使用SCNGeometryPrimitiveType多边形崩溃/错误创建自定义SCNGeometry多边形平面
我正在尝试创建具有自定义形状的平面形式的自定义SCNGeometry，可以将其放置在ARKit会话中。我正在以下方法中使用选项SCNGeometryPrimitiveTypePolygon，该方法似乎正常工作：
extension SCNGeometry {
static func polygonPlane(vertices: [SCNVector3]) -> SCNGeometry {
var indices: [Int32] = [Int32(vertices.count)]
var index: Int32 = 0
for _ in vertices {
indices.append(index)
index += 1
}
let vertexSource = SCNGeometrySource(vertices: vertices)
let indexData = Data(bytes: indices, count: indices.count * MemoryLayout<Int32>.size)
let element = SCNGeometryElement(data: indexData, primitiveType: .polygon, primitiveCount: 1, bytesPerIndex: MemoryLayout<Int32>.size)
let geometry = SCNGeometry(sources: [vertexSource], elements: [element])
let material = SCNMaterial()
material.diffuse.contents = UIColor.blue
material.isDoubleSided = true
geometry.firstMaterial = material
return geometry
}
创建此几何后，我将其分配给SCNNode:s .geometry属性，并照常将其添加到我的AR场景中：
let geometry = SCNGeometry.polygonPlane(vertices: verticesArray)
let node = SCNNode(geometry: geometry)
sceneView.scene.rootNode.addChildNode(node)
这对于某些类型的平面形状效果很好。但是，我经常会崩溃，主要是在使用复杂形状或许多顶点绘制平面形状时。我进行了尝试，似乎可以按预期创建几何体而没有任何错误，但是当将节点添加到场景并即将渲染时，就会发生错误。这是打印错误：
-[MTLDebugDevice validateNewBufferArgs:options:]:467: failed assertion `Cannot create buffer of zero length.'
调试导航器中显示的内容：
最后是堆栈跟踪：
* thread #17, name = 'com.apple.scenekit.scnview-renderer', queue = 'com.apple.scenekit.renderingQueue.ARSCNView0x11be03ed0', stop reason = signal SIGABRT
* frame #0: 0x0000000219cad0cc libsystem_kernel.dylib`__pthread_kill + 8
frame #1: 0x0000000219d23a88 libsystem_pthread.dylib`pthread_kill + 300
frame #2: 0x0000000219c0614c libsystem_c.dylib`abort + 144
frame #3: 0x0000000219bd3274 libsystem_c.dylib`__assert_rtn + 224
frame #4: 0x000000021c28e23c Metal`MTLReportFailure + 528
frame #5: 0x000000023f984108 MetalTools`-[MTLDebugDevice validateNewBufferArgs:options:] + 172
frame #6: 0x000000023f98430c MetalTools`-[MTLDebugDevice newBufferWithBytes:length:options:] + 128
frame #7: 0x000000022e323b48 SceneKit`-[SCNMTLResourceManager _bufferForData:bytesPerIndex:] + 404
frame #8: 0x000000022e323f14 SceneKit`-[SCNMTLResourceManager renderResourceForMeshElement:] + 416
frame #9: 0x000000022e3243c0 SceneKit`-[SCNMTLResourceManager renderResourceForMesh:dataKind:] + 692
frame #10: 0x000000022e364980 SceneKit`_execute(SCNMTLRenderContext*, DrawCommand) + 916
frame #11: 0x000000022e3644a0 SceneKit`-[SCNMTLRenderContext drawRenderElement:withPass:] + 608
frame #12: 0x000000022e3630d4 SceneKit`-[SCNMTLRenderContext processRendererElements:count:engineIterationContext:] + 1044
frame #13: 0x000000022e4afc54 SceneKit`C3D::DrawNodesPass::_renderEye(long) + 472
frame #14: 0x000000022e4afa00 SceneKit`C3D::DrawNodesPass::execute(C3D::RenderArgs const&) + 260
frame #15: 0x000000022e54a1b4 SceneKit`C3D::MainPass::execute(C3D::RenderArgs const&) + 176
frame #16: 0x000000022e318904 SceneKit`C3D::__renderSlice(C3D::RenderGraph*, C3D::RenderPass*, unsigned short&, C3D::RenderGraph::GraphNode const&, C3D::RenderGraph::Stage*&, C3D::RenderArgs) + 1156
