Allow resetting with existing array for surface

Improves performance when doing stuff like resetting image data.

Task-number: QTRD-2335
Change-Id: I9e8ce49fd520b67125305a7614afc550b2244169
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

2 files changed, 42 insertions, 9 deletions

diff --git a/examples/surfacechart/chartmodifier.cpp b/examples/surfacechart/chartmodifier.cpp
index 67c523ef..1d791f89 100644
--- a/examples/surfacechart/chartmodifier.cpp
+++ b/examples/surfacechart/chartmodifier.cpp
@@ -26,6 +26,8 @@
 
 QT_DATAVISUALIZATION_USE_NAMESPACE
 
+//#define JITTER_PLANE
+
 ChartModifier::ChartModifier(Q3DSurface *chart)
     : m_chart(chart),
       m_gridSliderX(0),
@@ -41,13 +43,16 @@ ChartModifier::ChartModifier(Q3DSurface *chart)
       m_rangeX(16.0),
       m_rangeZ(16.0),
       m_minX(-8.0),
-      m_minZ(-8.0)
+      m_minZ(-8.0),
+      m_planeArray(0)
 {
     m_chart->setAxisX(new Q3DValueAxis);
     m_chart->setAxisY(new Q3DValueAxis);
     m_chart->setAxisZ(new Q3DValueAxis);
     m_chart->axisX()->setRange(m_minX, m_minX + m_rangeX);
     m_chart->axisZ()->setRange(m_minZ, m_minZ + m_rangeZ);
+
+    connect(&m_timer, &QTimer::timeout, this, &ChartModifier::timeout);
 }
 
 ChartModifier::~ChartModifier()
@@ -105,24 +110,33 @@ void ChartModifier::togglePlane(bool enable)
     qDebug() << "ChartModifier::togglePlane " << enable;
 
     if (enable) {
-        QSurfaceDataArray *dataArray = new QSurfaceDataArray;
+        m_planeArray = new QSurfaceDataArray;
+
+#ifdef JITTER_PLANE
+        m_timer.start(0);
+#endif
+        m_chart->axisY()->setRange(0.0, 1.0);
+        m_chart->axisX()->setLabelFormat("%.2f");
+        m_chart->axisZ()->setLabelFormat("%.2f");
+
         qreal y = 1.0 / (qreal(m_zCount - 1) + qreal(m_xCount - 1));
-        dataArray->reserve(m_zCount);
+        m_planeArray->reserve(m_zCount);
         for (int i = 0; i < m_zCount; i++) {
             QSurfaceDataRow *newRow = new QSurfaceDataRow(m_xCount);
             for (int j = 0; j < m_xCount; j++)
                 (*newRow)[j] = (i + j) * y;
-            *dataArray << newRow;
+            *m_planeArray << newRow;
         }
 
-        m_chart->axisY()->setRange(0.0, 1.0);
-        m_chart->axisX()->setLabelFormat("%.2f");
-        m_chart->axisZ()->setLabelFormat("%.2f");
-
-        resetArrayAndSliders(dataArray, -10.0, 10.0, -10.0, 20.0);
+        resetArrayAndSliders(m_planeArray, -10.0, 10.0, -10.0, 20.0);
 
         m_activeSample = ChartModifier::Plane;
     }
+#ifdef JITTER_PLANE
+    else {
+        m_timer.stop();
+    }
+#endif
 }
 
 void ChartModifier::setHeightMapData(bool enable)
@@ -247,6 +261,21 @@ void ChartModifier::changeTheme(int theme)
     m_chart->setTheme((QDataVis::ColorTheme)theme);
 }
 
+void ChartModifier::timeout()
+{
+    int rows = m_planeArray->size();
+    int columns = m_planeArray->at(0)->size();
+
+    // Induce minor random jitter to the existing plane array
+    for (int i = 0; i < rows; i++) {
+        for (int j = 0; j < columns; j++)
+            (*m_planeArray->at(i))[j] = m_planeArray->at(i)->at(j) * ((qreal((rand() % 10) + 4) / 1000.0) + 0.99) + 0.001;
+    }
+
+    // Reset same array to make it redraw
+    m_chart->activeDataProxy()->resetArray(m_planeArray);
+}
+
 void ChartModifier::resetArrayAndSliders(QSurfaceDataArray *array, qreal minZ, qreal maxZ, qreal minX, qreal maxX)
 {
     m_axisMinSliderX->setValue(minX);
diff --git a/examples/surfacechart/chartmodifier.h b/examples/surfacechart/chartmodifier.h
index 61d97cb0..ab27d269 100644
--- a/examples/surfacechart/chartmodifier.h
+++ b/examples/surfacechart/chartmodifier.h
@@ -22,6 +22,7 @@
 #include <QtDataVisualization/Q3DSurface>
 #include <QtDataVisualization/QSurfaceDataProxy>
 #include <QSlider>
+#include <QTimer>
 
 using namespace QtDataVisualization;
 
@@ -65,6 +66,7 @@ public slots:
     void changeShadowQuality(int quality);
     void changeTheme(int theme);
     void changeSelectionMode(int mode);
+    void timeout();
 
 private:
     void resetArrayAndSliders(QSurfaceDataArray *array, qreal minZ, qreal maxZ, qreal minX,
@@ -86,6 +88,8 @@ private:
     qreal m_rangeZ;
     qreal m_minX;
     qreal m_minZ;
+    QTimer m_timer;
+    QSurfaceDataArray *m_planeArray;
 };
 
 #endif // CHARTMODIFIER_H