A perspective or orthographic camera. More...

#include <QGLViewer/camera.h>

Public Types
enum	Type { PERSPECTIVE, ORTHOGRAPHIC }
Public Member Functions
	Camera ()
	Camera (const Camera &camera)
Camera &	operator= (const Camera &camera)
virtual	~Camera ()
Private Attributes
float	fieldOfView_
float	focusDistance_
ManipulatedCameraFrame *	frame_
KeyFrameInterpolator *	interpolationKfi_
float	IODistance_
QMap< int, KeyFrameInterpolator * >	kfi_
GLdouble	modelViewMatrix_ [16]
float	orthoCoef_
float	physicalScreenWidth_
GLdouble	projectionMatrix_ [16]
Vec	sceneCenter_
float	sceneRadius_
int	screenHeight_
int	screenWidth_
Type	type_
float	zClippingCoef_
float	zNearCoef_
Friends
class	::QGLViewer
Position and orientation
Vec	position () const
Vec	upVector () const
Vec	viewDirection () const
Vec	rightVector () const
Quaternion	orientation () const
void	setFromModelViewMatrix (const GLdouble *const modelViewMatrix)
void	setFromProjectionMatrix (const float matrix[12])
void	setPosition (const Vec &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)
Positioning tools
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)
Frustum
Type	type () const
float	fieldOfView () const
float	horizontalFieldOfView () const
float	aspectRatio () const
int	screenWidth () const
int	screenHeight () const
void	getViewport (GLint viewport[4]) const
float	pixelGLRatio (const Vec &position) const
float	zNearCoefficient () const
float	zClippingCoefficient () const
virtual float	zNear () const
virtual float	zFar () const
virtual void	getOrthoWidthHeight (GLdouble &halfWidth, GLdouble &halfHeight) const
void	getFrustumPlanesCoefficients (GLdouble coef[6][4]) const
void	setType (Type type)
void	setFieldOfView (float fov)
void	setHorizontalFieldOfView (float hfov)
void	setFOVToFitScene ()
void	setAspectRatio (float aspect)
void	setScreenWidthAndHeight (int width, int height)
void	setZNearCoefficient (float coef)
void	setZClippingCoefficient (float coef)
Scene radius and center
float	sceneRadius () const
Vec	sceneCenter () const
float	distanceToSceneCenter () const
void	setSceneRadius (float radius)
void	setSceneCenter (const Vec &center)
bool	setSceneCenterFromPixel (const QPoint &pixel)
void	setSceneBoundingBox (const Vec &min, const Vec &max)
Revolve Around Point
Vec	revolveAroundPoint () const
void	setRevolveAroundPoint (const Vec &rap)
bool	setRevolveAroundPointFromPixel (const QPoint &pixel)
Associated frame
ManipulatedCameraFrame *	frame () const
void	setFrame (ManipulatedCameraFrame *const mcf)
KeyFramed paths
KeyFrameInterpolator *	keyFrameInterpolator (int i) const
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 ()
OpenGL matrices
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
void	getProjectionMatrix (GLfloat m[16]) const
void	getModelViewMatrix (GLfloat m[16]) const
Drawing
virtual void	draw (bool drawFarPlane=true, float scale=1.0) const
static void	drawCamera (float scale=1.0, float aspectRatio=1.33, float fieldOfView=M_PI/4.0)
World to Camera coordinate systems conversions
Vec	cameraCoordinatesOf (const Vec &src) const
Vec	worldCoordinatesOf (const Vec &src) const
void	getCameraCoordinatesOf (const float src[3], float res[3]) const
void	getWorldCoordinatesOf (const float src[3], float res[3]) const
2D screen to 3D world coordinate systems conversions
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
Fly speed
float	flySpeed () const
void	setFlySpeed (float speed)
Stereo parameters
float	IODistance () const
float	physicalDistanceToScreen () const
float	physicalScreenWidth () const
float	focusDistance () const
void	setIODistance (float distance)
void	setPhysicalDistanceToScreen (float distance)
void	setPhysicalScreenWidth (float width)
void	setFocusDistance (float distance)
XML representation
virtual QDomElement	domElement (const QString &name, QDomDocument &document) const
virtual void	initFromDOMElement (const QDomElement &element)

Detailed Description

A perspective or orthographic camera.