frame #17: 0x000000022e319cd0 SceneKit`C3D::RenderGraph::execute() + 3896
frame #18: 0x000000022e42fd8c SceneKit`-[SCNRenderer _renderSceneWithEngineContext:sceneTime:] + 2364
frame #19: 0x000000022e42ff44 SceneKit`-[SCNRenderer _drawSceneWithNewRenderer:] + 312
frame #20: 0x000000022e43056c SceneKit`-[SCNRenderer _drawScene:] + 72
frame #21: 0x000000022e4309bc SceneKit`-[SCNRenderer _drawAtTime:] + 760
frame #22: 0x000000022e4dfecc SceneKit`-[SCNView _drawAtTime:] + 492
frame #23: 0x000000022e37c15c SceneKit`__69-[NSObject(SCN_DisplayLinkExtensions) SCN_setupDisplayLinkWithQueue:]_block_invoke + 60
frame #24: 0x000000022e4a1c50 SceneKit`__36-[SCNDisplayLink _callbackWithTime:]_block_invoke + 88
frame #25: 0x0000000104d74778 libdispatch.dylib`_dispatch_client_callout + 20
frame #26: 0x0000000104d82fc0 libdispatch.dylib`_dispatch_lane_barrier_sync_invoke_and_complete + 160
frame #27: 0x000000022e4a1bb8 SceneKit`-[SCNDisplayLink _callbackWithTime:] + 268
frame #28: 0x0000000104e082d4 GPUToolsCore`-[DYDisplayLinkInterposer forwardDisplayLinkCallback:] + 204
frame #29: 0x000000021e53aea8 QuartzCore`CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 632
frame #30: 0x000000021e608858 QuartzCore`display_timer_callback(__CFMachPort*, void*, long, void*) + 276
frame #31: 0x000000021a083058 CoreFoundation`__CFMachPortPerform + 192
frame #32: 0x000000021a0aaaf0 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 60
frame #33: 0x000000021a0aa1e8 CoreFoundation`__CFRunLoopDoSource1 + 444
frame #34: 0x000000021a0a4d80 CoreFoundation`__CFRunLoopRun + 2060
frame #35: 0x000000021a0a4254 CoreFoundation`CFRunLoopRunSpecific + 452
frame #36: 0x000000021aa8404c Foundation`-[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 304
frame #37: 0x000000022e37c518 SceneKit`__49-[SCNView(SCNDisplayLink) _initializeDisplayLink]_block_invoke + 444
frame #38: 0x000000022e37c684 SceneKit`__SCNRenderThread_start__ + 104
frame #39: 0x0000000219d22908 libsystem_pthread.dylib`_pthread_body + 132
frame #40: 0x0000000219d22864 libsystem_pthread.dylib`_pthread_start + 48
frame #41: 0x0000000219d2adcc libsystem_pthread.dylib`thread_start + 4
warning: failed to set breakpoint site at 0x21931425c for breakpoint -4.1: error sending the breakpoint request
warning: failed to set breakpoint site at 0x219314530 for breakpoint -4.2: error sending the breakpoint request
warning: failed to set breakpoint site at 0x2193141b4 for breakpoint -4.3: error sending the breakpoint request
warning: failed to set breakpoint site at 0x21931fcc4 for breakpoint -5.1: error sending the breakpoint request
我没有快速调试的经验，但在我看来，问题出在某些金属框架代码中的第4-6帧某处：
frame #4: 0x000000021c28e23c Metal`MTLReportFailure + 528
frame #5: 0x000000023f984108 MetalTools`-[MTLDebugDevice validateNewBufferArgs:options:] + 172
frame #6: 0x000000023f98430c MetalTools`-[MTLDebugDevice newBufferWithBytes:length:options:] + 128
感谢您的帮助/建议！
----编辑1 ----
这是一个不会产生此错误的数组：
vertices = [ //Array that should work
