/****************************************************************************

 Copyright (C) 2002-2013 Gilles Debunne. All rights reserved.

 This file is part of the QGLViewer library version 2.5.0.

 http://www.libqglviewer.com - contact@libqglviewer.com

 This file may be used under the terms of the GNU General Public License 
 versions 2.0 or 3.0 as published by the Free Software Foundation and
 appearing in the LICENSE file included in the packaging of this file.
 In addition, as a special exception, Gilles Debunne gives you certain 
 additional rights, described in the file GPL_EXCEPTION in this package.

 libQGLViewer uses dual licensing. Commercial/proprietary software must
 purchase a libQGLViewer Commercial License.

 This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

*****************************************************************************/

#ifndef QGLVIEWER_CAMERA_H
#define QGLVIEWER_CAMERA_H

#include "manipulatedCameraFrame.h"
#include "keyFrameInterpolator.h"

namespace qglviewer {
/*! \brief A perspective or orthographic camera.
  \class Camera camera.h QGLViewer/camera.h

  A Camera defines some intrinsic parameters (fieldOfView(), position(), viewDirection(),
  upVector()...) and useful positioning tools that ease its placement (showEntireScene(),
  fitSphere(), lookAt()...). It exports its associated OpenGL projection and modelview matrices and
  can interactively be modified using the mouse.

  <h3>Mouse manipulation</h3>

  The position() and orientation() of the Camera are defined by a ManipulatedCameraFrame (retrieved
  using frame()). These methods are just convenient wrappers to the equivalent Frame methods. This
  also means that the Camera frame() can be attached to a Frame::referenceFrame() which enables
  complex Camera setups.

  Different displacements can be performed using the mouse. The list of possible actions is defined
  by the QGLViewer::MouseAction enum. Use QGLViewer::setMouseBinding() to attach a specific action
  to an arbitrary mouse button-state key binding. These actions are detailed in the <a
  href="../mouse.html">mouse page</a>.

  The default button binding are: QGLViewer::ROTATE (left), QGLViewer::ZOOM (middle) and
  QGLViewer::TRANSLATE (right). With this configuration, the Camera \e observes a scene and rotates
  around its revolveAroundPoint(). You can switch between this mode and a fly mode using the
  QGLViewer::CAMERA_MODE (see QGLViewer::toggleCameraMode()) keyboard shortcut (default is 'Space').

  <h3>Other functionalities</h3>

  The type() of the Camera can be Camera::ORTHOGRAPHIC or Camera::PERSPECTIVE (see Type()).
  fieldOfView() is meaningless with Camera::ORTHOGRAPHIC.

  The near and far planes of the Camera are fitted to the scene and determined from
  QGLViewer::sceneRadius(), QGLViewer::sceneCenter() and zClippingCoefficient() by the zNear() and
  zFar() methods. Reasonable values on the scene extends hence have to be provided to the QGLViewer
  in order for the Camera to correctly display the scene. High level positioning methods also use
  this information (showEntireScene(), centerScene()...).

  A Camera holds KeyFrameInterpolator that can be used to save Camera positions and paths. You can
  interactively addKeyFrameToPath() to a given path using the default \c Alt+F[1-12] shortcuts. Use
  playPath() to make the Camera follow the path (default shortcut is F[1-12]). See the <a
  href="../keyboard.html">keyboard page</a> for details on key customization.

  Use cameraCoordinatesOf() and worldCoordinatesOf() to convert to and from the Camera frame()
  coordinate system. projectedCoordinatesOf() and unprojectedCoordinatesOf() will convert from
  screen to 3D coordinates. convertClickToLine() is very useful for analytical object selection.

  Stereo display is possible on machines with quad buffer capabilities (with Camera::PERSPECTIVE
  type() only). Test the <a href="../examples/stereoViewer.html">stereoViewer example</a> to check.

  A Camera can also be used outside of a QGLViewer or even without OpenGL for its coordinate system
  conversion capabilities. Note however that some of them explicitly rely on the presence of a
  Z-buffer. \nosubgrouping */
class QGLVIEWER_EXPORT Camera : public QObject
{
#ifndef DOXYGEN
	friend class ::QGLViewer;
#endif

	Q_OBJECT

public:
	Camera();
	virtual ~Camera();

	Camera(const Camera& camera);
	Camera& operator=(const Camera& camera);


	/*! Enumerates the two possible types of Camera.

