Improve Touch (Part 2 - Multitouch)

Sources/UIApplication+handleSDLEvents.swift

@@ -16,8 +16,8 @@ extension UIApplication {
         while SDL_PollEvent(&e) == 1 {
 
             #if os(Android)
-            if let uievent = UIEvent.from(e) {
-                sendEvent(uievent)
+            if let uiEvent = UIEvent.from(e) {
+                sendEvent(uiEvent)
                 break
             }
             #endif

Sources/UIEvent+fromSDL_Event.swift

@@ -0,0 +1,127 @@
+//
+//  UIEvent+fromSDL_Event.swift
+//  UIKit
+//
+//  Created by Geordie Jay on 05.11.18.
+//  Copyright © 2018 flowkey. All rights reserved.
+//
+
+import JNI
+import SDL
+
+extension UIEvent {
+    static func from(_ event: SDL_Event) -> UIEvent? {
+        switch SDL_EventType(event.type) {
+        case SDL_FINGERDOWN:
+            let newTouch = UITouch(
+                touchId: Int(event.tfinger.fingerId),
+                at: CGPoint(
+                    x: CGFloat(event.tfinger.x),
+                    y: CGFloat(event.tfinger.y)
+                ),
+                timestamp: event.timestampInSeconds
+            )
+
+            guard let existingTouchEvent = UIEvent.activeEvents.first(where: { $0.allTouches != nil }) else {
+                return UIEvent(touch: newTouch)
+            }
+
+            assert(!existingTouchEvent.allTouches!.contains(where: { $0.touchId == event.tfinger.fingerId }),
+                "The active event already has a touch with this fingerId, this should be impossible")
+
+            existingTouchEvent.allTouches!.insert(newTouch)
+            return existingTouchEvent
+
+        case SDL_FINGERMOTION:
+            if
+                let existingTouchEvent = UIEvent.activeEvents.first(where: { $0.allTouches != nil }),
+                let matchingTouch = existingTouchEvent.allTouches?.first(where: { $0.touchId == event.tfinger.fingerId })
+            {
+                matchingTouch.timestamp = event.timestampInSeconds
+                matchingTouch.phase = .moved
+                matchingTouch.updateAbsoluteLocation(.from(event.tfinger))
+                return existingTouchEvent
+            } else {
+                assertionFailure("Got a motion event for a touch we know nothing about")
+                return nil
+            }
+
+        case SDL_FINGERUP:
+            if
+                let firstExistingEvent = UIEvent.activeEvents.first(where: { $0.allTouches != nil }),
+                let matchingTouch = firstExistingEvent.allTouches?.first(where: { $0.touchId == event.tfinger.fingerId })
+            {
+                matchingTouch.timestamp = event.timestampInSeconds
+                matchingTouch.phase = .ended
+                return firstExistingEvent
+            } else {
+                assertionFailure("Got a finger up event for a touch we know nothing about")
+                return nil
+            }
+
+        default:
+            return nil
+        }
+    }
+}
+
+extension UIEvent: CustomStringConvertible {
+    public var description: String {
+        let baseText = "UIEvent:"
+        guard let allTouches = self.allTouches else {
+            return baseText + " no touches"
+        }
+
+        return baseText + "\n" + allTouches.map { $0.description }.joined(separator: ",\n")
+    }
+}
+
+extension UITouch: CustomStringConvertible {
+    public var description: String {
+        return "TouchID: \(self.touchId), timestamp: \(self.timestamp)"
+    }
+}
+
+@_cdecl("Java_org_libsdl_app_SDLActivity_onNativeTouchUIKit")
+public func onNativeTouch(
+    env: UnsafeMutablePointer<JNIEnv>,
+    view: JavaObject,
+    touchDeviceID: JavaInt,
+    pointerFingerID: JavaInt,
+    action: JavaInt,
+    x: JavaFloat,
+    y: JavaFloat,
+    pressure: JavaFloat,
+    timestamp: JavaLong
+) {
+    guard let eventType = SDL_EventType.from(androidAction: action) else { return }
+
+    var event = SDL_Event(tfinger:
+        SDL_TouchFingerEvent(
+            type: eventType.rawValue,
+            timestamp: UInt32(timestamp), // the Android system provides timestamps in ms
+            touchId: Int64(touchDeviceID), // seems to remain constant but actual value depends on phone/tablet
+            fingerId: Int64(pointerFingerID),
+            x: x / Float(UIScreen.main.scale),
+            y: y / Float(UIScreen.main.scale),
+            dx: 0, // Not used in UIKit cross platform:
+            dy: 0, // Instead, we do these calculations in our UIGestureRecognizers etc.
+            pressure: pressure
+        )
+    )
+
+    // Add the event to SDL's event stack
+    // Don't use SDL_PushEvent because that overrides `event.timestamp` with its own:
+    SDL_PeepEvents(&event, 1, SDL_ADDEVENT, 0, 0)
+}
+
+extension SDL_EventType {
+    public static func from(androidAction: JavaInt) -> SDL_EventType? {
+        switch androidAction {
+        case 0, 5: return SDL_FINGERDOWN
+        case 1, 6: return SDL_FINGERUP
+        case 2: return SDL_FINGERMOTION
+        default: return nil
+        }
+    }
+}