SCNVector3(x: -0.06110339, y: -0.00659544, z: -0.18046863),
SCNVector3(x: -0.06406027, y: -0.008907169, z: -0.18053372),
SCNVector3(x: -0.06406027, y: -0.008907169, z: -0.18053372),
SCNVector3(x: -0.06701318, y: -0.013257578, z: -0.18059872),
SCNVector3(x: -0.069427274, y: -0.017816536, z: -0.18065183),
SCNVector3(x: -0.07077661, y: -0.02299612, z: -0.18068156),
SCNVector3(x: -0.07138735, y: -0.029295363, z: -0.18069498),
SCNVector3(x: -0.07159121, y: -0.035330035, z: -0.1806995),
SCNVector3(x: -0.06850778, y: -0.039139934, z: -0.1806316),
SCNVector3(x: -0.059540674, y: -0.039537176, z: -0.18043421),
SCNVector3(x: -0.04808737, y: -0.035914123, z: -0.1801821),
SCNVector3(x: -0.045074403, y: -0.035180397, z: -0.1801158)
]
这是使用此数组时来自我的应用程序的两个屏幕截图。如您所见，由于所有顶点位置都是从该平面上的点击测试中选取的，因此多边形位于平面内。不要介意剪裁的颜色，因为它是Z形拼合的，并且可以通过偏移平面轻松地进行固定：
这是一个生成此错误的顶点数组的示例：
vertices = [ //Array that should not work
SCNVector3(x: 0.08866002, y: -0.007735528, z: -0.09841499),
SCNVector3(x: 0.08873053, y: -0.014926873, z: -0.09837532),
SCNVector3(x: 0.08873053, y: -0.014926873, z: -0.09837532),
SCNVector3(x: 0.08846086, y: -0.024348512, z: -0.09852711),
SCNVector3(x: 0.08749959, y: -0.034751557, z: -0.09906833),
SCNVector3(x: 0.08527064, y: -0.043312013, z: -0.10032329),
SCNVector3(x: 0.08125973, y: -0.049623042, z: -0.10258152),
SCNVector3(x: 0.07674095, y: -0.054563493, z: -0.10512567),
SCNVector3(x: 0.07041831, y: -0.057908192, z: -0.10868551),
SCNVector3(x: 0.06373097, y: -0.058204524, z: -0.112450644),
SCNVector3(x: 0.058445737, y: -0.057790123, z: -0.115426354),
SCNVector3(x: 0.054485526, y: -0.05334358, z: -0.11765605),
SCNVector3(x: 0.052902386, y: -0.04610482, z: -0.1185474),
SCNVector3(x: 0.053534307, y: -0.036374755, z: -0.118191615),
SCNVector3(x: 0.055890974, y: -0.027881026, z: -0.11686475),
SCNVector3(x: 0.059101492, y: -0.022751786, z: -0.115057185),
SCNVector3(x: 0.062345386, y: -0.02150976, z: -0.113230795),
SCNVector3(x: 0.06506948, y: -0.022176817, z: -0.11169703)
]
这是使用该数组时的屏幕截图。蓝色平面是该方法有效的实例，但如果仔细观察，则会出现一条红线。这条红线紧跟着上面的不良数组的顶点，当使用相应几何图形的多边形平面添加到场景中时，这会立即使应用程序崩溃：
----编辑2 ----
下面是@ARGeo的macOS解决方案的代码，但略作修改以适合我的iOS应用并使用任意数量的顶点。该代码适用于先前失败的顶点数组，但是在使用另一个顶点数组时再次失败。就像@ARGeo所建议的那样，如果在扩展程序中使用MemoryLayout<Int32>.size会导致问题，我确保将此方法放在实际的类中，而不是在扩展程序中。
private func createPolygon(){
func model(vertices: [SCNVector3]) -> SCNNode {
let polyDraw = draw(vertices: vertices)
let material = SCNMaterial()
material.diffuse.contents = UIColor.green
material.isDoubleSided = true
material.diffuse.contentsTransform = .init(m11: 0.1, m12: 0, m13: 0, m14: 0,
m21: 0, m22: 0.1, m23: 0, m24: 0,
m31: 0, m32: 0, m33: 0, m34: 0,
m41: 0, m42: 0, m43: 0, m44: 1)
material.diffuse.wrapS = .repeat
material.diffuse.wrapT = .repeat
polyDraw.materials = [material]
let node = SCNNode(geometry: polyDraw)
//node.scale = SCNVector3(x: 200, y: 200, z: 200)
sceneView.scene.rootNode.addChildNode(node)
return node
}
func draw(vertices: [SCNVector3]) -> SCNGeometry {
let normalsPerFace = 1
var indices: [Int32] = []
indices.append(Int32(vertices.count))