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.

Mouse manipulation

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 mouse page.

The default button binding are: QGLViewer::ROTATE (left), QGLViewer::ZOOM (middle) and QGLViewer::TRANSLATE (right). With this configuration, the Camera 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').

Other functionalities

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 Alt+F[1-12] shortcuts. Use playPath() to make the Camera follow the path (default shortcut is F[1-12]). See the keyboard page 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 stereoViewer example 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.

Definition at line 81 of file camera.h.

Member Enumeration Documentation

enum qglviewer::Camera::Type

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.

Enumerator:

PERSPECTIVE
ORTHOGRAPHIC

Definition at line 102 of file camera.h.

Constructor & Destructor Documentation

Camera::Camera ( )

Default constructor.

sceneCenter() is set to (0,0,0) and sceneRadius() is set to 1.0. type() is Camera::PERSPECTIVE, with a M_PI/4 fieldOfView().

See IODistance(), physicalDistanceToScreen(), physicalScreenWidth() and focusDistance() documentations for default stereo parameter values.

Definition at line 37 of file camera.cpp.

Camera::~Camera ( ) [virtual]

Virtual destructor.

The frame() is deleted, but the different keyFrameInterpolator() are not deleted (in case they are shared).

Definition at line 85 of file camera.cpp.

Camera::Camera ( const Camera & camera )

Copy constructor. Performs a deep copy using operator=().

Definition at line 93 of file camera.cpp.

Member Function Documentation

void Camera::addKeyFrameToPath ( int i ) [virtual, slot]

Adds the current Camera position() and orientation() as a keyFrame to the path number i.

This method can also be used if you simply want to save a Camera point of view (a path made of a single keyFrame). Use playPath() to make the Camera play the keyFrame path (resp. restore the point of view). Use deletePath() to clear the path.

The default keyboard shortcut for this method is Alt+F[1-12]. Set QGLViewer::pathKey() and QGLViewer::addKeyFrameKeyboardModifiers().

If you use directly this method and the keyFrameInterpolator(i) does not exist, a new one is created. Its KeyFrameInterpolator::interpolated() signal should then be connected to the QGLViewer::updateGL() slot (see setKeyFrameInterpolator()).

Definition at line 1562 of file camera.cpp.

float qglviewer::Camera::aspectRatio ( ) const [inline]

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().

Definition at line 223 of file camera.h.

Vec qglviewer::Camera::cameraCoordinatesOf ( const Vec & src ) const [inline]

Returns the Camera frame coordinates of a point 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.

Definition at line 435 of file camera.h.

void Camera::centerScene ( ) [slot]

Moves the Camera so that its sceneCenter() is projected on the center of the window. The orientation() and fieldOfView() are unchanged.

Simply projects the current position on a line passing through sceneCenter(). See also showEntireScene().

Definition at line 939 of file camera.cpp.

void Camera::computeModelViewMatrix ( ) const

Computes the modelView matrix associated with the Camera's position() and orientation().

This matrix converts from the world coordinates system to the Camera coordinates system, so that coordinates can then be projected on screen using the projection matrix (see computeProjectionMatrix()).

Use getModelViewMatrix() to retrieve this matrix.

Note:: You must call this method if your Camera is not associated with a QGLViewer and is used for offscreen computations (using (un)projectedCoordinatesOf() for instance). loadModelViewMatrix() does it otherwise.

Definition at line 373 of file camera.cpp.

void Camera::computeProjectionMatrix ( ) const

Computes the projection matrix associated with the Camera.

If type() is Camera::PERSPECTIVE, defines a GL_PROJECTION matrix similar to what would gluPerspective() do using the fieldOfView(), window aspectRatio(), zNear() and zFar() parameters.

If type() is Camera::ORTHOGRAPHIC, the projection matrix is as what glOrtho() would do. Frustum's width and height are set using getOrthoWidthHeight().

Both types use zNear() and zFar() to place clipping planes. These values are determined from sceneRadius() and sceneCenter() so that they best fit the scene size.

Use getProjectionMatrix() to retrieve this matrix. Overload loadProjectionMatrix() if you want your Camera to use an exotic projection matrix.

Note:: You must call this method if your Camera is not associated with a QGLViewer and is used for offscreen computations (using (un)projectedCoordinatesOf() for instance). loadProjectionMatrix() does it otherwise.

