From 83516c5cf28d5f3b5e0af7ba8921e8e676260067 Mon Sep 17 00:00:00 2001
From: Paul Elliott <paul@dyadmed.com>
Date: Sat, 10 Apr 2021 13:20:06 -0400
Subject: [PATCH] Add 3 or more finger touch pan + zoom support

---
 CameraSpinControls.js | 112 +++++++++++++++++++++---------------------
 1 file changed, 55 insertions(+), 57 deletions(-)

diff --git a/CameraSpinControls.js b/CameraSpinControls.js
index 3ccccfc..ff32441 100644
--- a/CameraSpinControls.js
+++ b/CameraSpinControls.js
@@ -802,45 +802,40 @@ CameraSpinControls = function ( camera, domElement ) {
 
 		event.preventDefault();
 
-		switch ( event.touches.length ) {
+		if ( event.touches.length === 1 ) {
+			// 1 finger touch: rotate
+			if ( scope.enableRotate === false ) return;
 
-			case 1:	// one-fingered touch: rotate
-
-				if ( scope.enableRotate === false ) return;
-
-				state = STATE.ROTATE;
-				
-				if ( scope.startTrackballScreenCenter ) {
-
-					scope.target.setFromMatrixPosition(scope.trackballToObject);
-					var startDistance = scope.target.length();
-					scope.target.set(0, 0, -startDistance);
-					scope.target.applyQuaternion(scope.object.quaternion);
-					scope.target.add(scope.object.position);
-					scope.setTargetPosition(scope.target);
-
-				}
-
-				break;
-
-			case 2:	// two-fingered touch: dolly-pan
+			state = STATE.ROTATE;
+			
+			if ( scope.startTrackballScreenCenter ) {
 
-				if ( scope.enableZoom === false 
-					&& scope.enablePan === false 
-					&& scope.enableRotate === false) return;
+				scope.target.setFromMatrixPosition(scope.trackballToObject);
+				var startDistance = scope.target.length();
+				scope.target.set(0, 0, -startDistance);
+				scope.target.applyQuaternion(scope.object.quaternion);
+				scope.target.add(scope.object.position);
+				scope.setTargetPosition(scope.target);
 
-				handleTouchStartDollyPanRoll( event );
+			}
 
-				state = STATE.TOUCH_DOLLY_PAN;
+		} else if ( event.touches.length >= 2 ) {
+			
+			// 2+ finger touch: dolly-pan
+		
+			if ( scope.enableZoom === false 
+				&& scope.enablePan === false 
+				&& scope.enableRotate === false) return;
 
-				scope.spinControl.cancelSpin();
-				scope.spinControl.enabled = false;
+			handleTouchStartDollyPanRoll( event );
 
-				break;
+			state = STATE.TOUCH_DOLLY_PAN;
 
-			default:
+			scope.spinControl.cancelSpin();
+			scope.spinControl.enabled = false;
+		} else {
 
-				state = STATE.NONE;
+			state = STATE.NONE;
 
 		}
 
@@ -859,27 +854,19 @@ CameraSpinControls = function ( camera, domElement ) {
 		event.preventDefault();
 		event.stopPropagation();
 
-		switch ( event.touches.length ) {
-
-			// case 1: // one-fingered touch: rotate
-
-			// 	if ( scope.enableRotate === false ) return;
-
-			// 	break;
+		if ( event.touches.length >= 2) {
 
-			case 2: // two-fingered touch: dolly-pan
+			// dolly-pan
+			if ( scope.enableZoom === false && scope.enablePan === false ) return;
 
-				if ( scope.enableZoom === false && scope.enablePan === false ) return;
+			handleTouchMoveDollyPanRoll( event );
 
-				handleTouchMoveDollyPanRoll( event );
-
-				break;
-
-			default:
+		} else {
 
-				state = STATE.NONE;
+			state = STATE.NONE;
 
 		}
+		// 1 finger touch events are consumed by underlying SpinControls
 
 	}
 
@@ -887,30 +874,41 @@ CameraSpinControls = function ( camera, domElement ) {
 
 		if ( scope.enabled === false ) return;
 
-		if( event.touches.length === 1 ) {
+		if( event.touches.length === 0 ) {
+			
+			state = STATE.NONE;
+			endEvent.state = state;
+			scope.dispatchEvent( endEvent );
+
+		} else if( event.touches.length === 1 ) {
+
+			if ( scope.startTrackballScreenCenter ) {
+
+				// Set pivot point back to center if going from 2+ fingers to 1
+				scope.target.setFromMatrixPosition(scope.trackballToObject);
+				var startDistance = scope.target.length();
+				scope.target.set(0, 0, -startDistance);
+				scope.target.applyQuaternion(scope.object.quaternion);
+				scope.target.add(scope.object.position);
+				scope.setTargetPosition(scope.target);
+
+			}
 			
 			state = STATE.ROTATE;
 			scope.spinControl.enabled = true;
 			scope.spinControl.handleTouchStart( event );
 
-		} else if( event.touches.length === 0 ) {
-		// } else {
-			
-			state = STATE.NONE;
-			endEvent.state = state;
-			scope.dispatchEvent( endEvent );
+		} else if( event.touches.length >= 2 ) {
+
+			handleTouchStartDollyPanRoll( event );
 
 		}
-		
 
 	}
 
 	function onContextMenu( event ) {
 
 		event.preventDefault();
-		// if ( scope.enabled === false ) return;
-
-		// event.preventDefault();
 
 	}