A perspective or orthographic camera. More...

#include <QGLViewer/camera.h>

Inheritance diagram for qglviewer::Camera:

Public Types
enum	Type { PERSPECTIVE, ORTHOGRAPHIC }

Public Member Functions
	Camera ()

	Camera (const Camera &camera)

Camera &	operator= (const Camera &camera)

virtual	~Camera ()

Private Slots
void	onFrameModified ()

Private Attributes
qreal	fieldOfView_

qreal	focusDistance_

ManipulatedCameraFrame *	frame_

KeyFrameInterpolator *	interpolationKfi_

qreal	IODistance_

QMap< unsigned int, KeyFrameInterpolator * >	kfi_

GLdouble	modelViewMatrix_ [16]

bool	modelViewMatrixIsUpToDate_

qreal	orthoCoef_

qreal	physicalScreenWidth_

GLdouble	projectionMatrix_ [16]

bool	projectionMatrixIsUpToDate_

Vec	sceneCenter_

qreal	sceneRadius_

int	screenHeight_

int	screenWidth_

Type	type_

qreal	zClippingCoef_

qreal	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 qreal matrix[12])

void	setPosition (const Vec &pos)

void	setOrientation (const Quaternion &q)

void	setOrientation (qreal theta, qreal 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, qreal 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, qreal duration)

Frustum
Type	type () const

qreal	fieldOfView () const

qreal	horizontalFieldOfView () const

qreal	aspectRatio () const

int	screenWidth () const

int	screenHeight () const

void	getViewport (GLint viewport[4]) const

qreal	pixelGLRatio (const Vec &position) const

qreal	zNearCoefficient () const

qreal	zClippingCoefficient () const

virtual qreal	zNear () const

virtual qreal	zFar () const

virtual void	getOrthoWidthHeight (GLdouble &halfWidth, GLdouble &halfHeight) const

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

void	setType (Type type)

void	setFieldOfView (qreal fov)

void	setHorizontalFieldOfView (qreal hfov)

void	setFOVToFitScene ()

void	setAspectRatio (qreal aspect)

void	setScreenWidthAndHeight (int width, int height)

void	setZNearCoefficient (qreal coef)

void	setZClippingCoefficient (qreal coef)

Scene radius and center
qreal	sceneRadius () const

Vec	sceneCenter () const

qreal	distanceToSceneCenter () const

void	setSceneRadius (qreal radius)

void	setSceneCenter (const Vec &center)

bool	setSceneCenterFromPixel (const QPoint &pixel)

void	setSceneBoundingBox (const Vec &min, const Vec &max)

Pivot Point
Vec	pivotPoint () const

Vec	revolveAroundPoint () const

void	setPivotPoint (const Vec &point)

bool	setPivotPointFromPixel (const QPoint &pixel)

void	setRevolveAroundPoint (const Vec &point)

bool	setRevolveAroundPointFromPixel (const QPoint &pixel)

Associated frame
ManipulatedCameraFrame *	frame () const

void	setFrame (ManipulatedCameraFrame *const mcf)

KeyFramed paths
KeyFrameInterpolator *	keyFrameInterpolator (unsigned int i) const

void	setKeyFrameInterpolator (unsigned int i, KeyFrameInterpolator *const kfi)

virtual void	addKeyFrameToPath (unsigned int i)

virtual void	playPath (unsigned int i)

virtual void	deletePath (unsigned int i)

virtual void	resetPath (unsigned 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 (GLfloat m[16]) const

void	getProjectionMatrix (GLdouble m[16]) const

void	getModelViewMatrix (GLfloat m[16]) const

void	getModelViewMatrix (GLdouble m[16]) const

void	getModelViewProjectionMatrix (GLfloat m[16]) const

void	getModelViewProjectionMatrix (GLdouble m[16]) const

Drawing
virtual void	draw (bool drawFarPlane=true, qreal scale=1.0) const

static void	drawCamera (qreal scale=1.0, qreal aspectRatio=1.33, qreal fieldOfView=qreal(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 qreal src[3], qreal res[3]) const

void	getWorldCoordinatesOf (const qreal src[3], qreal 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 qreal src[3], qreal res[3], const Frame *frame=NULL) const

void	getUnprojectedCoordinatesOf (const qreal src[3], qreal 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
qreal	flySpeed () const

void	setFlySpeed (qreal speed)