//Add the rest of the indices 0 to vertices.count-1
for i in 0 ... vertices.count-1 {
indices.append(Int32(i))
}
let source = SCNGeometrySource(vertices: vertices)
let vec = vertices.map { [SCNVector3](repeating: $0,
count: normalsPerFace) }.flatMap{ $0 }
let normals: [SCNVector3] = vec
let normalSource = SCNGeometrySource(normals: normals)
var cgps: [CGPoint] = []
vertices.forEach { (vertex) in
cgps.append(CGPoint(x: CGFloat(vertex.x), y: CGFloat(vertex.y)))
}
let textcoord = SCNGeometrySource(textureCoordinates: cgps)
let data = Data(bytes: indices,
count: indices.count * MemoryLayout<Int32>.size)
let element = SCNGeometryElement(data: data,
primitiveType: .polygon,
primitiveCount: 1,
bytesPerIndex: MemoryLayout<Int32>.size)
return SCNGeometry(sources: [source, normalSource, textcoord], elements: [element])
}
//Previous fail, now success with ARGeo's code
let vertices = [SCNVector3(x: 0.08866002, y: -0.00773552, z: -0.09841499),
SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
SCNVector3(x: 0.08846086, y: -0.02434851, z: -0.09852711),
SCNVector3(x: 0.08749959, y: -0.03475155, z: -0.09906833),
SCNVector3(x: 0.08527064, y: -0.04331201, z: -0.10032329),
SCNVector3(x: 0.08125973, y: -0.04962304, z: -0.10258152),
SCNVector3(x: 0.07674095, y: -0.05456349, z: -0.10512567),
SCNVector3(x: 0.07041831, y: -0.05790819, z: -0.10868551),
SCNVector3(x: 0.06373097, y: -0.05820452, z: -0.11245064),
SCNVector3(x: 0.05844573, y: -0.05779012, z: -0.11542635),
SCNVector3(x: 0.05448552, y: -0.05334358, z: -0.11765605),
SCNVector3(x: 0.05290238, y: -0.04610482, z: -0.11854740),
SCNVector3(x: 0.05353430, y: -0.03637475, z: -0.11819161),
SCNVector3(x: 0.05589097, y: -0.02788102, z: -0.11686475),
SCNVector3(x: 0.05910149, y: -0.02275178, z: -0.11505718),
SCNVector3(x: 0.06234538, y: -0.02150976, z: -0.11323079),
SCNVector3(x: 0.06506948, y: -0.02217681, z: -0.11169703)
]
_ = model(vertices: vertices)
}
上面的代码失败的顶点数组示例：
vertices = [ SCNVector3(x: 0.08291423, y: -0.08406013, z: -0.60201955),
SCNVector3(x: 0.077855, y: -0.083336316, z: -0.60234916),
SCNVector3(x: 0.077855, y: -0.083336316, z: -0.60234916),
SCNVector3(x: 0.06817482, y: -0.08799789, z: -0.6029798),
SCNVector3(x: 0.055873748, y: -0.09737456, z: -0.6037812),
SCNVector3(x: 0.042388167, y: -0.108595274, z: -0.60465986),
SCNVector3(x: 0.031522393, y: -0.119523935, z: -0.6053677),
SCNVector3(x: 0.024102041, y: -0.13026507, z: -0.6058511),
SCNVector3(x: 0.021609604, y: -0.13820335, z: -0.6060136),
SCNVector3(x: 0.022751667, y: -0.14294992, z: -0.60593915),
SCNVector3(x: 0.025871918, y: -0.14491153, z: -0.6057359),
SCNVector3(x: 0.0338943, y: -0.14688163, z: -0.6052132),
SCNVector3(x: 0.041132875, y: -0.15027393, z: -0.60474163),
SCNVector3(x: 0.047307685, y: -0.15410759, z: -0.6043393),
SCNVector3(x: 0.054541387, y: -0.1566292, z: -0.603868),
SCNVector3(x: 0.06140149, y: -0.15919833, z: -0.60342115),
SCNVector3(x: 0.06551884, y: -0.16264887, z: -0.6031529)
]
----编辑3 ----