	See type() and setType(). This type mainly defines different Camera projection matrix (see
	loadProjectionMatrix()). Many other methods (pointUnderPixel(), convertClickToLine(),
	projectedCoordinatesOf(), pixelGLRatio()...) take this Type into account. */
	enum Type { PERSPECTIVE, ORTHOGRAPHIC };

	/*! @name Position and orientation */
	//@{
public:
	/*! Returns the Camera position (the eye), defined in the world coordinate system.

	Use setPosition() to set the Camera position. Other convenient methods are showEntireScene() or
	fitSphere(). Actually returns \c frame()->position().

	This position corresponds to the projection center of a Camera::PERSPECTIVE Camera. It is not
	located in the image plane, which is at a zNear() distance ahead. */
	Vec position() const { return frame()->position(); }

	/*! Returns the normalized up vector of the Camera, defined in the world coordinate system.

	Set using setUpVector() or setOrientation(). It is orthogonal to viewDirection() and to
	rightVector().

	It corresponds to the Y axis of the associated frame() (actually returns
	frame()->inverseTransformOf(Vec(0.0, 1.0, 0.0)) ). */
	Vec upVector() const
	{
		return frame()->inverseTransformOf(Vec(0.0, 1.0, 0.0));
	}
	/*! Returns the normalized view direction of the Camera, defined in the world coordinate system.

	Change this value using setViewDirection(), lookAt() or setOrientation(). It is orthogonal to
	upVector() and to rightVector().

	This corresponds to the negative Z axis of the frame() ( frame()->inverseTransformOf(Vec(0.0,
	0.0, -1.0)) ). */
	Vec viewDirection() const { return frame()->inverseTransformOf(Vec(0.0, 0.0, -1.0)); }

	/*! Returns the normalized right vector of the Camera, defined in the world coordinate system.

	This vector lies in the Camera horizontal plane, directed along the X axis (orthogonal to
	upVector() and to viewDirection()). Set using setUpVector(), lookAt() or setOrientation().

	Simply returns frame()->inverseTransformOf(Vec(1.0, 0.0, 0.0)). */
	Vec rightVector() const
	{
		return frame()->inverseTransformOf(Vec(1.0, 0.0, 0.0));
	}

	/*! Returns the Camera orientation, defined in the world coordinate system.

	Actually returns \c frame()->orientation(). Use setOrientation(), setUpVector() or lookAt() to
	set the Camera orientation. */
	Quaternion orientation() const { return frame()->orientation(); }

	void setFromModelViewMatrix(const GLdouble* const modelViewMatrix);
	void setFromProjectionMatrix(const float matrix[12]);

public Q_SLOTS:
	/*! Sets the Camera position() (the eye), defined in the world coordinate system. */
	void setPosition(const Vec& pos) { frame()->setPosition(pos); }
	void setOrientation(const Quaternion& q);
	void setOrientation(float theta, float phi);
	void setUpVector(const Vec& up, bool noMove=true);
	void setViewDirection(const Vec& direction);
	//@}


	/*! @name Positioning tools */
	//@{
public Q_SLOTS:
	void lookAt(const Vec& target);
	void showEntireScene();
	void fitSphere(const Vec& center, float radius);
	void fitBoundingBox(const Vec& min, const Vec& max);
	void fitScreenRegion(const QRect& rectangle);
	void centerScene();
	void interpolateToZoomOnPixel(const QPoint& pixel);
	void interpolateToFitScene();
	void interpolateTo(const Frame& fr, float duration);
	//@}


	/*! @name Frustum */
	//@{
public:
	/*! Returns the Camera::Type of the Camera.

	Set by setType(). Mainly used by loadProjectionMatrix().

	A Camera::PERSPECTIVE Camera uses a classical projection mainly defined by its fieldOfView().

	With a Camera::ORTHOGRAPHIC type(), the fieldOfView() is meaningless and the width and height of
	the Camera frustum are inferred from the distance to the revolveAroundPoint() using
	getOrthoWidthHeight().

