Added touch screen pinch zoom and rotate

Added pinch zoom on the glwidget and rotate around center on object axis on pinch roatate. May want to add a roate lock on the pinch gesture to stop roation of object by mistake.

src/gl3widget.cpp

@@ -9,6 +9,8 @@
 #include <QMouseEvent>
 #include <QWheelEvent>
 #include <QVector4D>
+#include <QGesture>
+
 #include "rowmans.h"
 #include "globals.h"
 
@@ -38,6 +40,14 @@ GlWidget::GlWidget(QWidget *parent)
     StereoSeparation = static_cast<float>(.04);
     setFocusPolicy(Qt::NoFocus);
     DefaultClipAngle = MainWin->ui->ClipAngle->value() / 10;
+
+    // Capture the following touch screen gestures
+    QList<Qt::GestureType> gestures;
+    gestures << Qt::PanGesture;
+    gestures << Qt::PinchGesture;
+    gestures << Qt::SwipeGesture;
+    grabGestures(gestures);
+
     //setAutoBufferSwap(true);
 
     //qDebug() << "Done init widget";
@@ -191,11 +201,15 @@ void GlWidget::resizeGL(int width, int height)
     {
         height = 1;
     }
+
     // Scale all x and y by the application screen ratio
     xdim = static_cast<int>(static_cast<double>(width) * applicationScaleX);
     ydim = static_cast<int>(static_cast<double>(height) * applicationScaleY);
+
     DoPMatrix(xdim, ydim);
+
     glfunctions->glViewport(0, 0, xdim, ydim);
+
     update();
 }
 
@@ -208,6 +222,7 @@ void GlWidget::DoPMatrix(int width, int height)
 {
     float asp = static_cast<float>(width) / static_cast<float>(height);
     float fudge = static_cast<float>(1300) / static_cast<float>(width);
+
     pMatrix.setToIdentity();
     if (MainWin->ui->actionOrthographic_View->isChecked())
         pMatrix.ortho((0 - ClipAngle / (10 * fudge)), ClipAngle / (10 * fudge), (0 - ClipAngle / (10 * fudge)) / asp, ClipAngle / (10 * fudge) / asp, ClipStart, ClipDepth);
@@ -1107,3 +1122,106 @@ void GlWidget::NewDefault()
         Ztrans = 0;
     }
 }
+
+/**
+ * @brief GlWidget::event
+ * @param event
+ * @return
+ */
+bool GlWidget::event(QEvent *event)
+{
+    if (event->type() == QEvent::Gesture)
+        return gestureEvent(static_cast<QGestureEvent *>(event));
+    return QWidget::event(event);
+}
+
+/**
+ * @brief GlWidget::grabGestures
+ * @param gestures
+ */
+void GlWidget::grabGestures(const QList<Qt::GestureType> &gestures)
+{
+    foreach (Qt::GestureType gesture, gestures)
+        grabGesture(gesture);
+}
+
+/**
+ * @brief GlWidget::gestureEvent
+ * @param event
+ * @return
+ */
+bool GlWidget::gestureEvent(QGestureEvent *event)
+{
+    //qDebug() << "gestureEvent():" << event;
+
+    /*
+    if (QGesture *swipe = event->gesture(Qt::SwipeGesture))
+    {
+        swipeTriggered(static_cast<QSwipeGesture *>(swipe));
+    }
+    else if (QGesture *pan = event->gesture(Qt::PanGesture))
+    {
+        panTriggered(static_cast<QPanGesture *>(pan));
+    }
+    */
+
+    if (QGesture *pinch = event->gesture(Qt::PinchGesture))
+    {
+        //qDebug() << "Pinch detected...";
+        pinchTriggered(static_cast<QPinchGesture *>(pinch));
+    }
+    return true;
+}
+
+/**
+ * @brief GlWidget::pinchTriggered
+ * @param gesture
+ */
+void GlWidget::pinchTriggered(QPinchGesture *gesture)
+{
+    QPinchGesture::ChangeFlags changeFlags = gesture->changeFlags();
+    double currentStepScaleFactor = 0;
+
+    if (changeFlags & QPinchGesture::RotationAngleChanged)
+    {
+        double rotationDelta = gesture->lastRotationAngle() - gesture->rotationAngle();
+        Rotate(rotationDelta);
+        update();
+
+        //qDebug() << "pinchTriggered(): rotate by" << rotationDelta;
+    }
+
+    if (changeFlags & QPinchGesture::ScaleFactorChanged)
+    {
+        currentStepScaleFactor = gesture->totalScaleFactor();
+        int currentClipAngle = MainWin->ui->ClipAngle->value();
+        int maximumClipAngleAllowed = MainWin->ui->ClipAngle->maximum();
+        int minimumClipAngleAllowed = MainWin->ui->ClipAngle->minimum();
+        int newClipAngle = currentClipAngle;
+
+        if (currentStepScaleFactor > 0.0)
+        {
+            // Zoom in
+            newClipAngle = static_cast<int>(static_cast<double>(currentClipAngle) * (1 + ((currentStepScaleFactor - 1) / 20)));
+            if (newClipAngle > maximumClipAngleAllowed) newClipAngle = maximumClipAngleAllowed;
+            MainWin->ui->ClipAngle->setValue(newClipAngle);
+        }
+        else if (currentStepScaleFactor < 0.0)
+        {
+            // Zoom Out
+            newClipAngle = static_cast<int>(static_cast<double>(currentClipAngle) * (currentStepScaleFactor / 20));
+            if (newClipAngle < minimumClipAngleAllowed) newClipAngle = minimumClipAngleAllowed;
+            MainWin->ui->ClipAngle->setValue(newClipAngle);
+        }
+        SetClip(MainWin->ui->ClipStart->value(), MainWin->ui->ClipDepth->value(), MainWin->ui->ClipAngle->value());
+        update();
+
+        //qDebug() << "pinchTriggered(): zoom by" << gesture->scaleFactor() << "->" << currentStepScaleFactor << " Current Clip = " << currentClipAngle << " New Clip = " << newClipAngle;
+    }
+
+    if (gesture->state() == Qt::GestureFinished)
+    {
+        update();
+    }
+
+}