好吧，所以我为上面的代码制作了macOS版本（这是@ARGeo提出的解决方案，但做了一些细微的更改，例如使用任意数量的顶点），即使使用iOS，使用上述数组时也不会崩溃代码版本。但是什么也没渲染，我没有收到任何我不知道原因的错误消息。当添加行cameraNode.camera?.zFar = 1000以防由于裁剪而看不到时，程序将崩溃，并给出新的错误。如果zFar足够小（用zFar < 10测试），则不会崩溃，在这种情况下也不会渲染多边形。错误打印与-[MTLDebugDevice validateNewBufferArgs:options:]:467: failed assertion 'Cannot create buffer of zero length.'相同，但是调试导航器显示以下内容：
和堆栈跟踪的最后几行是这样的：
* thread #8, name = 'CVDisplayLink', queue = 'com.apple.scenekit.renderingQueue.SCNView0x101306480', stop reason = signal SIGABRT
* frame #0: 0x00007fff671b62c6 libsystem_kernel.dylib`__pthread_kill + 10
frame #1: 0x000000010053680d libsystem_pthread.dylib`pthread_kill + 284
frame #2: 0x00007fff671206a6 libsystem_c.dylib`abort + 127
frame #3: 0x00007fff670e920d libsystem_c.dylib`__assert_rtn + 324
frame #4: 0x00007fff3fd1b68e Metal`MTLReportFailure + 567
frame #5: 0x00007fff599f9d98 MetalTools`-[MTLDebugDevice validateNewBufferArgs:options:] + 207
frame #6: 0x00007fff599f9f28 MetalTools`-[MTLDebugDevice newBufferWithBytes:length:options:] + 107
frame #7: 0x00007fff462f265b SceneKit`-[SCNMTLResourceManager _bufferForData:bytesPerIndex:] + 414
frame #8: 0x00007fff462f29e0
这是如果您想自己尝试的代码。只需复制并粘贴到macOS项目中即可：
import SceneKit
import QuartzCore
class GameViewController: NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
let scene = SCNScene()
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
scene.rootNode.addChildNode(cameraNode)
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
// This line crashes the app! But w/o it the polygon plane would probably clip and be invisible.
cameraNode.camera?.zFar = 1000
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light!.type = .ambient
ambientLightNode.light!.intensity = 10000
ambientLightNode.light!.color = NSColor.darkGray
scene.rootNode.addChildNode(ambientLightNode)
func model(vertices: [SCNVector3]) -> SCNNode {
let polyDraw = draw(vertices: vertices)
let material = SCNMaterial()
material.diffuse.contents = NSColor.green
material.isDoubleSided = true
material.diffuse.contentsTransform = .init(m11: 0.1, m12: 0, m13: 0, m14: 0,
m21: 0, m22: 0.1, m23: 0, m24: 0,
m31: 0, m32: 0, m33: 0, m34: 0,
m41: 0, m42: 0, m43: 0, m44: 1)
material.diffuse.wrapS = .repeat
material.diffuse.wrapT = .repeat
polyDraw.materials = [material]
let node = SCNNode(geometry: polyDraw)
node.scale = SCNVector3(x: 200, y: 200, z: 200)
scene.rootNode.addChildNode(node)
return node
}
func draw(vertices: [SCNVector3]) -> SCNGeometry {
let normalsPerFace = 1
var indices: [Int32] = []
indices.append(Int32(vertices.count))
//Add the rest of the indices 0 to vertices.count-1
for i in 0 ... vertices.count-1 {
indices.append(Int32(i))
}
let source = SCNGeometrySource(vertices: vertices)
let vec = vertices.map { [SCNVector3](repeating: $0,
count: normalsPerFace) }.flatMap{ $0 }
let normals: [SCNVector3] = vec
let normalSource = SCNGeometrySource(normals: normals)
var cgps: [CGPoint] = []
vertices.forEach { (vertex) in
cgps.append(CGPoint(x: CGFloat(vertex.x), y: CGFloat(vertex.y)))
}
let textcoord = SCNGeometrySource(textureCoordinates: cgps)
let data = Data(bytes: indices,
