Pass frame time delta through to the logic component frame update

Allows for smoother animations in logic components.

Change-Id: I2aad5055465b3afbac415e21a356e216701551ef
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

7 files changed, 24 insertions, 11 deletions

diff --git a/src/logic/executor.cpp b/src/logic/executor.cpp
index 95de46f0e..e34299fed 100644
--- a/src/logic/executor.cpp
+++ b/src/logic/executor.cpp
@@ -71,7 +71,8 @@ void Executor::enqueueLogicFrameUpdates(const QVector<Qt3DCore::QNodeId> &nodeId
 bool Executor::event(QEvent *e)
 {
     if (e->type() == QEvent::User) {
-        processLogicFrameUpdates();
+        FrameUpdateEvent *ev = static_cast<FrameUpdateEvent *>(e);
+        processLogicFrameUpdates(ev->deltaTime());
         e->setAccepted(true);
         return true;
     }
@@ -83,7 +84,7 @@ bool Executor::event(QEvent *e)
 
    Called from context of main thread
 */
-void Executor::processLogicFrameUpdates()
+void Executor::processLogicFrameUpdates(float dt)
 {
     Q_ASSERT(m_scene);
     Q_ASSERT(m_semaphore);
@@ -91,7 +92,7 @@ void Executor::processLogicFrameUpdates()
     foreach (QNode *node, nodes) {
         QLogicComponent *logicComponent = qobject_cast<QLogicComponent *>(node);
         if (logicComponent)
-            logicComponent->onFrameUpdate();
+            logicComponent->onFrameUpdate(dt);
     }
 
     // Release the semaphore so the calling Manager can continue
diff --git a/src/logic/executor_p.h b/src/logic/executor_p.h
index ec48a3e38..79effddb3 100644
--- a/src/logic/executor_p.h
+++ b/src/logic/executor_p.h
@@ -66,9 +66,15 @@ namespace Logic {
 class FrameUpdateEvent : public QEvent
 {
 public:
-    FrameUpdateEvent()
+    FrameUpdateEvent(float dt)
         : QEvent(QEvent::User)
+        , m_dt(dt)
     {}
+
+    float deltaTime() const { return m_dt; }
+
+private:
+    float m_dt;
 };
 
 class Executor : public QObject
@@ -86,7 +92,7 @@ public Q_SLOTS:
 
 protected:
     bool event(QEvent *e);
-    void processLogicFrameUpdates();
+    void processLogicFrameUpdates(float dt);
 
 private:
     QVector<Qt3DCore::QNodeId> m_nodeIds;
diff --git a/src/logic/manager.cpp b/src/logic/manager.cpp
index e6ab804f8..6ef0f9364 100644
--- a/src/logic/manager.cpp
+++ b/src/logic/manager.cpp
@@ -51,6 +51,7 @@ namespace Logic {
 Manager::Manager()
     : m_logicHandlerManager(new HandlerManager)
     , m_semaphore(1)
+    , m_dt(0.0f)
 {
     m_semaphore.acquire();
 }
@@ -94,7 +95,7 @@ void Manager::triggerLogicFrameUpdates()
     // logic component and then wait until done. The Executor will
     // release the semaphore when it has completed its work.
     m_executor->enqueueLogicFrameUpdates(m_logicComponentIds);
-    qApp->postEvent(m_executor, new FrameUpdateEvent);
+    qApp->postEvent(m_executor, new FrameUpdateEvent(m_dt));
     m_semaphore.acquire();
 }
 
diff --git a/src/logic/manager_p.h b/src/logic/manager_p.h
index 8d62a20c2..25b9d958b 100644
--- a/src/logic/manager_p.h
+++ b/src/logic/manager_p.h
@@ -82,6 +82,8 @@ public:
 
     void triggerLogicFrameUpdates();
 
+    void setDeltaTime(float dt) { m_dt = dt; }
+
 private:
     QScopedPointer<HandlerManager> m_logicHandlerManager;
     QVector<HHandler> m_logicHandlers;
@@ -89,6 +91,7 @@ private:
     QLogicAspect *m_logicAspect;
     Executor *m_executor;
     QSemaphore m_semaphore;
+    float m_dt;
 };
 
 } // namespace Logic
diff --git a/src/logic/qlogicaspect.cpp b/src/logic/qlogicaspect.cpp
index a34dffe89..04f509ab1 100644
--- a/src/logic/qlogicaspect.cpp
+++ b/src/logic/qlogicaspect.cpp
@@ -94,8 +94,10 @@ void QLogicAspect::registerBackendTypes()
 QVector<QAspectJobPtr> QLogicAspect::jobsToExecute(qint64 time)
 {
     Q_D(QLogicAspect);
+    const qint64 deltaTime = time - d->m_time;
+    const float dt = static_cast<const float>(deltaTime) / 1.0e9;
+    d->m_manager->setDeltaTime(dt);
     d->m_time = time;
-    // TODO: Ensure arbiter and postman are setup prior to invoking QAspectManager::initialize()
 
     // Create jobs that will get exectued by the threadpool
     QVector<QAspectJobPtr> jobs;
diff --git a/src/logic/qlogiccomponent.cpp b/src/logic/qlogiccomponent.cpp
index 2b99f0e14..878bc24d7 100644
--- a/src/logic/qlogiccomponent.cpp
+++ b/src/logic/qlogiccomponent.cpp
@@ -99,11 +99,11 @@ QLogicComponent::~QLogicComponent()
     This virtual function will be called in a synchronous manner once each frame by
     the Logic aspect.
 */
-void QLogicComponent::onFrameUpdate()
+void QLogicComponent::onFrameUpdate(float dt)
 {
     // Emit signal so that QML instances get the onFrameUpdate() signal
     // handler called
-    emit frameUpdate();
+    emit frameUpdate(dt);
 }
 
 } // namespace Qt3DLogic
diff --git a/src/logic/qlogiccomponent.h b/src/logic/qlogiccomponent.h
index 500b1d85b..68d0bf69a 100644
--- a/src/logic/qlogiccomponent.h
+++ b/src/logic/qlogiccomponent.h
@@ -63,13 +63,13 @@ protected:
     QLogicComponent(QLogicComponentPrivate &dd, QNode *parent = 0);
 
 Q_SIGNALS:
-    void frameUpdate();
+    void frameUpdate(float dt);
 
 private:
     Q_DECLARE_PRIVATE(QLogicComponent)
     QT3D_CLONEABLE(QLogicComponent)
 
-    virtual void onFrameUpdate();
+    virtual void onFrameUpdate(float dt);
 
     friend class Logic::Executor;
 };