Add first person camera controller mode and make it the default

For most scenes this is what people want in preference to the free-look
mode. Keeping a consistent up vector is more natural for most people.

This is a temporary hack until we get the InputManager completed and
we have a proper abstraction for controllers. After all, who says the
inputs should control the camera. They should be able to control any
Entity with a Transform. This also requires the Transform refactoring
to be completed before we can tie both sides together.

Change-Id: If8f02c66febcdee31c13ee46b6651a0e923e8d09
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

4 files changed, 95 insertions, 9 deletions

diff --git a/src/core/core-components/qcamera.cpp b/src/core/core-components/qcamera.cpp
index 0746b408b..53d22f1e5 100644
--- a/src/core/core-components/qcamera.cpp
+++ b/src/core/core-components/qcamera.cpp
@@ -196,6 +196,11 @@ QQuaternion QCamera::rollRotation(float angle) const
     return QQuaternion::fromAxisAndAngle(viewVector, -angle);
 }
 
+QQuaternion QCamera::rotation(float angle, const QVector3D &axis) const
+{
+    return QQuaternion::fromAxisAndAngle(axis, angle);
+}
+
 void QCamera::tilt(float angle)
 {
     QQuaternion q = tiltRotation(angle);
@@ -208,6 +213,12 @@ void QCamera::pan(float angle)
     rotate(q);
 }
 
+void QCamera::pan(float angle, const QVector3D &axis)
+{
+    QQuaternion q = rotation(-angle, axis);
+    rotate(q);
+}
+
 void QCamera::roll(float angle)
 {
     QQuaternion q = rollRotation(-angle);
@@ -226,6 +237,12 @@ void QCamera::panAboutViewCenter(float angle)
     rotateAboutViewCenter(q);
 }
 
+void QCamera::panAboutViewCenter(float angle, const QVector3D &axis)
+{
+    QQuaternion q = rotation(angle, axis);
+    rotateAboutViewCenter(q);
+}
+
 void QCamera::rollAboutViewCenter(float angle)
 {
     QQuaternion q = rollRotation(angle);
diff --git a/src/core/core-components/qcamera.h b/src/core/core-components/qcamera.h
index 2b13e1f9d..305cae930 100644
--- a/src/core/core-components/qcamera.h
+++ b/src/core/core-components/qcamera.h
@@ -88,6 +88,7 @@ public:
     QQuaternion tiltRotation(float angle) const;
     QQuaternion panRotation(float angle) const;
     QQuaternion rollRotation(float angle) const;
+    QQuaternion rotation(float angle, const QVector3D &axis) const;
 
     // Translate relative to camera orientation axes
     Q_INVOKABLE void translate(const QVector3D& vLocal, CameraTranslationOption option = TranslateViewCenter );
@@ -97,10 +98,12 @@ public:
 
     Q_INVOKABLE void tilt(float angle);
     Q_INVOKABLE void pan(float angle);
+    Q_INVOKABLE void pan(float angle, const QVector3D &axis);
     Q_INVOKABLE void roll(float angle);
 
     Q_INVOKABLE void tiltAboutViewCenter(float angle);
     Q_INVOKABLE void panAboutViewCenter(float angle);
+    Q_INVOKABLE void panAboutViewCenter(float angle, const QVector3D &axis);
     Q_INVOKABLE void rollAboutViewCenter(float angle);
 
     Q_INVOKABLE void rotate(const QQuaternion& q);
diff --git a/src/input/cameracontroller.cpp b/src/input/cameracontroller.cpp
index d9af1d06f..0efd6d002 100644
--- a/src/input/cameracontroller.cpp
+++ b/src/input/cameracontroller.cpp
@@ -69,6 +69,8 @@ CameraController::CameraController(QObject *parent) :
     m_lookRate( 0.1f ),
     m_translateFast( false ),
     m_multisampleEnabled( true ),
+    m_controlMode( FirstPerson ),
+    m_firstPersonUp( QVector3D( 0.0f, 1.0f, 0.0f ) ),
     m_updateTimer(new QTimer(this))
 {
     m_updateTimer->setInterval(16);
@@ -268,15 +270,30 @@ void CameraController::mouseMoveEvent( QMouseEvent* e )
     float dy = -(m_pos.y() - m_prevPos.y());
     m_prevPos = m_pos;
 