count: indices.count * MemoryLayout<Int32>.size)
let element = SCNGeometryElement(data: data,
primitiveType: .polygon,
primitiveCount: 1,
bytesPerIndex: MemoryLayout<Int32>.size)
return SCNGeometry(sources: [source, normalSource, textcoord], elements: [element])
}
//Previous fail, now success with ARGeo's code
// let vertices = [SCNVector3(x: 0.08866002, y: -0.00773552, z: -0.09841499),
// SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
// SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
// SCNVector3(x: 0.08846086, y: -0.02434851, z: -0.09852711),
// SCNVector3(x: 0.08749959, y: -0.03475155, z: -0.09906833),
// SCNVector3(x: 0.08527064, y: -0.04331201, z: -0.10032329),
// SCNVector3(x: 0.08125973, y: -0.04962304, z: -0.10258152),
// SCNVector3(x: 0.07674095, y: -0.05456349, z: -0.10512567),
// SCNVector3(x: 0.07041831, y: -0.05790819, z: -0.10868551),
// SCNVector3(x: 0.06373097, y: -0.05820452, z: -0.11245064),
// SCNVector3(x: 0.05844573, y: -0.05779012, z: -0.11542635),
// SCNVector3(x: 0.05448552, y: -0.05334358, z: -0.11765605),
// SCNVector3(x: 0.05290238, y: -0.04610482, z: -0.11854740),
// SCNVector3(x: 0.05353430, y: -0.03637475, z: -0.11819161),
// SCNVector3(x: 0.05589097, y: -0.02788102, z: -0.11686475),
// SCNVector3(x: 0.05910149, y: -0.02275178, z: -0.11505718),
// SCNVector3(x: 0.06234538, y: -0.02150976, z: -0.11323079),
// SCNVector3(x: 0.06506948, y: -0.02217681, z: -0.11169703)
// ]
//Array which fails when the cameras zFar property
//is too big (>10 or something).
//If zFar is small enough it does not crash,
//but then nothing is rendered.
let vertices = [ SCNVector3(x: 0.08291423, y: -0.08406013, z: -0.60201955),
SCNVector3(x: 0.077855, y: -0.083336316, z: -0.60234916),
SCNVector3(x: 0.077855, y: -0.083336316, z: -0.60234916),
SCNVector3(x: 0.06817482, y: -0.08799789, z: -0.6029798),
SCNVector3(x: 0.055873748, y: -0.09737456, z: -0.6037812),
SCNVector3(x: 0.042388167, y: -0.108595274, z: -0.60465986),
SCNVector3(x: 0.031522393, y: -0.119523935, z: -0.6053677),
SCNVector3(x: 0.024102041, y: -0.13026507, z: -0.6058511),
SCNVector3(x: 0.021609604, y: -0.13820335, z: -0.6060136),
SCNVector3(x: 0.022751667, y: -0.14294992, z: -0.60593915),
SCNVector3(x: 0.025871918, y: -0.14491153, z: -0.6057359),
SCNVector3(x: 0.0338943, y: -0.14688163, z: -0.6052132),
SCNVector3(x: 0.041132875, y: -0.15027393, z: -0.60474163),
SCNVector3(x: 0.047307685, y: -0.15410759, z: -0.6043393),
SCNVector3(x: 0.054541387, y: -0.1566292, z: -0.603868),
SCNVector3(x: 0.06140149, y: -0.15919833, z: -0.60342115),
SCNVector3(x: 0.06551884, y: -0.16264887, z: -0.6031529)
]
_ = model(vertices: vertices)
let scnView = self.view as! SCNView
scnView.scene = scene
scnView.allowsCameraControl = true
scnView.showsStatistics = true
scnView.backgroundColor = NSColor.darkGray
}
}
我不知道是什么导致了此问题，因为似乎某些内部渲染出错了。我对调试也不是很有经验，所以我将不胜感激，希望对您有所帮助。
1 个答案:
答案 0 :(得分：1)
解决方案（复制并粘贴此macOS应用代码以在ViewController.swift中进行测试）：
import SceneKit
class ViewController: NSViewController, SCNSceneRendererDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let scene = SCNScene()