Definition at line 327 of file camera.cpp.

void Camera::convertClickToLine	(	const QPoint &	pixel,
		Vec &	orig,
		Vec &	dir
	)		const

Gives the coefficients of a 3D half-line passing through the Camera eye and pixel (x,y).

The origin of the half line (eye position) is stored in orig, while dir contains the properly oriented and normalized direction of the half line.

x and y are expressed in Qt format (origin in the upper left corner). Use screenHeight() - y to convert to OpenGL units.

This method is useful for analytical intersection in a selection method.

See the select example for an illustration.

Definition at line 1804 of file camera.cpp.

void Camera::deletePath ( int i ) [virtual, slot]

Deletes the keyFrameInterpolator() of index i.

Disconnect the keyFrameInterpolator() KeyFrameInterpolator::interpolated() signal before deleting the keyFrameInterpolator() if needed:

disconnect(camera()->keyFrameInterpolator(i), SIGNAL(interpolated()), this, SLOT(updateGL()));
camera()->deletePath(i);

Definition at line 1614 of file camera.cpp.

float Camera::distanceToSceneCenter ( ) const

Returns the distance from the Camera center to sceneCenter(), projected along the Camera Z axis. Used by zNear() and zFar() to optimize the Z range.

Definition at line 280 of file camera.cpp.

QDomElement Camera::domElement	(	const QString &	name,
		QDomDocument &	document
	)		const `[virtual]`

Returns an XML QDomElement that represents the Camera.

name is the name of the QDomElement tag. doc is the QDomDocument factory used to create QDomElement.

Concatenates the Camera parameters, the ManipulatedCameraFrame::domElement() and the paths' KeyFrameInterpolator::domElement().

Use initFromDOMElement() to restore the Camera state from the resulting QDomElement.

If you want to save the Camera state in a file, use:

  QDomDocument document("myCamera");
  doc.appendChild( myCamera->domElement("Camera", document) );

  QFile f("myCamera.xml");
  if (f.open(IO_WriteOnly))
    {
      QTextStream out(&f);
      document.save(out, 2);
    }

Note that the QGLViewer::camera() is automatically saved by QGLViewer::saveStateToFile() when a QGLViewer is closed. Use QGLViewer::restoreStateFromFile() to restore it back.

Definition at line 1667 of file camera.cpp.

void Camera::draw	(	bool	drawFarPlane = `true`,
		float	scale = `1.0`
	)		const `[virtual]`

Draws a representation of the Camera in the 3D world.

The near and far planes are drawn as quads, the frustum is drawn using lines and the camera up vector is represented by an arrow to disambiguate the drawing. See the standardCamera example for an illustration.

Note that the current glColor and glPolygonMode are used to draw the near and far planes. See the frustumCulling example for an example of semi-transparent plane drawing. Similarly, the current glLineWidth and glColor is used to draw the frustum outline.

When drawFarPlane is false, only the near plane is drawn. scale can be used to scale the drawing: a value of 1.0 (default) will draw the Camera's frustum at its actual size.

This method assumes that the glMatrixMode is GL_MODELVIEW and that the current ModelView matrix corresponds to the world coordinate system (as it is at the beginning of QGLViewer::draw()). The Camera is then correctly positioned and orientated.

Note:: The drawing of a QGLViewer's own QGLViewer::camera() should not be visible, but may create artefacts due to numerical imprecisions.

Definition at line 1857 of file camera.cpp.

void Camera::drawAllPaths ( ) [virtual, slot]

Draws all the Camera paths defined by the keyFrameInterpolator().

Simply calls KeyFrameInterpolator::drawPath() for all the defined paths. The path color is the current glColor().

Attention:: The OpenGL state is modified by this method: see KeyFrameInterpolator::drawPath().

Definition at line 1630 of file camera.cpp.

void Camera::drawCamera	(	float	scale = `1.0`,
		float	aspectRatio = `1.33`,
		float	fieldOfView = `M_PI/4.0`
	)		`[static]`

This method has been deprecated in libQGLViewer version 2.2.0

Definition at line 1831 of file camera.cpp.

float qglviewer::Camera::fieldOfView ( ) const [inline]

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 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.

