Use simple pinch end threshold avoiding repeated pinch starts

Author: mrxz

src/components/hand-tracking-controls.js

@@ -43,7 +43,7 @@ var THUMB_TIP_INDEX = 4;
 var INDEX_TIP_INDEX = 9;
 
 var PINCH_START_DISTANCE = 0.015;
-var PINCH_END_PERCENTAGE = 0.1;
+var PINCH_END_DISTANCE = 0.02;
 
 /**
  * Controls for hand tracking
@@ -282,12 +282,11 @@ module.exports.Component = registerComponent('hand-tracking-controls', {
 
       if (distance < PINCH_START_DISTANCE && this.isPinched === false) {
         this.isPinched = true;
-        this.pinchDistance = distance;
         pinchEventDetail.position.copy(indexTipPosition).add(thumbTipPosition).multiplyScalar(0.5);
         this.el.emit('pinchstarted', pinchEventDetail);
       }
 
-      if (distance > (this.pinchDistance + this.pinchDistance * PINCH_END_PERCENTAGE) && this.isPinched === true) {
+      if (distance > PINCH_END_DISTANCE && this.isPinched === true) {
         this.isPinched = false;
         pinchEventDetail.position.copy(indexTipPosition).add(thumbTipPosition).multiplyScalar(0.5);
         this.el.emit('pinchended', pinchEventDetail);