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.camera?.zFar = 1000
scene.rootNode.addChildNode(cameraNode)
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
let scnView = self.view as! SCNView
scnView.scene = scene
scnView.delegate = self
scnView.allowsCameraControl = true
scnView.showsStatistics = true
scnView.backgroundColor = NSColor.darkGray
func model( v01: SCNVector3,
v02: SCNVector3,
v03: SCNVector3,
v04: SCNVector3,
v05: SCNVector3,
v06: SCNVector3,
v07: SCNVector3,
v08: SCNVector3,
v09: SCNVector3,
v10: SCNVector3,
v11: SCNVector3,
v12: SCNVector3,
v13: SCNVector3,
v14: SCNVector3,
v15: SCNVector3,
v16: SCNVector3,
v17: SCNVector3,
v18: SCNVector3) -> SCNNode {
let polyDraw = draw(vector01: v01,
vector02: v02,
vector03: v03,
vector04: v04,
vector05: v05,
vector06: v06,
vector07: v07,
vector08: v08,
vector09: v09,
vector10: v10,
vector11: v11,
vector12: v12,
vector13: v13,
vector14: v14,
vector15: v15,
vector16: v16,
vector17: v17,
vector18: v18)
let material = SCNMaterial()
material.diffuse.contents = NSColor.green
material.isDoubleSided = true
polyDraw.materials = [material]
let node = SCNNode(geometry: polyDraw)
node.scale = SCNVector3(x: 200, y: 200, z: 200)
scene.rootNode.addChildNode(node)
return node
}
func draw(vector01: SCNVector3,
vector02: SCNVector3,
vector03: SCNVector3,
vector04: SCNVector3,
vector05: SCNVector3,
vector06: SCNVector3,
vector07: SCNVector3,
vector08: SCNVector3,
vector09: SCNVector3,
vector10: SCNVector3,
vector11: SCNVector3,
vector12: SCNVector3,
vector13: SCNVector3,
vector14: SCNVector3,
vector15: SCNVector3,
vector16: SCNVector3,
vector17: SCNVector3,
vector18: SCNVector3) -> SCNGeometry {
let normalsPerFace = 1
let indices: [Int32] = [18, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17]
let source = SCNGeometrySource(vertices: [vector01,
vector02,
vector03,
vector04,
vector05,
vector06,
vector07,
vector08,
vector09,
vector10,
vector11,
vector12,
vector13,
vector14,
vector15,
vector16,
vector17,
vector18])
let vec = [vector01, vector02, vector03,
vector04, vector05, vector06,
vector07, vector08, vector09,
vector10, vector11, vector12,
vector13, vector14, vector15,
vector16, vector17, vector18].map { [SCNVector3](repeating: $0,
count: normalsPerFace) }.flatMap{ $0 }
let normals: [SCNVector3] = vec
let normalSource = SCNGeometrySource(normals: normals)
let point01 = CGPoint(x: CGFloat(vector01.x), y: CGFloat(vector01.y))
let point02 = CGPoint(x: CGFloat(vector02.x), y: CGFloat(vector02.y))
let point03 = CGPoint(x: CGFloat(vector03.x), y: CGFloat(vector03.y))
let point04 = CGPoint(x: CGFloat(vector04.x), y: CGFloat(vector04.y))
let point05 = CGPoint(x: CGFloat(vector05.x), y: CGFloat(vector05.y))
let point06 = CGPoint(x: CGFloat(vector06.x), y: CGFloat(vector06.y))
let point07 = CGPoint(x: CGFloat(vector07.x), y: CGFloat(vector07.y))
let point08 = CGPoint(x: CGFloat(vector08.x), y: CGFloat(vector08.y))
let point09 = CGPoint(x: CGFloat(vector09.x), y: CGFloat(vector09.y))