Definition at line 208 of file camera.h.

void Camera::fitBoundingBox	(	const Vec &	min,
		const Vec &	max
	)		`[slot]`

Moves the Camera so that the (world axis aligned) bounding box (min, max) is entirely visible, using fitSphere().

Definition at line 986 of file camera.cpp.

void Camera::fitScreenRegion ( const QRect & rectangle ) [slot]

Moves the Camera so that the rectangular screen region defined by rectangle (pixel units, with origin in the upper left corner) fits the screen.

The Camera is translated (its orientation() is unchanged) so that rectangle is entirely visible. Since the pixel coordinates only define a frustum in 3D, it's the intersection of this frustum with a plane (orthogonal to the viewDirection() and passing through the sceneCenter()) that is used to define the 3D rectangle that is eventually fitted.

Definition at line 1000 of file camera.cpp.

void Camera::fitSphere	(	const Vec &	center,
		float	radius
	)		`[slot]`

Moves the Camera so that the sphere defined by (center, radius) is visible and fits the window.

The Camera is simply translated along its viewDirection() so that the sphere fits the screen. Its orientation() and its fieldOfView() are unchanged.

You should therefore orientate the Camera before you call this method. See lookAt(), setOrientation() and setUpVector().

Definition at line 962 of file camera.cpp.

float qglviewer::Camera::flySpeed ( ) const [inline]

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().

Definition at line 468 of file camera.h.

float qglviewer::Camera::focusDistance ( ) const [inline]

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.

Definition at line 511 of file camera.h.

ManipulatedCameraFrame* qglviewer::Camera::frame ( ) const [inline]

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().

Definition at line 372 of file camera.h.

void Camera::getCameraCoordinatesOf	(	const float	src[3],
		float	res[3]
	)		const

Same as cameraCoordinatesOf(), but with float[3] parameters (src and res may be identical pointers).

Definition at line 1339 of file camera.cpp.

void Camera::getFrustumPlanesCoefficients ( GLdouble coef[6][4] ) const

Returns the 6 plane equations of the Camera frustum.

The six 4-component vectors of coef respectively correspond to the left, right, near, far, top and bottom Camera frustum planes. Each vector holds a plane equation of the form:

a*x + b*y + c*z + d = 0

where a, b, c and d are the 4 components of each vector, in that order.

See the frustumCulling example for an application.

This format is compatible with the glClipPlane() function. One camera frustum plane can hence be applied in an other viewer to visualize the culling results:

 // Retrieve plane equations
 GLdouble coef[6][4];
 mainViewer->camera()->getFrustumPlanesCoefficients(coef);

 // These two additional clipping planes (which must have been enabled)
 // will reproduce the mainViewer's near and far clipping.
 glClipPlane(GL_CLIP_PLANE0, coef[2]);
 glClipPlane(GL_CLIP_PLANE1, coef[3]);

Definition at line 1985 of file camera.cpp.

void Camera::getModelViewMatrix ( GLdouble m[16] ) const

Fills m with the Camera modelView matrix values.

First calls computeModelViewMatrix() to define the Camera modelView matrix.

Note that this matrix is usually not the one you would get from a glGetDoublev(GL_MODELVIEW_MATRIX, m). It actually represents the state of the GL_MODELVIEW after QGLViewer::preDraw(), at the beginning of QGLViewer::draw(). It converts from the world to the Camera coordinate system. As soon as you modify the GL_MODELVIEW in your QGLViewer::draw() method, the two matrices differ.

The result is an OpenGL 4x4 matrix, which is given in column-major order (see glMultMatrix man page for details).

Definition at line 612 of file camera.cpp.

void Camera::getModelViewMatrix ( GLfloat m[16] ) const

Definition at line 653 of file camera.cpp.

void Camera::getModelViewProjectionMatrix ( GLdouble m[16] ) const

Fills m with the product of the ModelView and Projection matrices.

Calls getModelViewMatrix() and getProjectionMatrix() and then fills m with the product of these two matrices.

Definition at line 624 of file camera.cpp.

void Camera::getOrthoWidthHeight	(	GLdouble &	halfWidth,
		GLdouble &	halfHeight
	)		const `[virtual]`

Returns the halfWidth and halfHeight of the Camera orthographic frustum.

