libQGLViewer keyboardAndMouse example

Home Download Gallery Documentation Developer

# The keyboardAndMouse example

Shows how to customize your keyboard and mouse bindings.

Use `setShortcut()` to change standard action bindings (axis, grid or fps display, exit...).

Use `setMouseBinding()` and `setWheelBinding()` to change standard action mouse bindings (camera rotation, translation, object selection...).

If you want to define new keyboard shortcuts, overload `keyPressEvent()` and bind your own new actions. Use setKeyDescription() to add your shortcuts in the help window.

To define new mouse actions, overload `mouse(Press|Move|Release)Event`. See the `mouseMoveEvent()` documentation for an example. Overload `setMouseBindingDescription()` to update the help window binding tab.

## keyboardAndMouse.h

    #include <QGLViewer/qglviewer.h>

    class Viewer : public QGLViewer
    {
    public:
      Viewer() : wireframe_(false), flatShading_(false) {};

    protected :
      virtual void draw();
      virtual void init();
      virtual void keyPressEvent(QKeyEvent *e);
      virtual void mousePressEvent(QMouseEvent* e);

      virtual QString helpString() const;

    private :
      bool wireframe_, flatShading_;
    };

## keyboardAndMouse.cpp

    #include "keyboardAndMouse.h"
    #if QT_VERSION < 0x040000
    # include <qpopupmenu.h>
    #else
    # include <QMenu>
    # include <QKeyEvent>
    # include <QMouseEvent>
    #endif
    #include <qcursor.h>
    #include <qmap.h>
    #include <math.h>

    using namespace std;

    // Draws a spiral
    void Viewer::draw()
    {
      const float nbSteps = 80.0;

      glBegin(GL_QUAD_STRIP);
      for (float i=0; i<nbSteps; ++i)
        {
          float ratio = i/nbSteps;
          float angle = 21.0*ratio;
          float c = cos(angle);
          float s = sin(angle);
          float r1 = 1.0 - 0.8*ratio;
          float r2 = 0.8 - 0.8*ratio;
          float alt = ratio - 0.5;
          const float nor = .5;
          const float up = sqrt(1.0-nor*nor);
          glColor3f(fabs(c), 0.2f, fabs(s));
          glNormal3f(nor*c, up, nor*s);
          glVertex3f(r1*c, alt, r1*s);
          glVertex3f(r2*c, alt+0.05, r2*s);
        }
      glEnd();
    }

    void Viewer::init()
    {
      // Restore previous viewer state.
      restoreStateFromFile();

      /////////////////////////////////////////////////////
      //       Keyboard shortcut customization           //
      //      Changes standard action key bindings       //
      /////////////////////////////////////////////////////

      // Define 'Control+Q' as the new exit shortcut (default was 'Escape')
      setShortcut(EXIT_VIEWER, Qt::CTRL+Qt::Key_Q);

      // Set 'Control+F' as the FPS toggle state key.
      setShortcut(DISPLAY_FPS, Qt::CTRL+Qt::Key_F);

      // Disable draw grid toggle shortcut (default was 'G')
      setShortcut(DRAW_GRID, 0);

      // Add custom key description (see keyPressEvent).
      setKeyDescription(Qt::Key_W, "Toggles wire frame display");
      setKeyDescription(Qt::Key_F, "Toggles flat shading display");

      /////////////////////////////////////////////////////
      //         Mouse bindings customization            //
      //     Changes standard action mouse bindings      //
      /////////////////////////////////////////////////////

      // Left and right buttons together make a camera zoom : emulates a mouse third button if needed.
      setMouseBinding(Qt::NoModifier, Qt::LeftButton | Qt::RightButton, CAMERA, ZOOM);

      // Disable previous TRANSLATE mouse binding (and remove it from help mouse tab).
      setMouseBinding(Qt::NoModifier, Qt::RightButton, NO_CLICK_ACTION);

    #if QT_VERSION < 0x040000
      // Alt+left button translates the camera (since right button will popup a menu).
      setMouseBinding(Qt::AltButton, Qt::LeftButton, CAMERA, TRANSLATE);
      // Define Control+Shift+Right button as selection shortcut
      setMouseBinding(Qt::ControlButton | Qt::ShiftButton, Qt::RightButton, SELECT);
      // Alt + mouse wheel MOVE_FORWARD the camera.
      setWheelBinding(Qt::AltButton, CAMERA, MOVE_FORWARD);
    #else
      setMouseBinding(Qt::ControlModifier | Qt::ShiftModifier, Qt::RightButton, SELECT);
      setWheelBinding(Qt::AltModifier, CAMERA, MOVE_FORWARD);
      setMouseBinding(Qt::AltModifier, Qt::LeftButton, CAMERA, TRANSLATE);
    #endif

      // Add custom mouse bindings description (see mousePressEvent())
      setMouseBindingDescription(Qt::NoModifier, Qt::RightButton, "Opens a camera path context menu");

      // Display the help window. The help window tabs are automatically updated when you define new
      // standard key or mouse bindings (as is done above). Custom bindings descriptions are added using
      // setKeyDescription() and setMouseBindingDescription().
      help();
    }