src/gl3widget.h

@@ -5,6 +5,7 @@
 #include <QOpenGLShaderProgram>
 #include <QOpenGLBuffer>
 #include <QOpenGLFunctions>
+#include <QGestureEvent>
 
 #include "globals.h"
 
@@ -19,19 +20,19 @@ class GlWidget : public QOpenGLWidget
 public:
     GlWidget(QWidget *parent);
     ~GlWidget();
+    void grabGestures(const QList<Qt::GestureType> &gestures);
 
-    //Application specific stuff
-
-    QOpenGLFunctions *glfunctions;
     float ClipStart;
     float ClipDepth;
     float ClipAngle;
     float DefaultClipAngle;
-    int LastMouseXpos;
-    int LastMouseYpos;
-    int xdim, ydim;
     float campos;
     float StereoSeparation;
+    int LastMouseXpos;
+    int LastMouseYpos;
+    int xdim;
+    int ydim;
+    QOpenGLFunctions *glfunctions;
 
     bool CanISee(int index);
     void SetClip(int Start, int Depth, int Angle);
@@ -40,12 +41,10 @@ class GlWidget : public QOpenGLWidget
     void MoveAway(double dist);
     void DrawObjects(bool rightview, bool halfsize);
     void SetStereoSeparation(float s);
-    //void setQuadStereo(bool st);
     void YRotate(float angle);
     void ZRotate(float angle);
     void XRotate(float angle);
     void Translate(float x, float y, float z);
-
     void Resize(float value);
     void ResetSize();
     void ResetToDefault();
@@ -54,18 +53,26 @@ class GlWidget : public QOpenGLWidget
     void DrawLine(QMatrix4x4 vMatrix, QVector3D lPosition, float pos, bool major, bool horizontal);
     void RenderCharacter(GLfloat x, GLfloat y, GLfloat z, int charactercode, QMatrix4x4 vMatrix, QColor Colour);
     void RenderNumber(GLfloat x, GLfloat y, GLfloat z, float number, int decimalplaces, bool mm, bool major, QMatrix4x4 vMatrix);
+
 protected:
+    // Overrides
+    bool event(QEvent *event);
     void initializeGL();
     void resizeGL(int width, int height);
     void paintGL();
     void mouseMoveEvent(QMouseEvent *event);
-    QOpenGLBuffer VBOline, occBuffer;
-    int numOccVertices;
 
+    int numOccVertices;
+    GLfloat CharacterWidths[13]; //widths of these characters
+    GLfloat CharacterLineCounts[13]; //widths of these characters
     QOpenGLBuffer VBOcharacters[13]; //0-9 are digits 0-9, 10 is -, 11 is ., 12 is m
-    GLfloat CharacterWidths[13], CharacterLineCounts[13]; //widths of these characters
+    QOpenGLBuffer VBOline;
+    QOpenGLBuffer occBuffer;
 
 private:
+    bool gestureEvent(QGestureEvent *event);
+    void pinchTriggered(QPinchGesture *gesture);
+
     QMatrix4x4 pMatrix;
     QMatrix4x4 ScaleMatrix; //Manipulations to scale ball
     QOpenGLShaderProgram lightingShaderProgram;