNode alloc] init];
//aNode.geometry = geometry1;
请注意它使用多边形原始类型。
通过将浮点数四舍五入,可以清理顶点列表。
这将创建以下3D箭头(不可见顶点和边):
编辑:SWIFT版本:
let vertcount = 48;
let verts: [Float] = [ -1.4923, 1.1824, 2.5000, -6.4923, 0.000, 0.000, -1.4923, -1.1824, 2.5000, 4.6077, -0.5812, 1.6800, 4.6077, -0.5812, -1.6800, 4.6077, 0.5812, -1.6800, 4.6077, 0.5812, 1.6800, -1.4923, -1.1824, -2.5000, -1.4923, 1.1824, -2.5000, -1.4923, 0.4974, -0.9969, -1.4923, 0.4974, 0.9969, -1.4923, -0.4974, 0.9969, -1.4923, -0.4974, -0.9969 ];
let facecount = 13;
let faces: [CInt] = [ 3, 4, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 0, 1, 2, 3, 4, 5, 6, 7, 1, 8, 8, 1, 0, 2, 1, 7, 9, 8, 0, 10, 10, 0, 2, 11, 11, 2, 7, 12, 12, 7, 8, 9, 9, 5, 4, 12, 10, 6, 5, 9, 11, 3, 6, 10, 12, 4, 3, 11 ];
let vertsData = NSData(
bytes: verts,
length: MemoryLayout<Float>.size * vertcount
)
let vertexSource = SCNGeometrySource(data: vertsData as Data,
semantic: .vertex,
vectorCount: vertcount,
usesFloatComponents: true,
componentsPerVector: 3,
bytesPerComponent: MemoryLayout<Float>.size,
dataOffset: 0,
dataStride: MemoryLayout<Float>.size * 3)
let polyIndexCount = 61;
let indexPolyData = NSData( bytes: faces, length: MemoryLayout<CInt>.size * polyIndexCount )
let element1 = SCNGeometryElement(data: indexPolyData as Data,
primitiveType: .polygon,
primitiveCount: facecount,
bytesPerIndex: MemoryLayout<CInt>.size)
let geometry1 = SCNGeometry(sources: [vertexSource], elements: [element1])
let material1 = geometry1.firstMaterial!
material1.diffuse.contents = UIColor(red: 0.14, green: 0.82, blue: 0.95, alpha: 1.0)
material1.lightingModel = .lambert
material1.transparency = 1.00
material1.transparencyMode = .dualLayer
material1.fresnelExponent = 1.00
material1.reflective.contents = UIColor(white:0.00, alpha:1.0)
material1.specular.contents = UIColor(white:0.00, alpha:1.0)
material1.shininess = 1.00
//Assign the SCNGeometry to a SCNNode, for example:
let aNode = SCNNode()
aNode.geometry = geometry1
//aNode.scale = SCNVector3(0.1, 0.1, 0.1)
scene.rootNode.addChildNode(aNode)
为了确保其有效性,测试了上面的Swift代码:
如果您需要使其更小,请取消注释.scale行并尝试不同的值以查看所需大小。例如,如果您最终希望其比例为0.06,则建议通过将其中的值乘以0.06来重新生成顶点列表,然后删除比例行。
对于这样的形状,最好创建一个平面的 UIBezierPath
用于箭头,然后通过将路径挤出来获得三维几何体来创建 SCNShape
。