    ///////////////////////////////////////////////
    //      Define new key bindings : F & W      //
    ///////////////////////////////////////////////

    void Viewer::keyPressEvent(QKeyEvent *e)
    {
      // Get event modifiers key
    #if QT_VERSION < 0x040000
      // Bug in Qt : use 0x0f00 instead of Qt::KeyButtonMask with Qt versions < 3.1
      const Qt::ButtonState modifiers = (Qt::ButtonState)(e->state() & Qt::KeyButtonMask);
    #else
      const Qt::KeyboardModifiers modifiers = e->modifiers();
    #endif

      // A simple switch on e->key() is not sufficient if we want to take state key into account.
      // With a switch, it would have been impossible to separate 'F' from 'CTRL+F'.
      // That's why we use imbricated if...else and a "handled" boolean.
      bool handled = false;
      if ((e->key()==Qt::Key_W) && (modifiers==Qt::NoButton))
        {
          wireframe_ = !wireframe_;
          if (wireframe_)
    	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
          else
    	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
          handled = true;
          updateGL();
        }
      else
        if ((e->key()==Qt::Key_F) && (modifiers==Qt::NoButton))
          {
    	flatShading_ = !flatShading_;
    	if (flatShading_)
    	  glShadeModel(GL_FLAT);
    	else
    	  glShadeModel(GL_SMOOTH);
    	handled = true;
    	updateGL();
          }
      // ... and so on with other else/if blocks.

      if (!handled)
        QGLViewer::keyPressEvent(e);
    }

    ///////////////////////////////////////////////////////////
    //             Define new mouse bindings                 //
    //   A camera viewpoint menu binded on right button      //
    ///////////////////////////////////////////////////////////

    void Viewer::mousePressEvent(QMouseEvent* e)
    {
    #if QT_VERSION < 0x040000
      if ((e->button() == Qt::RightButton) && (e->state() == Qt::NoButton))
    #else
      if ((e->button() == Qt::RightButton) && (e->modifiers() == Qt::NoButton))
    #endif
        {
    #if QT_VERSION < 0x040000
          QPopupMenu menu( this );
          menu.insertItem("Camera positions");
          menu.insertSeparator();
          QMap<int, int> menuMap;
    #else
          QMenu menu( this );
          menu.addAction("Camera positions");
          menu.addSeparator();
          QMap<QAction*, int> menuMap;
    #endif

          bool atLeastOne = false;
          // We only test the 20 first indexes. This is a limitation.
          for (unsigned short i=0; i<20; ++i)
    	if (camera()->keyFrameInterpolator(i))
    	  {
    	    atLeastOne = true;
    	    QString text;
    	    if (camera()->keyFrameInterpolator(i)->numberOfKeyFrames() == 1)
    	      text = "Position "+QString::number(i);
    	    else
    	      text = "Path "+QString::number(i);

    #if QT_VERSION < 0x040000
    	    menuMap[menu.insertItem(text)] = i;
    #else
    	    menuMap[menu.addAction(text)] = i;
    #endif
    	  }

          if (!atLeastOne)
    	{
    #if QT_VERSION < 0x040000
    	  menu.insertItem("No position defined");
    	  menu.insertItem("Use to Alt+Fx to define one");
    #else
    	  menu.addAction("No position defined");
    	  menu.addAction("Use to Alt+Fx to define one");
    #endif
    	}

    #if QT_VERSION < 0x040000
          menu.setMouseTracking(true);
          int select = menu.exec(e->globalPos());

          if (atLeastOne && select != -1)
    	camera()->playPath(menuMap[select]);
    #else
          QAction* action = menu.exec(e->globalPos());

          if (atLeastOne && action)
    	camera()->playPath(menuMap[action]);
    #endif
        }
      else
        QGLViewer::mousePressEvent(e);
    }

    QString Viewer::helpString() const
    {
      QString text("<h2>K e y b o a r d A n d M o u s e</h2>");
      text += "This example illustrates the mouse and key bindings customization.<br><br>";
      text += "Use <code>setShortcut()</code> to change standard action key bindings (display of axis, grid or fps, exit shortcut...).<br><br>";
      text += "Use <code>setMouseBinding()</code> and <code>setWheelBinding()</code> to change standard action mouse bindings ";
      text += "(camera rotation, translation, object selection...).<br><br>";
      text += "If you want to define <b>new</b> key or mouse actions, overload <code>keyPressEvent()</code> and/or ";
      text += "<code>mouse(Press|Move|Release)Event()</code> to define and bind your own new actions. ";
      text += "Use <code>setKeyDescription()</code> and <code>setMouseBindingDescription()</code> to add a description of your bindings in the help window.<br><br>";
      text += "In this example, we defined the <b>F</b> and <b>W</b> keys and the right mouse button opens a popup menu. ";
      text += "See the keyboard and mouse tabs in this help window for the complete bindings description.<br><br>";
      text += "By the way, exit shortcut has been binded to <b>Ctrl+Q</b>.";
      return text;
    }

## main.cpp

    #include "keyboardAndMouse.h"
    #include <qapplication.h>

    int main(int argc, char** argv)
    {
      QApplication application(argc,argv);

      Viewer viewer;

    #if QT_VERSION < 0x040000
      application.setMainWidget(&viewer);
    #else
      viewer.setWindowTitle("keyboardAndMouse");
    #endif

      viewer.show();

      return application.exec();
    }

Back to the examples main page.

Last modified on Thursday, December 19, 2013.