rework AnimationDriver

Author: rectalogic

com/rectalogic/RenderWindow/animation.h

@@ -9,20 +9,18 @@ const qint32 FRAMERATE_MILLIS = 40;
 
 class AnimationDriver : public QAnimationDriver {
 public:
-    AnimationDriver(qint32 stepMillis = FRAMERATE_MILLIS, QObject* parent = nullptr)
+    AnimationDriver(QObject* parent = nullptr)
         : QAnimationDriver(parent)
-        , m_step(stepMillis)
     {
     }
 
-    void setStep(qint32 millis)
+    void setElapsed(qint64 elapsedMillis)
     {
-        m_step = millis;
+        m_elapsed = elapsedMillis;
     }
 
     void advance() override
     {
-        m_elapsed += m_step;
         advanceAnimation();
     }
 
@@ -32,6 +30,6 @@ class AnimationDriver : public QAnimationDriver {
     }
 
 private:
-    qint32 m_step;
+    qint32 m_increment = 0;
     qint64 m_elapsed = 0;
 };

com/rectalogic/RenderWindow/render_window.cpp

@@ -54,16 +54,15 @@ void RenderWindow::componentComplete()
     contentItem()->setSize(size());
 }
 
-QByteArray RenderWindow::render(qint32 durationMillis)
+QByteArray RenderWindow::render(qint64 elapsedMillis)
 {
     if (!m_isValid) {
         emit qmlEngine(this)->exit(1);
         return QByteArray();
     }
-    if (durationMillis > 0) {
-        m_animationDriver->setStep(durationMillis);
-        m_animationDriver->advance();
-    }
+
+    m_animationDriver->setElapsed(elapsedMillis);
+    m_animationDriver->advance();
 
     QByteArray data = m_renderControl->renderFrame();
     if (data.isNull()) {

com/rectalogic/RenderWindow/render_window.h

@@ -33,7 +33,7 @@ class RenderWindow : public QQuickWindow, public QQmlParserStatus {
     RenderWindow& operator=(RenderWindow&&) = delete;
     ~RenderWindow() override;
 
-    Q_INVOKABLE QByteArray render(qint32 durationMillis = 0);
+    Q_INVOKABLE QByteArray render(qint64 elapsedMillis);
 
 protected:
     void classBegin() override { }