From 55b7c2d767f08d674eba5fc8eaa823e237b991b2 Mon Sep 17 00:00:00 2001
From: Seth Alves <seth.alves@gmail.com>
Date: Wed, 5 Jul 2017 15:50:05 -0700
Subject: [PATCH] avoid doing a lot of work during mouse-move event-handlers

---
 scripts/system/controllers/grab.js    | 27 +++++++++++++-------------
 scripts/system/libraries/WebTablet.js | 28 +++++++++++++++++++++++----
 2 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/scripts/system/controllers/grab.js b/scripts/system/controllers/grab.js
index 9f06aac3a6..da8add5117 100644
--- a/scripts/system/controllers/grab.js
+++ b/scripts/system/controllers/grab.js
@@ -447,15 +447,7 @@ Grabber.prototype.releaseEvent = function(event) {
     }
 };
 
-Grabber.prototype.moveEvent = function(event) {
-    // during the handling of the event, do as little as possible.  We save the updated mouse position,
-    // and start a timer to react to the change.  If more changes arrive before the timer fires, only
-    // the last update will be considered.  This is done to avoid backing-up Qt's event queue.
-    if (!this.isGrabbing) {
-        return;
-    }
-    mouse.updateDrag(event);
-
+Grabber.prototype.scheduleMouseMoveProcessor = function(event) {
     var _this = this;
     if (!this.moveEventTimer) {
         this.moveEventTimer = Script.setTimeout(function() {
@@ -464,7 +456,19 @@ Grabber.prototype.moveEvent = function(event) {
     }
 };
 
+Grabber.prototype.moveEvent = function(event) {
+    // during the handling of the event, do as little as possible.  We save the updated mouse position,
+    // and start a timer to react to the change.  If more changes arrive before the timer fires, only
+    // the last update will be considered.  This is done to avoid backing-up Qt's event queue.
+    if (!this.isGrabbing) {
+        return;
+    }
+    mouse.updateDrag(event);
+    this.scheduleMouseMoveProcessor();
+};
+
 Grabber.prototype.moveEventProcess = function() {
+    this.moveEventTimer = null;
     // see if something added/restored gravity
     var entityProperties = Entities.getEntityProperties(this.entityID);
     if (!entityProperties || !entityProperties.gravity) {
@@ -559,10 +563,7 @@ Grabber.prototype.moveEventProcess = function() {
         Entities.updateAction(this.entityID, this.actionID, actionArgs);
     }
 
-    var _this = this;
-    this.moveEventTimer = Script.setTimeout(function() {
-        _this.moveEventProcess();
-    }, DELAY_FOR_30HZ);
+    this.scheduleMouseMoveProcessor();
 };
 
 Grabber.prototype.keyReleaseEvent = function(event) {
diff --git a/scripts/system/libraries/WebTablet.js b/scripts/system/libraries/WebTablet.js
index b429a9f3ae..142ed6e7b6 100644
--- a/scripts/system/libraries/WebTablet.js
+++ b/scripts/system/libraries/WebTablet.js
@@ -14,8 +14,6 @@ Script.include(Script.resolvePath("../libraries/utils.js"));
 Script.include(Script.resolvePath("../libraries/controllers.js"));
 Script.include(Script.resolvePath("../libraries/Xform.js"));
 
-var VEC3_ZERO = {x: 0, y: 0, z: 0};
-var X_AXIS = {x: 1, y: 0, z: 0};
 var Y_AXIS = {x: 0, y: 1, z: 0};
 var DEFAULT_DPI = 34;
 var DEFAULT_WIDTH = 0.4375;
@@ -25,12 +23,13 @@ var CAMERA_MATRIX = -7;
 var ROT_Y_180 = {x: 0.0, y: 1.0, z: 0, w: 0};
 var ROT_LANDSCAPE = {x: 1.0, y: 1.0, z: 0, w: 0};
 var ROT_LANDSCAPE_WINDOW = {x: 0.0, y: 0.0, z: 0.0, w: 0};
-var ROT_IDENT = {x: 0, y: 0, z: 0, w: 1};
 var TABLET_TEXTURE_RESOLUTION = { x: 480, y: 706 };
 var INCHES_TO_METERS = 1 / 39.3701;
 var AVATAR_SELF_ID = "{00000000-0000-0000-0000-000000000001}";
 
 var NO_HANDS = -1;
+var DELAY_FOR_30HZ = 33; // milliseconds
+
 
 // will need to be recaclulated if dimensions of fbx model change.
 var TABLET_NATURAL_DIMENSIONS = {x: 33.797, y: 50.129, z: 2.269};
@@ -561,9 +560,29 @@ function rayIntersectPlane(planePosition, planeNormal, rayStart, rayDirection) {
     }
 }
 
+WebTablet.prototype.scheduleMouseMoveProcessor = function() {
+    var _this = this;
+    if (!this.moveEventTimer) {
+        this.moveEventTimer = Script.setTimeout(function() {
+            _this.mouseMoveProcessor();
+        }, DELAY_FOR_30HZ);
+    }
+};
+
 WebTablet.prototype.mouseMoveEvent = function (event) {
     if (this.dragging) {
-        var pickRay = Camera.computePickRay(event.x, event.y);
+        this.currentMouse = {
+            x: event.x,
+            y: event.y
+        };
+        this.scheduleMouseMoveProcessor();
+    }
+};
+
+WebTablet.prototype.mouseMoveProcessor = function () {
+    this.moveEventTimer = null;
+    if (this.dragging) {
+        var pickRay = Camera.computePickRay(this.currentMouse.x, this.currentMouse.y);
 
         // transform pickRay into camera local coordinates
         var invCameraXform = new Xform(Camera.orientation, Camera.position).inv();
@@ -582,6 +601,7 @@ WebTablet.prototype.mouseMoveEvent = function (event) {
                 localPosition: localPosition
             });
         }
+        this.scheduleMouseMoveProcessor();
     }
 };