From 3c04f54e7509b08c36eff7311f16a3f6b636c391 Mon Sep 17 00:00:00 2001
From: "Anthony J. Thibault" <tony@highfidelity.io>
Date: Tue, 31 Jan 2017 18:22:38 -0800
Subject: [PATCH] more fixes to third person tablet usage.

---
 scripts/system/libraries/WebTablet.js | 31 +++++++++++++--------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/scripts/system/libraries/WebTablet.js b/scripts/system/libraries/WebTablet.js
index 52912337a1..75ca2e514f 100644
--- a/scripts/system/libraries/WebTablet.js
+++ b/scripts/system/libraries/WebTablet.js
@@ -24,6 +24,7 @@ var CAMERA_MATRIX = -7;
 var ROT_Y_180 = {x: 0, y: 1, z: 0, w: 0};
 var TABLET_TEXTURE_RESOLUTION = { x: 480, y: 706 };
 var INCHES_TO_METERS = 1 / 39.3701;
+var NO_HANDS = -1;
 
 var TABLET_URL = Script.resourcesPath() + "meshes/tablet-with-home-button.fbx";
 
@@ -35,18 +36,21 @@ var TABLET_MODEL_PATH = "http://hifi-content.s3.amazonaws.com/alan/dev/tablet-wi
 //    * position - position in front of the user
 //    * rotation - rotation of entity so it faces the user.
 function calcSpawnInfo(hand, height) {
-    var noHands = -1;
     var finalPosition;
-    if (HMD.active && hand !== noHands) {
+
+    var headPos = (HMD.active && Camera.mode === "first person") ? HMD.position : Camera.position;
+    var headRot = (HMD.active && Camera.mode === "first person") ? HMD.orientation : Camera.orientation;
+
+    if (HMD.active && hand !== NO_HANDS) {
         var handController = getControllerWorldLocation(hand, true);
         var controllerPosition = handController.position;
 
         // compute the angle of the chord with length (height / 2)
-        var theta = Math.asin(height / (2 * Vec3.distance(HMD.position, controllerPosition)));
+        var theta = Math.asin(height / (2 * Vec3.distance(headPos, controllerPosition)));
 
         // then we can use this angle to rotate the vector between the HMD position and the center of the tablet.
         // this vector, u, will become our new look at direction.
-        var d = Vec3.normalize(Vec3.subtract(HMD.position, controllerPosition));
+        var d = Vec3.normalize(Vec3.subtract(headPos, controllerPosition));
         var w = Vec3.normalize(Vec3.cross(Y_AXIS, d));
         var q = Quat.angleAxis(theta * (180 / Math.PI), w);
         var u = Vec3.multiplyQbyV(q, d);
@@ -64,8 +68,8 @@ function calcSpawnInfo(hand, height) {
             rotation: lookAtRot
         };
     } else {
-        var front = Quat.getFront(Camera.orientation);
-        finalPosition = Vec3.sum(Camera.position, Vec3.multiply(0.6, front));
+        var front = Quat.getFront(headRot);
+        finalPosition = Vec3.sum(headPos, Vec3.multiply(0.6, front));
         var orientation = Quat.lookAt({x: 0, y: 0, z: 0}, front, {x: 0, y: 1, z: 0});
         return {
             position: finalPosition,
@@ -238,7 +242,6 @@ WebTablet.prototype.destroy = function () {
 
 WebTablet.prototype.geometryChanged = function (geometry) {
     if (!HMD.active) {
-        var NO_HANDS = -1;
         var tabletProperties = {};
         // compute position, rotation & parentJointIndex of the tablet
         this.calculateTabletAttachmentProperties(NO_HANDS, tabletProperties);
@@ -294,7 +297,6 @@ WebTablet.prototype.onHmdChanged = function () {
         Controller.mouseReleaseEvent.connect(this.myMouseReleaseEvent);
     }
 
-    var NO_HANDS = -1;
     var tabletProperties = {};
     // compute position, rotation & parentJointIndex of the tablet
     this.calculateTabletAttachmentProperties(NO_HANDS, tabletProperties);
@@ -377,17 +379,14 @@ WebTablet.prototype.mousePressEvent = function (event) {
 };
 
 WebTablet.prototype.cameraModeChanged = function (newMode) {
-    // reposition the tablet, after a small delay.
+    // reposition the tablet.
     // This allows HMD.position to reflect the new camera mode.
     if (HMD.active) {
         var self = this;
-        Script.setTimeout(function () {
-            var NO_HANDS = -1;
-            var tabletProperties = {};
-            // compute position, rotation & parentJointIndex of the tablet
-            self.calculateTabletAttachmentProperties(NO_HANDS, tabletProperties);
-            Entities.editEntity(self.tabletEntityID, tabletProperties);
-        }, 10);
+        var tabletProperties = {};
+        // compute position, rotation & parentJointIndex of the tablet
+        self.calculateTabletAttachmentProperties(NO_HANDS, tabletProperties);
+        Entities.editEntity(self.tabletEntityID, tabletProperties);
     }
 };