	Both types use zNear() and zFar() (to define their clipping planes) and aspectRatio() (for
	frustum shape). */
	Type type() const { return type_; }

	/*! Returns the vertical field of view of the Camera (in radians).

	Value is set using setFieldOfView(). Default value is pi/4 radians. This value is meaningless if
	the Camera type() is Camera::ORTHOGRAPHIC.

	The field of view corresponds the one used in \c gluPerspective (see manual). It sets the Y
	(vertical) aperture of the Camera. The X (horizontal) angle is inferred from the window aspect
	ratio (see aspectRatio() and horizontalFieldOfView()).

	Use setFOVToFitScene() to adapt the fieldOfView() to a given scene. */
	float fieldOfView() const { return fieldOfView_; }

	/*! Returns the horizontal field of view of the Camera (in radians).

	Value is set using setHorizontalFieldOfView() or setFieldOfView(). These values
	are always linked by:
	\code
	horizontalFieldOfView() = 2.0 * atan ( tan(fieldOfView()/2.0) * aspectRatio() ).
	\endcode */
	float horizontalFieldOfView() const { return 2.0 * atan ( tan(fieldOfView()/2.0) * aspectRatio() ); }

	/*! Returns the Camera aspect ratio defined by screenWidth() / screenHeight().

	When the Camera is attached to a QGLViewer, these values and hence the aspectRatio() are
	automatically fitted to the viewer's window aspect ratio using setScreenWidthAndHeight(). */
	float aspectRatio() const { return static_cast<float>(screenWidth_)/static_cast<float>(screenHeight_); }
	/*! Returns the width (in pixels) of the Camera screen.

	Set using setScreenWidthAndHeight(). This value is automatically fitted to the QGLViewer's
	window dimensions when the Camera is attached to a QGLViewer. See also QGLWidget::width() */
	int screenWidth() const { return screenWidth_; }
	/*! Returns the height (in pixels) of the Camera screen.

	Set using setScreenWidthAndHeight(). This value is automatically fitted to the QGLViewer's
	window dimensions when the Camera is attached to a QGLViewer. See also QGLWidget::height() */
	int screenHeight() const { return screenHeight_; }
	void getViewport(GLint viewport[4]) const;
	float pixelGLRatio(const Vec& position) const;

	/*! Returns the coefficient which is used to set zNear() when the Camera is inside the sphere
	defined by sceneCenter() and zClippingCoefficient() * sceneRadius().

	In that case, the zNear() value is set to zNearCoefficient() * zClippingCoefficient() *
	sceneRadius(). See the zNear() documentation for details.

	Default value is 0.005, which is appropriate for most applications. In case you need a high
	dynamic ZBuffer precision, you can increase this value (~0.1). A lower value will prevent
	clipping of very close objects at the expense of a worst Z precision.

	Only meaningful when Camera type is Camera::PERSPECTIVE. */
	float zNearCoefficient() const { return zNearCoef_; }
	/*! Returns the coefficient used to position the near and far clipping planes.

	The near (resp. far) clipping plane is positioned at a distance equal to zClippingCoefficient() *
	sceneRadius() in front of (resp. behind) the sceneCenter(). This garantees an optimal use of
	the z-buffer range and minimizes aliasing. See the zNear() and zFar() documentations.

	Default value is square root of 3.0 (so that a cube of size sceneRadius() is not clipped).

	However, since the sceneRadius() is used for other purposes (see showEntireScene(), flySpeed(),
	...) and you may want to change this value to define more precisely the location of the clipping
	planes. See also zNearCoefficient().

	For a total control on clipping planes' positions, an other option is to overload the zNear()
	and zFar() methods. See the <a href="../examples/standardCamera.html">standardCamera example</a>.