These values are only valid and used when the Camera is of type() Camera::ORTHOGRAPHIC. They are expressed in OpenGL units and are used by loadProjectionMatrix() to define the projection matrix using:

 glOrtho( -halfWidth, halfWidth, -halfHeight, halfHeight, zNear(), zFar() )

These values are proportional to the Camera (z projected) distance to the revolveAroundPoint(). When zooming on the object, the Camera is translated forward and its frustum is narrowed, making the object appear bigger on screen, as intuitively expected.

Overload this method to change this behavior if desired, as is done in the standardCamera example.

Definition at line 301 of file camera.cpp.

void Camera::getProjectedCoordinatesOf	(	const float	src[3],
		float	res[3],
		const Frame *	frame = `NULL`
	)		const

Same as projectedCoordinatesOf(), but with float parameters (src and res can be identical pointers).

Definition at line 1496 of file camera.cpp.

void Camera::getProjectionMatrix ( GLdouble m[16] ) const

Fills m with the Camera projection matrix values.

Calls computeProjectionMatrix() to define the Camera projection matrix.

This matrix only reflects the Camera's internal parameters and it may differ from the GL_PROJECTION matrix retrieved using glGetDoublev(GL_PROJECTION_MATRIX, m). It actually represents the state of the GL_PROJECTION after QGLViewer::preDraw(), at the beginning of QGLViewer::draw(). If you modified the GL_PROJECTION matrix (for instance using QGLViewer::startScreenCoordinatesSystem()), the two results differ.

The result is an OpenGL 4x4 matrix, which is given in column-major order (see glMultMatrix man page for details).

Definition at line 590 of file camera.cpp.

void Camera::getProjectionMatrix ( GLfloat m[16] ) const

Definition at line 644 of file camera.cpp.

void Camera::getUnprojectedCoordinatesOf	(	const float	src[3],
		float	res[3],
		const Frame *	frame = `NULL`
	)		const

Same as unprojectedCoordinatesOf(), but with float parameters (src and res can be identical pointers).

Definition at line 1504 of file camera.cpp.

void Camera::getViewport ( GLint viewport[4] ) const

Fills viewport with the Camera OpenGL viewport.

This method is mainly used in conjunction with gluProject, which requires such a viewport. Returned values are (0, screenHeight(), screenWidth(), - screenHeight()), so that the origin is located in the upper left corner of the window (Qt style coordinate system).

Definition at line 1359 of file camera.cpp.

void Camera::getWorldCoordinatesOf	(	const float	src[3],
		float	res[3]
	)		const

Same as worldCoordinatesOf(), but with float[3] parameters (src and res may be identical pointers).

Definition at line 1347 of file camera.cpp.

float qglviewer::Camera::horizontalFieldOfView ( ) const [inline]

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

Value is set using setHorizontalFieldOfView() or setFieldOfView(). These values are always linked by:

    horizontalFieldOfView() = 2.0 * atan ( tan(fieldOfView()/2.0) * aspectRatio() ).

Definition at line 217 of file camera.h.

void Camera::initFromDOMElement ( const QDomElement & element ) [virtual, slot]

Restores the Camera state from a QDomElement created by domElement().

Use the following code to retrieve a Camera state from a file created using domElement():

 // Load DOM from file
 QDomDocument document;
 QFile f("myCamera.xml");
 if (f.open(IO_ReadOnly))
 {
   document.setContent(&f);
   f.close();
 }

 // Parse the DOM tree
 QDomElement main = document.documentElement();
 myCamera->initFromDOMElement(main);

The frame() pointer is not modified by this method. The frame() state is however modified.

Attention:: The original keyFrameInterpolator() are deleted and should be copied first if they are shared.

Definition at line 1729 of file camera.cpp.

void Camera::interpolateTo	(	const Frame &	fr,
		float	duration
	)		`[slot]`

Smoothly interpolates the Camera on a KeyFrameInterpolator path so that it goes to fr.

fr is expressed in world coordinates. duration tunes the interpolation speed (default is 1 second).

Definition at line 884 of file camera.cpp.

void Camera::interpolateToFitScene ( ) [slot]

Interpolates the Camera on a one second KeyFrameInterpolator path so that the entire scene fits the screen at the end.

The scene is defined by its sceneCenter() and its sceneRadius(). See showEntireScene().

The orientation() of the Camera is not modified. See also interpolateToZoomOnPixel().

