Fix render glitches and support Spritekit, SceneKit and GLKit

Snap/Core/Infrastructure/Extension/UIView/UIView+Render.swift

@@ -1,16 +1,45 @@
 import UIKit
+import SpriteKit
+import SceneKit
+
+/**
+ Adds a static image view on top of all SCNViews, GLKViews and SKViews for the given view hierarchy so these can be captured. Returns the created views.
+ */
+func addImagesForRenderedViews(_ view: UIView) -> [UIView] {
+
+  func add(_ image: UIImage) -> [UIView] {
+    let imageView = UIImageView(image: image)
+    imageView.frame = view.bounds
+    view.addSubview(imageView)
+    return [imageView]
+  }
+
+  if let scnview = view as? SCNView {
+    return add(scnview.snapshot())
+  } else if let glview = view as? GLKView {
+    return add(glview.snapshot)
+  } else if let skview = view as? SKView {
+    return add(UIImage(cgImage: skview.texture(from: skview.scene!)!.cgImage()))
+  } else {
+    return view.subviews.flatMap(addImagesForRenderedViews)
+  }
+}
 
 extension UIView {
   /// Extract image data with the whole hierarchy from `UIView`
   func render() -> UIImage? {
+
+    // SpriteKit refuses to draw its hierarchy: render an image of the spritekit view and add it to the view to be able to capture it
+    let addedViews = addImagesForRenderedViews(self)
+    defer { addedViews.forEach { $0.removeFromSuperview() } }
+
     if #available(iOS 10.0, *) {
       let imageRendererFormat = UIGraphicsImageRendererFormat.default()
       imageRendererFormat.opaque = true
       let renderer = UIGraphicsImageRenderer(
         bounds: bounds
       )
       return renderer.image { context in
-        drawHierarchy(in: bounds, afterScreenUpdates: true)
         layer.render(in: context.cgContext)
       }
     }
@@ -21,7 +50,6 @@ extension UIView {
     UIGraphicsBeginImageContextWithOptions(bounds.size, false, 0.0)
 
     let context = UIGraphicsGetCurrentContext()!
-    drawHierarchy(in: bounds, afterScreenUpdates: true)
     layer.render(in: context)
     return UIGraphicsGetImageFromCurrentImageContext()
   }

SnapTests/SnapTests.swift

@@ -1,5 +1,7 @@
 import XCTest
 import UIKit
+import SpriteKit
+import SceneKit
 
 private final class SnapTests: XCTestCase {
 
@@ -34,8 +36,8 @@ private final class SnapTests: XCTestCase {
       UIColor.white.cgColor
     ]
     layer.locations = [0.0, 1.0]
-    layer.startPoint = CGPoint(x: 0.0, y: 1.0)
-    layer.endPoint = CGPoint(x: 0.0, y: 1.0)
+    layer.startPoint = CGPoint(x: 0.0, y: 0.0)
+    layer.endPoint = CGPoint(x: 1.0, y: 0.0)
 
     expect(layer).toMatchSnapshot()
   }
@@ -67,4 +69,51 @@ private final class SnapTests: XCTestCase {
 
     expect(view).toMatchSnapshot(for: .iPadDevices)
   }
+
+  func test_spritekit_view() {
+    let scene = SKScene(size: CGSize(width: 100, height: 100))
+    scene.backgroundColor = .yellow
+
+    let rect = SKShapeNode(rectOf: CGSize(width: 10, height: 10))
+    rect.fillColor = .red
+    rect.strokeColor = .clear
+    rect.position = CGPoint(x: 50, y: 50)
+    scene.addChild(rect)
+
+    let view = SKView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
+    view.presentScene(scene)
+
+    expect(view).toMatchSnapshot()
+  }
+
+  func test_scenekit_view() {
+    let scene = SCNScene()
+
+    // light
+    let lightNode = SCNNode()
+    lightNode.light = SCNLight()
+    lightNode.light!.type = .omni
+    lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
+    scene.rootNode.addChildNode(lightNode)
+
+    // cube
+    let cubeGeometry = SCNBox(width: 5, height: 5, length: 5, chamferRadius: 0)
+    cubeGeometry.firstMaterial!.diffuse.contents = UIColor.red
+    let cubeNode = SCNNode(geometry: cubeGeometry)
+    scene.rootNode.addChildNode(cubeNode)
+
+    // camera
+    let cameraNode = SCNNode()
+    cameraNode.camera = SCNCamera()
+    scene.rootNode.addChildNode(cameraNode)
+    cameraNode.position = SCNVector3(x: 10, y: 10, z: 10)
+    cameraNode.constraints = [SCNLookAtConstraint(target: cubeNode)]
+
+    let view = SCNView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
+    view.backgroundColor = .yellow
+    view.scene = scene
+
+    expect(view).toMatchSnapshot()
+  }
+
 }