	\attention When QGLViewer::cameraPathAreEdited(), this value is set to 5.0 so that the Camera
	paths are not clipped. The previous zClippingCoefficient() value is restored back when you leave
	this mode. */
	float zClippingCoefficient() const { return zClippingCoef_; }

	virtual float zNear() const;
	virtual float zFar()  const;
	virtual void getOrthoWidthHeight(GLdouble& halfWidth, GLdouble& halfHeight) const;
	void getFrustumPlanesCoefficients(GLdouble coef[6][4]) const;

public Q_SLOTS:
	void setType(Type type);

	void setFieldOfView(float fov);

	/*! Sets the horizontalFieldOfView() of the Camera (in radians).

	horizontalFieldOfView() and fieldOfView() are linked by the aspectRatio(). This method actually
	calls setFieldOfView(( 2.0 * atan (tan(hfov / 2.0) / aspectRatio()) )) so that a call to
	horizontalFieldOfView() returns the expected value. */
	void setHorizontalFieldOfView(float hfov) { setFieldOfView( 2.0 * atan (tan(hfov / 2.0) / aspectRatio()) ); }

	void setFOVToFitScene();

	/*! Defines the Camera aspectRatio().

	This value is actually inferred from the screenWidth() / screenHeight() ratio. You should use
	setScreenWidthAndHeight() instead.

	This method might however be convenient when the Camera is not associated with a QGLViewer. It
	actually sets the screenHeight() to 100 and the screenWidth() accordingly. See also
	setFOVToFitScene().

	\note If you absolutely need an aspectRatio() that does not correspond to your viewer's window
	dimensions, overload loadProjectionMatrix() or multiply the created GL_PROJECTION matrix by a
	scaled diagonal matrix in your QGLViewer::draw() method. */
	void setAspectRatio(float aspect) { setScreenWidthAndHeight(int(100.0*aspect), 100); }

	void setScreenWidthAndHeight(int width, int height);
	/*! Sets the zNearCoefficient() value. */
	void setZNearCoefficient(float coef) { zNearCoef_ = coef; projectionMatrixIsUpToDate_ = false; }
	/*! Sets the zClippingCoefficient() value. */
	void setZClippingCoefficient(float coef) { zClippingCoef_ = coef; projectionMatrixIsUpToDate_ = false; }
	//@}


	/*! @name Scene radius and center */
	//@{
public:
	/*! Returns the radius of the scene observed by the Camera.

	You need to provide such an approximation of the scene dimensions so that the Camera can adapt
	its zNear() and zFar() values. See the sceneCenter() documentation.

	See also setSceneBoundingBox().

	Note that QGLViewer::sceneRadius() (resp. QGLViewer::setSceneRadius()) simply call this method
	(resp. setSceneRadius()) on its associated QGLViewer::camera(). */
	float sceneRadius() const { return sceneRadius_; }

	/*! Returns the position of the scene center, defined in the world coordinate system.

	The scene observed by the Camera should be roughly centered on this position, and included in a
	sceneRadius() sphere. This approximate description of the scene permits a zNear() and zFar()
	clipping planes definition, and allows convenient positioning methods such as showEntireScene().

	Default value is (0,0,0) (world origin). Use setSceneCenter() to change it. See also
	setSceneBoundingBox().

	Note that QGLViewer::sceneCenter() (resp. QGLViewer::setSceneCenter()) simply call this method
	(resp. setSceneCenter()) on its associated QGLViewer::camera(). */
	Vec sceneCenter() const { return sceneCenter_; }
	float distanceToSceneCenter() const;

public Q_SLOTS:
	void setSceneRadius(float radius);
	void setSceneCenter(const Vec& center);
	bool setSceneCenterFromPixel(const QPoint& pixel);
	void setSceneBoundingBox(const Vec& min, const Vec& max);
	//@}


	/*! @name Revolve Around Point */
	//@{
public Q_SLOTS:
	void setRevolveAroundPoint(const Vec& rap);
	bool setRevolveAroundPointFromPixel(const QPoint& pixel);

public:
	/*! The point the Camera revolves around with the QGLViewer::ROTATE mouse binding. Defined in world coordinate system.

	Default value is the sceneCenter().

	\attention setSceneCenter() changes this value. */
	Vec revolveAroundPoint() const { return frame()->revolveAroundPoint(); }
	//@}


	/*! @name Associated frame */
	//@{
public:
	/*! Returns the ManipulatedCameraFrame attached to the Camera.