Definition at line 855 of file camera.cpp.

void Camera::interpolateToZoomOnPixel ( const QPoint & pixel ) [slot]

Makes the Camera smoothly zoom on the pointUnderPixel() pixel.

Nothing happens if no pointUnderPixel() is found. Otherwise a KeyFrameInterpolator is created that animates the Camera on a one second path that brings the Camera closer to the point under pixel.

See also interpolateToFitScene().

Definition at line 817 of file camera.cpp.

float qglviewer::Camera::IODistance ( ) const [inline]

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().

Definition at line 484 of file camera.h.

KeyFrameInterpolator * Camera::keyFrameInterpolator ( int i ) const

Returns the KeyFrameInterpolator that defines the Camera path number i.

If path i is not defined for this index, the method returns a NULL pointer.

Definition at line 1516 of file camera.cpp.

void Camera::loadModelViewMatrix ( bool reset = true ) const [virtual]

Loads the OpenGL GL_MODELVIEW matrix with the modelView matrix corresponding to the Camera.

Calls computeModelViewMatrix() to compute the Camera's modelView matrix.

This method is used by QGLViewer::preDraw() (called before user's QGLViewer::draw() method) to set the GL_MODELVIEW matrix according to the viewer's QGLViewer::camera() position() and orientation().

As a result, the vertices used in QGLViewer::draw() can be defined in the so called world coordinate system. They are multiplied by this matrix to get converted to the Camera coordinate system, before getting projected using the GL_PROJECTION matrix (see loadProjectionMatrix()).

When reset is true (default), the method loads (overwrites) the GL_MODELVIEW matrix. Setting reset to false simply calls glMultMatrixd (might be useful for some applications).

Overload this method or simply call glLoadMatrixd() at the beginning of QGLViewer::draw() if you want your Camera to use an exotic modelView matrix. See also loadProjectionMatrix().

getModelViewMatrix() returns the 4x4 modelView matrix.

Attention:: glMatrixMode is set to GL_MODELVIEW; If you use several OpenGL contexts and bypass the Qt main refresh loop, you should call QGLWidget::makeCurrent() before this method in order to activate the right OpenGL context.

Definition at line 469 of file camera.cpp.

void Camera::loadModelViewMatrixStereo ( bool leftBuffer = true ) const [virtual]

Same as loadModelViewMatrix() but for a stereo setup.

Only the Camera::PERSPECTIVE type() is supported for stereo mode. See QGLViewer::setStereoDisplay().

The modelView matrix is almost identical to the mono-vision one. It is simply translated along its horizontal axis by a value that depends on stereo parameters (see focusDistance(), IODistance(), and physicalScreenWidth()).

When leftBuffer is true, computes the modelView matrix associated to the left eye (right eye otherwise).

loadProjectionMatrixStereo() explains how to retrieve to resulting matrix.

See the stereoViewer and the anaglyph examples for an illustration.

Attention:: glMatrixMode is set to GL_MODELVIEW.

Definition at line 560 of file camera.cpp.

void Camera::loadProjectionMatrix ( bool reset = true ) const [virtual]

Loads the OpenGL GL_PROJECTION matrix with the Camera projection matrix.

The Camera projection matrix is computed using computeProjectionMatrix().

When reset is true (default), the method clears the previous projection matrix by calling glLoadIdentity before setting the matrix. Setting reset to false is useful for GL_SELECT mode, to combine the pushed matrix with a picking matrix. See QGLViewer::beginSelection() for details.

This method is used by QGLViewer::preDraw() (called before user's QGLViewer::draw() method) to set the GL_PROJECTION matrix according to the viewer's QGLViewer::camera() settings.

Use getProjectionMatrix() to retrieve this matrix. Overload this method if you want your Camera to use an exotic projection matrix. See also loadModelViewMatrix().

Attention:: glMatrixMode is set to GL_PROJECTION.; If you use several OpenGL contexts and bypass the Qt main refresh loop, you should call QGLWidget::makeCurrent() before this method in order to activate the right OpenGL context.

Definition at line 432 of file camera.cpp.

void Camera::loadProjectionMatrixStereo ( bool leftBuffer = true ) const [virtual]

Same as loadProjectionMatrix() but for a stereo setup.