Stereo parameters
qreal	IODistance () const

qreal	physicalDistanceToScreen () const

qreal	physicalScreenWidth () const

qreal	focusDistance () const

void	setIODistance (qreal distance)

void	setPhysicalDistanceToScreen (qreal distance)

void	setPhysicalScreenWidth (qreal width)

void	setFocusDistance (qreal 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 pivotPoint(). 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 84 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()...) are affected by this Type.

Enumerator
PERSPECTIVE
ORTHOGRAPHIC

Definition at line 105 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 38 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 86 of file camera.cpp.

Camera::Camera ( const Camera & camera )

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

Definition at line 94 of file camera.cpp.

Member Function Documentation

void Camera::addKeyFrameToPath ( unsigned int i )

virtualslot

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::update() slot (see setKeyFrameInterpolator()).

Definition at line 1710 of file camera.cpp.

qreal 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 185 of file camera.h.

Vec Camera::cameraCoordinatesOf ( const Vec & src ) const

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 1248 of file camera.cpp.

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 997 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 400 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 350 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 1940 of file camera.cpp.

void Camera::deletePath ( unsigned int i )

virtualslot

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(update()));

camera()->deletePath(i);

Definition at line 1762 of file camera.cpp.

qreal 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 303 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 1811 of file camera.cpp.

void Camera::draw	(	bool	drawFarPlane = `true`,
		qreal	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 1993 of file camera.cpp.

void Camera::drawAllPaths ( )

virtualslot

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 1778 of file camera.cpp.

void Camera::drawCamera	(	qreal	scale = `1.0`,
		qreal	aspectRatio = `1.33`,
		qreal	fieldOfView = `qreal(M_PI)/4.0`
	)

static

This method has been deprecated in libQGLViewer version 2.2.0

Definition at line 1967 of file camera.cpp.

qreal 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 170 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 1044 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 1058 of file camera.cpp.

void Camera::fitSphere	(	const Vec &	center,
		qreal	radius
	)

slot

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

The Camera is simply translated to center the sphere in the screen and make it fit the frustum. 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 1020 of file camera.cpp.

qreal Camera::flySpeed ( ) const

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 1263 of file camera.cpp.

qreal 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 452 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 334 of file camera.h.

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

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

Definition at line 1482 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 2121 of file camera.cpp.

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

Overloaded getModelViewMatrix(GLdouble m[16]) method using a GLfloat array instead.

Definition at line 662 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 may not be 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 (using glTranslate, glRotate... or similar methods), 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 651 of file camera.cpp.

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

Overloaded getModelViewProjectionMatrix(GLdouble m[16]) method using a GLfloat array instead.

Definition at line 693 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 673 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 pivotPoint(). 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 324 of file camera.cpp.

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

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

Definition at line 1644 of file camera.cpp.

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

Overloaded getProjectionMatrix(GLdouble m[16]) method using a GLfloat array instead.

Definition at line 629 of file camera.cpp.

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

Fills m with the Camera projection matrix values.

Based on computeProjectionMatrix() to make sure the Camera projection matrix is up to date.

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 621 of file camera.cpp.

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

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

Definition at line 1652 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 1502 of file camera.cpp.

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

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

Definition at line 1490 of file camera.cpp.

qreal 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 179 of file camera.h.

void Camera::initFromDOMElement ( const QDomElement & element )

virtualslot

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 1869 of file camera.cpp.

void Camera::interpolateTo	(	const Frame &	fr,
		qreal	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 942 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 913 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 875 of file camera.cpp.

qreal 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 425 of file camera.h.