let point10 = CGPoint(x: CGFloat(vector10.x), y: CGFloat(vector10.y))
let point11 = CGPoint(x: CGFloat(vector11.x), y: CGFloat(vector11.y))
let point12 = CGPoint(x: CGFloat(vector12.x), y: CGFloat(vector12.y))
let point13 = CGPoint(x: CGFloat(vector13.x), y: CGFloat(vector13.y))
let point14 = CGPoint(x: CGFloat(vector14.x), y: CGFloat(vector14.y))
let point15 = CGPoint(x: CGFloat(vector15.x), y: CGFloat(vector15.y))
let point16 = CGPoint(x: CGFloat(vector16.x), y: CGFloat(vector16.y))
let point17 = CGPoint(x: CGFloat(vector17.x), y: CGFloat(vector17.y))
let point18 = CGPoint(x: CGFloat(vector18.x), y: CGFloat(vector18.y))
let texCoord = SCNGeometrySource(textureCoordinates:
[point01, point02, point03, point04, point05, point06,
point07, point08, point09, point10, point11, point12,
point13, point14, point15, point16, point17, point18])
let data = Data(bytes: indices,
count: indices.count * MemoryLayout<Int32>.size)
let element = SCNGeometryElement(data: data,
primitiveType: .polygon,
primitiveCount: 1,
bytesPerIndex: MemoryLayout<Int32>.size)
let geometry = SCNGeometry(sources: [source, normalSource, texCoord],
elements: [element])
return geometry
}
_ = model(v01: SCNVector3(x: 0.08866002, y: -0.00773552, z: -0.09841499),
v02: SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
v03: SCNVector3(x: 0.08873053, y: -0.01492687, z: -0.09837532),
v04: SCNVector3(x: 0.08846086, y: -0.02434851, z: -0.09852711),
v05: SCNVector3(x: 0.08749959, y: -0.03475155, z: -0.09906833),
v06: SCNVector3(x: 0.08527064, y: -0.04331201, z: -0.10032329),
v07: SCNVector3(x: 0.08125973, y: -0.04962304, z: -0.10258152),
v08: SCNVector3(x: 0.07674095, y: -0.05456349, z: -0.10512567),
v09: SCNVector3(x: 0.07041831, y: -0.05790819, z: -0.10868551),
v10: SCNVector3(x: 0.06373097, y: -0.05820452, z: -0.11245064),
v11: SCNVector3(x: 0.05844573, y: -0.05779012, z: -0.11542635),
v12: SCNVector3(x: 0.05448552, y: -0.05334358, z: -0.11765605),
v13: SCNVector3(x: 0.05290238, y: -0.04610482, z: -0.11854740),
v14: SCNVector3(x: 0.05353430, y: -0.03637475, z: -0.11819161),
v15: SCNVector3(x: 0.05589097, y: -0.02788102, z: -0.11686475),
v16: SCNVector3(x: 0.05910149, y: -0.02275178, z: -0.11505718),
v17: SCNVector3(x: 0.06234538, y: -0.02150976, z: -0.11323079),
v18: SCNVector3(x: 0.06506948, y: -0.02217681, z: -0.11169703))
}
}
有用的信息：
在3D图形中，使用多边形几何体的最佳方法也是最可预测的方法，首先是使用三面（三角形）和四面（四边形）面。有时，在极少数情况下，您可以使用五面脸，但这会导致您产生阴影伪影。
Bad cases可能会导致SceneKit / Metal中的错误，是：
- 层状面孔
- 非流形几何
- 非平面的面孔（您的情况）
- 凹面
- “由内而外”的面孔，即连接顺序错误（您的情况）
- 带孔的脸
- 边长为零的面
- 等...
我还要说的一件事是：在渲染阶段，所有多边形总是变成三角形。如果渲染器或渲染引擎无法完成此转换，则会出现错误。
查看如何将四个面的多边形有效地连接起来以形成复杂的对象：
PS （用于ARKit）。
camera.zFar 。
let currentFrame = sceneView.session.currentFrame
let node = SCNNode()
node.camera = SCNCamera()
var translation = matrix_identity_float4x4
translation.columns.3.z = -0.1 /* 10 cm */
node.simdTransform = matrix_multiply((currentFrame?.camera.transform)!,
translation)
node.camera?.zFar = 1000 /* Set no more than 1000 meters */
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