Only the Camera::PERSPECTIVE type() is supported for stereo mode. See QGLViewer::setStereoDisplay().

Uses focusDistance(), IODistance(), and physicalScreenWidth() to compute cameras offset and asymmetric frustums.

When leftBuffer is true, computes the projection matrix associated to the left eye (right eye otherwise). See also loadModelViewMatrixStereo().

See the stereoViewer and the anaglyph examples for an illustration.

To retrieve this matrix, use a code like:

 glMatrixMode(GL_PROJECTION);
 glPushMatrix();
 loadProjectionMatrixStereo(left_or_right);
 glGetFloatv(GL_PROJECTION_MATRIX, m);
 glPopMatrix();

Note that getProjectionMatrix() always returns the mono-vision matrix.

Attention:: glMatrixMode is set to GL_PROJECTION.

Definition at line 505 of file camera.cpp.

void Camera::lookAt ( const Vec & target ) [slot]

Sets the Camera orientation(), so that it looks at point target (defined in the world coordinate system).

The Camera position() is not modified. Simply setViewDirection().

Definition at line 950 of file camera.cpp.

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

Equal operator.

All the parameters of camera are copied. The frame() pointer is not modified, but its Frame::position() and Frame::orientation() are set to those of camera.

Attention:

The Camera screenWidth() and screenHeight() are set to those of camera. If your Camera is associated with a QGLViewer, you should update these value after the call to this method:

 *(camera()) = otherCamera;
 camera()->setScreenWidthAndHeight(width(), height());

The same applies to sceneCenter() and sceneRadius(), if needed.

Definition at line 123 of file camera.cpp.

Quaternion qglviewer::Camera::orientation ( ) const [inline]

Returns the Camera orientation, defined in the world coordinate system.

Actually returns frame()->orientation(). Use setOrientation(), setUpVector() or lookAt() to set the Camera orientation.

Definition at line 151 of file camera.h.

float qglviewer::Camera::physicalDistanceToScreen ( ) const [inline]

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);

Definition at line 493 of file camera.h.

float qglviewer::Camera::physicalScreenWidth ( ) const [inline]

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().

Definition at line 499 of file camera.h.

float Camera::pixelGLRatio ( const Vec & position ) const

Returns the ratio between pixel and OpenGL units at position.

A line of n * pixelGLRatio() OpenGL units, located at position in the world coordinates system, will be projected with a length of n pixels on screen.

Use this method to scale objects so that they have a constant pixel size on screen. The following code will draw a 20 pixel line, starting at sceneCenter() and always directed along the screen vertical direction:

 glBegin(GL_LINES);
 glVertex3fv(sceneCenter());
 glVertex3fv(sceneCenter() + 20 * pixelGLRatio(sceneCenter()) * camera()->upVector());
 glEnd();

Definition at line 761 of file camera.cpp.

void Camera::playPath ( int i ) [virtual, slot]

Makes the Camera follow the path of keyFrameInterpolator() number i.

If the interpolation is started, it stops it instead.

This method silently ignores undefined (empty) paths (see keyFrameInterpolator()).

The default keyboard shortcut for this method is F[1-12]. Set QGLViewer::pathKey() and QGLViewer::playPathKeyboardModifiers().

Definition at line 1578 of file camera.cpp.

Vec Camera::pointUnderPixel	(	const QPoint &	pixel,
		bool &	found
	)		const

Returns the coordinates of the 3D point located at pixel (x,y) on screen.

Calls a glReadPixel to get the pixel depth and applies an unprojectedCoordinatesOf() to the result. found indicates whether a point was found or not (i.e. background pixel, result's depth is zFar() in that case).

x and y are expressed in pixel units with an origin in the upper left corner. Use screenHeight() - y to convert to OpenGL standard.

Attention:: This method assumes that a GL context is available, and that its content was drawn using the Camera (i.e. using its projection and modelview matrices). This method hence cannot be used for offscreen Camera computations. Use cameraCoordinatesOf() and worldCoordinatesOf() to perform similar operations in that case.

Note:: The precision of the z-Buffer highly depends on how the zNear() and zFar() values are fitted to your scene. Loose boundaries will result in imprecision along the viewing direction.

Definition at line 913 of file camera.cpp.

Vec qglviewer::Camera::position ( ) const [inline]

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 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.

Definition at line 114 of file camera.h.

