From ff07e476266cd5038982dde7f6f1dff1612808b4 Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zach@highfidelity.io>
Date: Mon, 14 Mar 2016 17:49:37 -0700
Subject: [PATCH 1/2] Make procedural dirty marker atomic

---
 libraries/procedural/src/procedural/Procedural.cpp | 8 ++++----
 libraries/procedural/src/procedural/Procedural.h   | 4 +++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/libraries/procedural/src/procedural/Procedural.cpp b/libraries/procedural/src/procedural/Procedural.cpp
index 9b8d0fe294..071b07b48a 100644
--- a/libraries/procedural/src/procedural/Procedural.cpp
+++ b/libraries/procedural/src/procedural/Procedural.cpp
@@ -62,13 +62,13 @@ QJsonValue Procedural::getProceduralData(const QString& proceduralJson) {
     return doc.object()[PROCEDURAL_USER_DATA_KEY];
 }
 
-Procedural::Procedural() {
-    _state = std::make_shared<gpu::State>();
+Procedural::Procedural() : _state { std::make_shared<gpu::State>() } {
+    _proceduralDataDirty = false;
 }
 
-Procedural::Procedural(const QString& userDataJson) {
+Procedural::Procedural(const QString& userDataJson) : Procedural() {
     parse(userDataJson);
-    _state = std::make_shared<gpu::State>();
+    _proceduralDataDirty = true;
 }
 
 void Procedural::parse(const QString& userDataJson) {
diff --git a/libraries/procedural/src/procedural/Procedural.h b/libraries/procedural/src/procedural/Procedural.h
index 0e55f52f5a..f928d0e594 100644
--- a/libraries/procedural/src/procedural/Procedural.h
+++ b/libraries/procedural/src/procedural/Procedural.h
@@ -10,6 +10,8 @@
 #ifndef hifi_RenderableProcedrualItem_h
 #define hifi_RenderableProcedrualItem_h
 
+#include <atomic>
+
 #include <QtCore/qglobal.h>
 #include <QtCore/QString>
 #include <QtCore/QUrl>
@@ -74,7 +76,7 @@ protected:
     NetworkShaderPointer _networkShader;
     QJsonObject _parsedUniforms;
     QJsonArray _parsedChannels;
-    bool _proceduralDataDirty { true };
+    std::atomic_bool _proceduralDataDirty;
     bool _shaderDirty { true };
     bool _uniformsDirty { true };
     bool _channelsDirty { true };

From 1a8cca3dcca0f4e59b5d25429b9b9a03962b1c30 Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zmp@umich.edu>
Date: Tue, 15 Mar 2016 10:51:55 -0700
Subject: [PATCH 2/2] Clarify use of procedural's dirty atomic flag

---
 libraries/procedural/src/procedural/Procedural.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libraries/procedural/src/procedural/Procedural.cpp b/libraries/procedural/src/procedural/Procedural.cpp
index 071b07b48a..d3aed38198 100644
--- a/libraries/procedural/src/procedural/Procedural.cpp
+++ b/libraries/procedural/src/procedural/Procedural.cpp
@@ -77,6 +77,9 @@ void Procedural::parse(const QString& userDataJson) {
     // This will be called by Procedural::ready
     std::lock_guard<std::mutex> lock(_proceduralDataMutex);
     _proceduralData = proceduralData.toObject();
+
+    // Mark as dirty after modifying _proceduralData, but before releasing lock
+    // to avoid setting it after parsing has begun
     _proceduralDataDirty = true;
 }
 
@@ -166,9 +169,13 @@ void Procedural::parse(const QJsonObject& proceduralData) {
 
 bool Procedural::ready() {
     // Load any changes to the procedural
+    // Check for changes atomically, in case they are currently being made
     if (_proceduralDataDirty) {
         std::lock_guard<std::mutex> lock(_proceduralDataMutex);
         parse(_proceduralData);
+
+        // Reset dirty flag after reading _proceduralData, but before releasing lock
+        // to avoid resetting it after more data is set
         _proceduralDataDirty = false;
     }