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.


#include <QGLViewer/qglviewer.h>

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

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

  virtual QString helpString() const;

  bool wireframe_, flatShading_;


#include "keyboardAndMouse.h"

#include <QCursor>
#include <QKeyEvent>
#include <QMap>
#include <QMenu>
#include <QMouseEvent>

#include <math.h>

using namespace std;

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

  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);

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

  //       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::Key_Z, Qt::NoModifier, Qt::LeftButton, CAMERA, ZOOM);

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

  setMouseBinding(Qt::ControlModifier | Qt::ShiftModifier, Qt::RightButton,
  setWheelBinding(Qt::AltModifier, CAMERA, MOVE_FORWARD);
  setMouseBinding(Qt::AltModifier, Qt::LeftButton, CAMERA, TRANSLATE);

  // 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().

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

void Viewer::keyPressEvent(QKeyEvent *e) {
  // Get event modifiers key
  const Qt::KeyboardModifiers modifiers = e->modifiers();

  // 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);
      glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    handled = true;
  } else if ((e->key() == Qt::Key_F) && (modifiers == Qt::NoButton)) {
    flatShading_ = !flatShading_;
    if (flatShading_)
    handled = true;
  // ... and so on with other else/if blocks.

  if (!handled)

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

void Viewer::mousePressEvent(QMouseEvent *e) {
  if ((e->button() == Qt::RightButton) && (e->modifiers() == Qt::NoButton)) {
    QMenu menu(this);
    menu.addAction("Camera positions");
    QMap<QAction *, int> menuMap;

    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);
          text = "Path " + QString::number(i);

        menuMap[menu.addAction(text)] = i;

    if (!atLeastOne) {
      menu.addAction("No position defined");
      menu.addAction("Use to Alt+Fx to define one");

    QAction *action = menu.exec(e->globalPos());

    if (atLeastOne && action)
  } else

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 "
  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;


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

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

  Viewer viewer;


  return application.exec();

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