Sources/UIWindow.swift

@@ -25,34 +25,37 @@ public class UIWindow: UIView {
     }
 
     public func sendEvent(_ event: UIEvent) {
-        guard
-            let allTouches = event.allTouches,
-            let currentTouch = allTouches.first,
-            let hitView = currentTouch.view ?? hitTest(currentTouch.location(in: nil), with: nil)
-        else { return }
+        guard let allTouches = event.allTouches else { return }
+        UIEvent.activeEvents.insert(event)
 
-        switch currentTouch.phase {
-        case .began:
-            UIEvent.activeEvents.insert(event)
-            currentTouch.view = hitView
-            currentTouch.gestureRecognizers = hitView.getRecognizerHierachy()
+        for touch in allTouches {
+            guard let hitView = touch.view ?? hitTest(touch.location(in: nil), with: nil) else { return }
 
-            currentTouch.runTouchActionOnRecognizerHierachy { $0.touchesBegan(allTouches, with: event) }
-            hitView.touchesBegan(allTouches, with: event)
+            switch touch.phase {
+            case .began:
+                touch.view = hitView
+                touch.gestureRecognizers = hitView.getRecognizerHierachy()
 
-        case .moved:
-            currentTouch.runTouchActionOnRecognizerHierachy { $0.touchesMoved(allTouches, with: event) }
-            if !currentTouch.hasBeenCancelledByAGestureRecognizer {
-                hitView.touchesMoved(allTouches, with: event)
-            }
+                touch.runTouchActionOnRecognizerHierachy { $0.touchesBegan([touch], with: event) }
+                hitView.touchesBegan([touch], with: event)
 
-        case .ended:
-            currentTouch.runTouchActionOnRecognizerHierachy { $0.touchesEnded(allTouches, with: event) }
-            if !currentTouch.hasBeenCancelledByAGestureRecognizer {
-                hitView.touchesEnded(allTouches, with: event)
-            }
+            case .moved:
+                touch.runTouchActionOnRecognizerHierachy { $0.touchesMoved([touch], with: event) }
+                if !touch.hasBeenCancelledByAGestureRecognizer {
+                    hitView.touchesMoved([touch], with: event)
+                }
 
-            UIEvent.activeEvents.remove(event)
+            case .ended:
+                touch.runTouchActionOnRecognizerHierachy { $0.touchesEnded([touch], with: event) }
+                if !touch.hasBeenCancelledByAGestureRecognizer {
+                    hitView.touchesEnded([touch], with: event)
+                }
+
+                event.allTouches?.remove(touch)
+                if event.allTouches?.isEmpty == true {
+                    UIEvent.activeEvents.remove(event)
+                }
+            }
         }
     }
 }

UIKit.xcodeproj/project.pbxproj

@@ -326,7 +326,6 @@
 		5C1F06AE1F3210F200EFF087 /* UIViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = UIViewController.swift; path = Sources/UIViewController.swift; sourceTree = SOURCE_ROOT; };
 		5C2714A11F2A3FC50026BBA9 /* SDL+JNIExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "SDL+JNIExtensions.swift"; sourceTree = "<group>"; };
 		5C27E7AE1ECB2F6500F5020D /* UIKit.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = UIKit.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		5C27E7B21ECB2F6500F5020D /* Mac-Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; name = "Mac-Info.plist"; path = "../Sources/Mac-Info.plist"; sourceTree = "<group>"; };
 		5C27E7B71ECB2F6500F5020D /* UIKitTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = UIKitTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		5C27E7BE1ECB2F6500F5020D /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		5C27E7D21ECB2F9100F5020D /* Cocoa.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Cocoa.framework; path = System/Library/Frameworks/Cocoa.framework; sourceTree = SDKROOT; };
@@ -572,7 +571,6 @@
 				5C27E7B01ECB2F6500F5020D /* UIKit */,
 				5C27E7BB1ECB2F6500F5020D /* UIKitTests */,
 				83C18F391F0FB486008FEA07 /* Resources */,
-				5C27E7E61ECB2FE000F5020D /* zSupporting Files */,
 			);
 			sourceTree = "<group>";
 		};
@@ -700,15 +698,6 @@
 			name = Frameworks;
 			sourceTree = "<group>";
 		};
-		5C27E7E61ECB2FE000F5020D /* zSupporting Files */ = {
-			isa = PBXGroup;
-			children = (
-				5C27E7B21ECB2F6500F5020D /* Mac-Info.plist */,
-			);
-			name = "zSupporting Files";
-			path = UIKit;
-			sourceTree = "<group>";
-		};
 		5C27E7F51ECB301900F5020D /* SDL */ = {
 			isa = PBXGroup;
 			children = (