-    if ( m_leftButtonPressed )
-    {
-        m_camera->pan( dx * m_lookRate );
-        m_camera->tilt( dy * m_lookRate );
-    }
-    else if ( m_orbitMode )
-    {
-        m_camera->panAboutViewCenter( dx * m_orbitRate );
-        m_camera->tiltAboutViewCenter( dy * m_orbitRate );
+    if (m_leftButtonPressed) {
+        switch (m_controlMode) {
+        case FreeLook:
+            m_camera->pan(dx * m_lookRate);
+            break;
+
+        case FirstPerson:
+            m_camera->pan(dx * m_lookRate, m_firstPersonUp);
+            break;
+        }
+
+        m_camera->tilt(dy * m_lookRate);
+    } else if (m_orbitMode) {
+        switch (m_controlMode) {
+        case FreeLook:
+            m_camera->panAboutViewCenter(dx * m_orbitRate);
+            break;
+
+        case FirstPerson:
+            m_camera->panAboutViewCenter(dx * m_orbitRate, m_firstPersonUp);
+            break;
+        }
+
+        m_camera->tiltAboutViewCenter(dy * m_orbitRate);
     }
 }
 
@@ -291,6 +308,32 @@ void CameraController::toggleMSAA()
     emit multisampleEnabledChanged();
 }
 
+void CameraController::setControlMode(ControlMode controlMode)
+{
+    if (controlMode != m_controlMode) {
+        m_controlMode = controlMode;
+        emit controlModeChanged();
+    }
+}
+
+CameraController::ControlMode CameraController::controlMode() const
+{
+    return m_controlMode;
+}
+
+void CameraController::setFirstPersonUpVector(const QVector3D &up)
+{
+    if (m_firstPersonUp != up) {
+        m_firstPersonUp = up;
+        emit firstPersonUpVectorChanged();
+    }
+}
+
+QVector3D CameraController::firstPersonUpVector() const
+{
+    return m_firstPersonUp;
+}
+
 bool CameraController::eventFilter(QObject *receiver, QEvent *event)
 {
     switch (event->type()) {
diff --git a/src/input/cameracontroller_p.h b/src/input/cameracontroller_p.h
index 2fc5b7d0e..956400b02 100644
--- a/src/input/cameracontroller_p.h
+++ b/src/input/cameracontroller_p.h
@@ -51,6 +51,7 @@
 #include <QObject>
 
 #include <QPoint>
+#include <QtGui/qvector3d.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -76,6 +77,9 @@ class CameraController : public QObject
     Q_PROPERTY( float lookRate READ lookRate WRITE setLookRate NOTIFY lookRateChanged )
     Q_PROPERTY( bool multisampleEnabled READ isMultisampleEnabled NOTIFY multisampleEnabledChanged )
 
+    Q_PROPERTY( ControlMode controlMode READ controlMode WRITE setControlMode NOTIFY controlModeChanged )
+    Q_PROPERTY( QVector3D firstPersonUpVector READ firstPersonUpVector WRITE setFirstPersonUpVector NOTIFY firstPersonUpVectorChanged )
+
 public:
     explicit CameraController(QObject *parent = 0);
 
@@ -101,6 +105,19 @@ public:
     void update( double t );
 
     bool isMultisampleEnabled() const;
+
+    enum ControlMode {
+        FreeLook,
+        FirstPerson
+    };
+    Q_ENUM(ControlMode)
+
+    void setControlMode( ControlMode controlMode );
+    ControlMode controlMode() const;
+
+    void setFirstPersonUpVector( const QVector3D &up );
+    QVector3D firstPersonUpVector() const;
+
 public Q_SLOTS:
     void toggleMSAA();
 
@@ -114,6 +131,9 @@ Q_SIGNALS:
 
     void multisampleEnabledChanged();
 
+    void controlModeChanged();
+    void firstPersonUpVectorChanged();
+
 private Q_SLOTS:
     void onUpdate();
 
@@ -141,6 +161,9 @@ private:
     bool m_translateFast;
     bool m_multisampleEnabled;
 
+    ControlMode m_controlMode;
+    QVector3D m_firstPersonUp;
+
     QTimer *m_updateTimer;
 };