	This ManipulatedCameraFrame defines its position() and orientation() and can translate mouse
	events into Camera displacement. Set using setFrame(). */
	ManipulatedCameraFrame* frame() const { return frame_; }
public Q_SLOTS:
	void setFrame(ManipulatedCameraFrame* const mcf);
	//@}


	/*! @name KeyFramed paths */
	//@{
public:
	KeyFrameInterpolator* keyFrameInterpolator(int i) const;

public Q_SLOTS:
	void setKeyFrameInterpolator(int i, KeyFrameInterpolator* const kfi);

	virtual void addKeyFrameToPath(int i);
	virtual void playPath(int i);
	virtual void deletePath(int i);
	virtual void resetPath(int i);
	virtual void drawAllPaths();
	//@}


	/*! @name OpenGL matrices */
	//@{
public:
	virtual void loadProjectionMatrix(bool reset=true) const;
	virtual void loadModelViewMatrix(bool reset=true) const;
	void computeProjectionMatrix() const;
	void computeModelViewMatrix() const;

	virtual void loadProjectionMatrixStereo(bool leftBuffer=true) const;
	virtual void loadModelViewMatrixStereo(bool leftBuffer=true) const;

	void getProjectionMatrix(GLdouble m[16]) const;
	void getModelViewMatrix(GLdouble m[16]) const;
	void getModelViewProjectionMatrix(GLdouble m[16]) const;

#ifndef DOXYGEN
	// Required for windows which otherwise silently fills
	void getProjectionMatrix(GLfloat m[16]) const;
	void getModelViewMatrix(GLfloat m[16]) const;
#endif
	//@}


	/*! @name Drawing */
	//@{
#ifndef DOXYGEN
	static void drawCamera(float scale=1.0, float aspectRatio=1.33, float fieldOfView=M_PI/4.0);
#endif
	virtual void draw(bool drawFarPlane=true, float scale=1.0) const;
	//@}


	/*! @name World to Camera coordinate systems conversions */
	//@{
public:
	/*! Returns the Camera frame coordinates of a point \p src defined in world coordinates.

	worldCoordinatesOf() performs the inverse transformation.

	Note that the point coordinates are simply converted in a different coordinate system. They are
	not projected on screen. Use projectedCoordinatesOf() for that. */
	Vec cameraCoordinatesOf(const Vec& src) const { return frame()->coordinatesOf(src); }
	/*! Returns the world coordinates of the point whose position \p src is defined in the Camera
	coordinate system.

	cameraCoordinatesOf() performs the inverse transformation. */
	Vec worldCoordinatesOf(const Vec& src) const { return frame()->inverseCoordinatesOf(src); }
	void getCameraCoordinatesOf(const float src[3], float res[3]) const;
	void getWorldCoordinatesOf(const float src[3], float res[3]) const;
	//@}


	/*! @name 2D screen to 3D world coordinate systems conversions */
	//@{
public:
	Vec projectedCoordinatesOf(const Vec& src, const Frame* frame=NULL) const;
	Vec unprojectedCoordinatesOf(const Vec& src, const Frame* frame=NULL) const;
	void getProjectedCoordinatesOf(const float src[3], float res[3], const Frame* frame=NULL) const;
	void getUnprojectedCoordinatesOf(const float src[3], float res[3], const Frame* frame=NULL) const;
	void convertClickToLine(const QPoint& pixel, Vec& orig, Vec& dir) const;
	Vec pointUnderPixel(const QPoint& pixel, bool& found) const;
	//@}


	/*! @name Fly speed */
	//@{
public:
	/*! Returns the fly speed of the Camera.

	Simply returns frame()->flySpeed(). See the ManipulatedCameraFrame::flySpeed() documentation.
	This value is only meaningful when the MouseAction bindings is QGLViewer::MOVE_FORWARD or
	QGLViewer::MOVE_BACKWARD.

	Set to 1% of the sceneRadius() by setSceneRadius(). See also setFlySpeed(). */
	float flySpeed() const { return frame()->flySpeed(); }
public Q_SLOTS:
	/*! Sets the Camera flySpeed().

