From c41ce5d4845a3c1271b711e002fcbc704f5bddd1 Mon Sep 17 00:00:00 2001
From: David Rowe <david@ctrlaltstudio.com>
Date: Thu, 18 Oct 2018 17:10:48 +1300
Subject: [PATCH] Make tablet have priority over drawInFront overlays rendered
 behind it

---
 interface/src/Application.cpp          | 10 ++++++++++
 interface/src/Application.h            |  1 +
 interface/src/ui/overlays/Overlays.cpp |  9 ++++++---
 interface/src/ui/overlays/Overlays.h   |  6 +++++-
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 2dc3645be0..1bd6af2eba 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -8476,6 +8476,16 @@ QUuid Application::getTabletFrameID() const {
     return HMD->getCurrentTabletFrameID();
 }
 
+QVector<QUuid> Application::getTabletIDs() const {
+    // Most important overlays first. 
+    QVector<QUuid> result;
+    auto HMD = DependencyManager::get<HMDScriptingInterface>();
+    result << HMD->getCurrentTabletScreenID();
+    result << HMD->getCurrentHomeButtonID();
+    result << HMD->getCurrentTabletFrameID();
+    return result;
+}
+
 void Application::setAvatarOverrideUrl(const QUrl& url, bool save) {
     _avatarOverrideUrl = url;
     _saveAvatarOverrideUrl = save;
diff --git a/interface/src/Application.h b/interface/src/Application.h
index 75260b910f..c75c2e9efc 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -298,6 +298,7 @@ public:
     OverlayID getTabletScreenID() const;
     OverlayID getTabletHomeButtonID() const;
     QUuid getTabletFrameID() const; // may be an entity or an overlay
+    QVector<QUuid> getTabletIDs() const; // In order of most important IDs first.
 
     void setAvatarOverrideUrl(const QUrl& url, bool save);
     void clearAvatarOverrideUrl() { _avatarOverrideUrl = QUrl(); _saveAvatarOverrideUrl = false; }
diff --git a/interface/src/ui/overlays/Overlays.cpp b/interface/src/ui/overlays/Overlays.cpp
index de4ff94719..ea73edcab5 100644
--- a/interface/src/ui/overlays/Overlays.cpp
+++ b/interface/src/ui/overlays/Overlays.cpp
@@ -532,6 +532,8 @@ RayToOverlayIntersectionResult Overlays::findRayIntersectionVector(const PickRay
                                                                    bool visibleOnly, bool collidableOnly) {
     float bestDistance = std::numeric_limits<float>::max();
     bool bestIsFront = false;
+    bool bestIsTablet = false;
+    auto tabletIDs = qApp->getTabletIDs();
 
     QMutexLocker locker(&_mutex);
     RayToOverlayIntersectionResult result;
@@ -554,10 +556,11 @@ RayToOverlayIntersectionResult Overlays::findRayIntersectionVector(const PickRay
             if (thisOverlay->findRayIntersectionExtraInfo(ray.origin, ray.direction, thisDistance,
                                                           thisFace, thisSurfaceNormal, thisExtraInfo, precisionPicking)) {
                 bool isDrawInFront = thisOverlay->getDrawInFront();
-                if ((bestIsFront && isDrawInFront && thisDistance < bestDistance)
-                    || (!bestIsFront && (isDrawInFront || thisDistance < bestDistance))) {
-
+                bool isTablet = tabletIDs.contains(thisID);
+                if (isDrawInFront && !bestIsFront && !bestIsTablet
+                        || (isTablet || isDrawInFront || !bestIsFront) && thisDistance < bestDistance) {
                     bestIsFront = isDrawInFront;
+                    bestIsTablet = isTablet;
                     bestDistance = thisDistance;
                     result.intersects = true;
                     result.distance = thisDistance;
diff --git a/interface/src/ui/overlays/Overlays.h b/interface/src/ui/overlays/Overlays.h
index 21b9e93648..4c87a338d5 100644
--- a/interface/src/ui/overlays/Overlays.h
+++ b/interface/src/ui/overlays/Overlays.h
@@ -383,7 +383,11 @@ public slots:
     OverlayPropertyResult getOverlaysProperties(const QVariant& overlaysProperties);
 
     /**jsdoc
-     * Find the closest 3D overlay intersected by a {@link PickRay}.
+     *  Find the closest 3D overlay intersected by a {@link PickRay}. Overlays with their <code>drawInFront</code> property set  
+     * to <code>true</code> have priority over overlays that don't, except that tablet overlays have priority over any  
+     * <code>drawInFront</code> overlays behind them. I.e., if a <code>drawInFront</code> overlay is behind one that isn't  
+     * <code>drawInFront</code>, the <code>drawInFront</code> overlay is returned, but if a tablet overlay is in front of a  
+     * <code>drawInFront</code> overlay, the tablet overlay is returned.
      * @function Overlays.findRayIntersection
      * @param {PickRay} pickRay - The PickRay to use for finding overlays.
      * @param {boolean} [precisionPicking=false] - <em>Unused</em>; exists to match Entity API.