Vec Camera::projectedCoordinatesOf	(	const Vec &	src,
		const Frame *	frame = `NULL`
	)		const

Returns the screen projected coordinates of a point src defined in the frame coordinate system.

When frame in NULL (default), src is expressed in the world coordinate system.

The x and y coordinates of the returned Vec are expressed in pixel, (0,0) being the upper left corner of the window. The z coordinate ranges between 0.0 (near plane) and 1.0 (excluded, far plane). See the gluProject man page for details.

unprojectedCoordinatesOf() performs the inverse transformation.

See the screenCoordSystem example.

This method only uses the intrinsic Camera parameters (see getModelViewMatrix(), getProjectionMatrix() and getViewport()) and is completely independent of the OpenGL GL_MODELVIEW, GL_PROJECTION and viewport matrices. You can hence define a virtual Camera and use this method to compute projections out of a classical rendering context.

Attention:: However, if your Camera is not attached to a QGLViewer (used for offscreen computations for instance), make sure the Camera matrices are updated before calling this method. Call computeModelViewMatrix() and computeProjectionMatrix() to do so.

If you call this method several times with no change in the matrices, consider precomputing the projection times modelview matrix to save computation time if required (P x M in the gluProject man page).

Here is the code corresponding to what this method does (kindly submitted by Robert W. Kuhn) :

 Vec project(Vec point)
 {
        GLint    Viewport[4];
        GLdouble Projection[16], Modelview[16]; 
        GLdouble matrix[16];

        // Precomputation begin
        glGetIntegerv(GL_VIEWPORT         , Viewport);
        glGetDoublev (GL_MODELVIEW_MATRIX , Modelview);
        glGetDoublev (GL_PROJECTION_MATRIX, Projection); 

        for (unsigned short m=0; m<4; ++m)
        {
                for (unsigned short l=0; l<4; ++l)
                {
                        double sum = 0.0;
                        for (unsigned short k=0; k<4; ++k)
                                sum += Projection[l+4*k]*Modelview[k+4*m];
                        matrix[l+4*m] = sum;
                }
        }
        // Precomputation end
                
        GLdouble v[4], vs[4];
        v[0]=point[0]; v[1]=point[1]; v[2]=point[2]; v[3]=1.0;

        vs[0]=matrix[0 ]*v[0] + matrix[4 ]*v[1] + matrix[8 ]*v[2] + matrix[12 ]*v[3];
        vs[1]=matrix[1 ]*v[0] + matrix[5 ]*v[1] + matrix[9 ]*v[2] + matrix[13 ]*v[3];
        vs[2]=matrix[2 ]*v[0] + matrix[6 ]*v[1] + matrix[10]*v[2] + matrix[14 ]*v[3];
        vs[3]=matrix[3 ]*v[0] + matrix[7 ]*v[1] + matrix[11]*v[2] + matrix[15 ]*v[3];

        vs[0] /= vs[3];
        vs[1] /= vs[3];
        vs[2] /= vs[3];

        vs[0] = vs[0] * 0.5 + 0.5;
        vs[1] = vs[1] * 0.5 + 0.5;
        vs[2] = vs[2] * 0.5 + 0.5;

        vs[0] = vs[0] * Viewport[2] + Viewport[0];
        vs[1] = vs[1] * Viewport[3] + Viewport[1];

        return Vec(vs[0], Viewport[3]-vs[1], vs[2]);    
  }

Definition at line 1441 of file camera.cpp.

void Camera::resetPath ( int i ) [virtual, slot]

Resets the path of the keyFrameInterpolator() number i.

If this path is not being played (see playPath() and KeyFrameInterpolator::interpolationIsStarted()), resets it to its starting position (see KeyFrameInterpolator::resetInterpolation()). If the path is played, simply stops interpolation.

Definition at line 1593 of file camera.cpp.

Vec qglviewer::Camera::revolveAroundPoint ( ) const [inline]

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.

Definition at line 361 of file camera.h.

Vec qglviewer::Camera::rightVector ( ) const [inline]

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)).

Definition at line 142 of file camera.h.

Vec qglviewer::Camera::sceneCenter ( ) const [inline]

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().

Definition at line 338 of file camera.h.

float qglviewer::Camera::sceneRadius ( ) const [inline]

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.