	\attention This value is modified by setSceneRadius(). */
	void setFlySpeed(float speed) { frame()->setFlySpeed(speed); }
	//@}


	/*! @name Stereo parameters */
	//@{
public:
	/*! Returns the user's inter-ocular distance (in meters). Default value is 0.062m, which fits most people.

	loadProjectionMatrixStereo() uses this value to define the Camera offset and frustum. See
	setIODistance(). */
	float IODistance() const { return IODistance_; }

	/*! Returns the physical distance between the user's eyes and the screen (in meters).

	physicalDistanceToScreen() and focusDistance() represent the same distance. The former is
	expressed in physical real world units, while the latter is expressed in OpenGL virtual world
	units.

	This is a helper function. It simply returns physicalScreenWidth() / 2.0 / tan(horizontalFieldOfView() / 2.0); */
	float physicalDistanceToScreen() const { return physicalScreenWidth() / 2.0f / tan(horizontalFieldOfView() / 2.0); }

	/*! Returns the physical screen width, in meters. Default value is 0.5m (average monitor width).

	Used for stereo display only (see loadModelViewMatrixStereo() and loadProjectionMatrixStereo()).
	Set using setPhysicalScreenWidth(). */
	float physicalScreenWidth() const { return physicalScreenWidth_; }

	/*! Returns the focus distance used by stereo display, expressed in OpenGL units.

	This is the distance in the virtual world between the Camera and the plane where the horizontal
	stereo parallax is null (the stereo left and right cameras' lines of sigth cross at this distance).

	This distance is the virtual world equivalent of the real-world physicalDistanceToScreen().

	\attention This value is modified by QGLViewer::setSceneRadius(), setSceneRadius() and
	setFieldOfView(). When one of these values is modified, focusDistance() is set to sceneRadius()
	/ tan(fieldOfView()/2), which provides good results. */
	float focusDistance() const { return focusDistance_; }
public Q_SLOTS:
	/*! Sets the IODistance(). */
	void setIODistance(float distance) { IODistance_ = distance; }

#ifndef DOXYGEN
	/*! This method is deprecated. Use setPhysicalScreenWidth() instead. */
	void setPhysicalDistanceToScreen(float distance) { Q_UNUSED(distance); qWarning("setPhysicalDistanceToScreen is deprecated, use setPhysicalScreenWidth instead"); }
#endif

	/*! Sets the physical screen (monitor or projected wall) width (in meters). */
	void setPhysicalScreenWidth(float width) { physicalScreenWidth_ = width; }

	/*! Sets the focusDistance(), in OpenGL scene units. */
	void setFocusDistance(float distance) { focusDistance_ = distance; }
	//@}


	/*! @name XML representation */
	//@{
public:
	virtual QDomElement domElement(const QString& name, QDomDocument& document) const;
public Q_SLOTS:
	virtual void initFromDOMElement(const QDomElement& element);
	//@}


private Q_SLOTS:
	void onFrameModified();

private:
	// F r a m e
	ManipulatedCameraFrame* frame_;

	// C a m e r a   p a r a m e t e r s
	int screenWidth_, screenHeight_;  // size of the window, in pixels
	float fieldOfView_; // in radians
	Vec sceneCenter_;
	float sceneRadius_; // OpenGL units
	float zNearCoef_;
	float zClippingCoef_;
	float orthoCoef_;
	Type type_; // PERSPECTIVE or ORTHOGRAPHIC
	mutable GLdouble modelViewMatrix_[16]; // Buffered model view matrix.
	mutable bool modelViewMatrixIsUpToDate_;
	mutable GLdouble projectionMatrix_[16]; // Buffered projection matrix.
	mutable bool projectionMatrixIsUpToDate_;

	// S t e r e o   p a r a m e t e r s
	float IODistance_;		     // inter-ocular distance, in meters
	float focusDistance_;	     // in scene units
	float physicalScreenWidth_;	     // in meters

	// P o i n t s   o f   V i e w s   a n d   K e y F r a m e s
	QMap<int, KeyFrameInterpolator*> kfi_;
	KeyFrameInterpolator* interpolationKfi_;
};

} // namespace qglviewer

#endif // QGLVIEWER_CAMERA_H