KeyFrameInterpolator * Camera::keyFrameInterpolator ( unsigned 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 1664 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 500 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 591 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 463 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);
glGetDoublev(GL_PROJECTION_MATRIX, m);
glPopMatrix();

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

Attention: glMatrixMode is set to GL_PROJECTION.

Definition at line 536 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 1008 of file camera.cpp.

void Camera::onFrameModified ( )

privateslot

Definition at line 2206 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 124 of file camera.cpp.

Quaternion Camera::orientation ( ) const

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 1237 of file camera.cpp.

qreal 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 434 of file camera.h.

qreal 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 440 of file camera.h.

Vec Camera::pivotPoint ( ) const

The point the Camera pivots 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 1275 of file camera.cpp.

qreal 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 819 of file camera.cpp.

void Camera::playPath ( unsigned int i )

virtualslot

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 1726 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 971 of file camera.cpp.

Vec Camera::position ( ) const

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 1200 of file camera.cpp.

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)
        {
                qreal 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 1584 of file camera.cpp.

void Camera::resetPath ( unsigned int i )

virtualslot

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 1741 of file camera.cpp.

Vec Camera::revolveAroundPoint ( ) const

Definition at line 763 of file camera.cpp.

Vec Camera::rightVector ( ) const

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 1228 of file camera.cpp.

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 calls this method (resp. setSceneCenter()) on its associated QGLViewer::camera().

Definition at line 297 of file camera.h.

qreal 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.

Friends And Related Function Documentation

friend class ::QGLViewer

friend

Definition at line 87 of file camera.h.

Member Data Documentation

qreal qglviewer::Camera::fieldOfView_

private

Definition at line 488 of file camera.h.

qreal qglviewer::Camera::focusDistance_

private

Definition at line 502 of file camera.h.

ManipulatedCameraFrame* qglviewer::Camera::frame_

private

Definition at line 484 of file camera.h.

KeyFrameInterpolator* qglviewer::Camera::interpolationKfi_

private

Definition at line 507 of file camera.h.

qreal qglviewer::Camera::IODistance_

private

Definition at line 501 of file camera.h.

QMap<unsigned int, KeyFrameInterpolator*> qglviewer::Camera::kfi_

private

Definition at line 506 of file camera.h.

GLdouble qglviewer::Camera::modelViewMatrix_[16]

mutableprivate

Definition at line 495 of file camera.h.

bool qglviewer::Camera::modelViewMatrixIsUpToDate_

mutableprivate

Definition at line 496 of file camera.h.

qreal qglviewer::Camera::orthoCoef_

private

Definition at line 493 of file camera.h.

qreal qglviewer::Camera::physicalScreenWidth_

private

Definition at line 503 of file camera.h.

GLdouble qglviewer::Camera::projectionMatrix_[16]

mutableprivate

Definition at line 497 of file camera.h.

bool qglviewer::Camera::projectionMatrixIsUpToDate_

mutableprivate

Definition at line 498 of file camera.h.

Vec qglviewer::Camera::sceneCenter_

private

Definition at line 489 of file camera.h.

qreal qglviewer::Camera::sceneRadius_

private

Definition at line 490 of file camera.h.

int qglviewer::Camera::screenHeight_

private

Definition at line 487 of file camera.h.

int qglviewer::Camera::screenWidth_

private

Definition at line 487 of file camera.h.

Type qglviewer::Camera::type_

private

Definition at line 494 of file camera.h.

qreal qglviewer::Camera::zClippingCoef_

private

Definition at line 492 of file camera.h.

qreal qglviewer::Camera::zNearCoef_

private

Definition at line 491 of file camera.h.

The documentation for this class was generated from the following files:

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

Public Types

Public Member Functions

Private Slots

Private Attributes

Friends

Position and orientation

Positioning tools

Frustum

Scene radius and center

Pivot Point

Associated frame

KeyFramed paths

OpenGL matrices

Drawing

World to Camera coordinate systems conversions

2D screen to 3D world coordinate systems conversions

Fly speed

Stereo parameters

XML representation

Detailed Description

Mouse manipulation

Other functionalities

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation