com.openinventor.inventor.viewercomponents

Class SoCameraInteractor

java.lang.Object

com.openinventor.inventor.Inventor

com.openinventor.inventor.viewercomponents.SoCameraInteractor

All Implemented Interfaces:

SafeDisposable

public class SoCameraInteractor
extends Inventor
implements SafeDisposable

Utility class to manipulate a camera. This class provides some useful algorithms to manipulate a camera (translation, rotation, zoom, etc).

This class is not, strictly speaking, a true interactor. It does not respond to input events. However it provides the camera manipulation algorithms you need to build an interactor that provides behavior similar to the Open Inventor viewer classes, for example SoWinExaminerViewer. An interactor could handle system-dependent events or Open Inventor events (using SoEventCallback). It could also be triggered from the user interface (buttons, sliders, etc).

Start by creating an instance of SoCameraInteractor by giving the camera to be manipulated either to the constructor of SoCameraInteractor or to the getNewInstance() method. Then, for example, to provide examinerViewer-like rotation behavior:

• On a mouse button down event, call activateOrbiting().
• On mouse move event, if button is down, call orbit().

To provide the viewer's automatic adjustment of near and far clip planes behavior, call the adjustClippingPlanes() method before each render traversal.

To see an example "viewer" implemented using this class, please see the SceneExaminer class provided as source code in the Open Inventor SDK:

.../source/com/openinventor/inventor/viewercomponents/nodes EXAMPLE

See also:

SceneInteractor, SceneExaminer

Nested Class Summary

Nested classes/interfaces inherited from class com.openinventor.inventor.Inventor

Inventor.ConstructorCommand

Field Summary

Fields inherited from class com.openinventor.inventor.Inventor

VERBOSE_LEVEL, ZeroHandle

Constructor Summary

Constructors

Constructor and Description
SoCameraInteractor(SoCamera camera) Create a SoCameraInteractor for the specified camera.

Method Summary

Modifier and Type	Method and Description
void	activateOrbiting(SbVec2f startPos) Set the starting point for interactive orbiting.
void	activatePanning(SbVec2f initPos, SbViewportRegion vpRegion) Set the starting point for interactive panning.
void	adjustClippingPlanes(SoNode sceneRoot, SbViewportRegion vpRegion) Adjust near and far clipping planes to minimize clipping of objects in the scene.
void	changeViewVolume(float height, float aspect) Change camera's view volume.
boolean	dispose() Explicitly call this method to force object to dispose its unmanaged resources.
void	dolly(float scaleFactor) Dolly - Makes the scene appear larger or smaller.
void	dollyInWindow(SbVec2f topLeftCorner, SbVec2f bottomRightCorner, SbViewportRegion vpRegion) Moves the camera forward or backward along the view vector to view the region defined by the given corners in normalized screen coordinates.
void	dollyWithZoomCenter(SbVec2f centerPos, float scaleFactor, SbViewportRegion vpRegion) Modifies the camera to ajust the view around the specified point.
SoCamera	getCamera() Returns the associated camera.
SbVec3f	getDirectionVector() Returns the direction vector of the camera.
SbVec3f	getFocalPoint() Returns the camera's "focal point", located focalDistance units from the camera position along the view direction vector (defined by the camera's orientation field).
static SoCameraInteractor	getNewInstance(SoCamera camera) Create an instance for the specified camera.
SbVec3f	getViewportCenter() Deprecated. As of Open Inventor 9500 See documentation for more details
boolean	isDisposable() Returns a boolean flag which indicates if it is safe to call SafeDisposable.dispose() on the object.
SbRotation	lookAt(SbVec3f position, SbVec3f target, SbVec3f up) Returns the rotation needed to point a camera at position toward the given target point while keeping the "up" direction of the camera parallel to the specified up vector.
void	orbit(SbRotation rotation) Orbit the camera by the specified rotation.
void	orbit(SbVec2f newPos) Orbit the camera based on offset from the previous screen position.
void	pan(SbVec2f newPos, SbViewportRegion vpRegion) Pan the camera based on offset from starting point.
void	pivot(float angle) Pivot the camera.
void	pointAt(SbVec3f targetPoint) Sets the orientation of the camera so that it points toward the given target point while keeping the "up" direction of the camera parallel to the positive world coordinate y-axis.
boolean	popCamera() Restore saved camera.
SbVec3f	projectToPlane(SbVec2f point, float distFromEye, SbViewportRegion vpRegion) Project specified 2D point on the plane parallel to the near plane that is at distFromEye units from the eye, see also SbViewVolume.getPlanePoint.
SbVec2f	projectToScreen(SbVec3f point, SbViewportRegion vpRegion) Map a 3D point in world coordinates to a 2D point in normalized screen coordinates (0 <= x,y <= 1), see also SbViewVolume.projectToScreen.
void	pushCamera() Save current camera.
void	roll(float angle) Roll the camera.
void	rotate(float angle) Rotate the camera around the center specified by setRotationCenter() and the axis specified by setRotationAxis().
void	rotate(SbRotation rot) Rotate the camera.
void	setOrientation(SbRotation rot) Set the orientation of the camera.
void	setPosition(SbVec2f pos, float distFromEye, SbViewportRegion vpRegion) Move camera to the specified position.
void	setPosition(SbVec3f pos) Move camera to the specified position.
void	setRotationAxis(SbVec3f axis) Set the axis of rotation.
void	setRotationCenter(SbVec3f pos) Set the center of rotation.
void	synchronize(SoCamera camera) Copy field values from the specified camera to the camera of this interactor.
void	tilt(float angle) Tilt the camera.
void	translate(SbVec2f displacement, SbViewportRegion vpRegion) Move camera by the specified 2D displacement.
void	translate(SbVec3f trans) Move camera by the specified 3D displacement.
void	viewAll(SoNode node, SbViewportRegion vpRegion) Move the camera to view the scene defined by the given node.
void	viewAll(SoPath path, SbViewportRegion vpRegion) Move the camera to view the scene defined by the given path.
void	viewAxis(SbVec3f direction, SbVec3f up) Moves and rotates the camera to be aligned with the given direction vector while keeping the up direction of the camera parallel to the specified up vector.
void	viewIn(SbBox3f bbox) Move camera to the center of the specified box.
void	viewIn(SoNode node, SbViewportRegion vpRegion) Move camera to the center of the scene defined by the specified node.
void	viewIn(SoPath path, SbViewportRegion vpRegion) Move camera to the center of the scene defined by the specified path.
void	viewX() Calls viewX((boolean)false).
void	viewX(boolean reverse) NOTE: The camera position is not changed, so the camera may not be looking toward the scene.
void	viewY() Calls viewY((boolean)false).
void	viewY(boolean reverse) Rotate camera to look parallel to the Y axis with +Z up.
void	viewZ() Calls viewZ((boolean)false).
void	viewZ(boolean reverse) Rotate camera to look parallel to the Z axis with +Y up.
void	zoom(float zoom) Zoom - Makes the scene appear larger or smaller.
void	zoomInWindow(SbVec2f topLeftCorner, SbVec2f bottomRightCorner, SbViewportRegion vpRegion) Zooms to the region defined by the given corners in normalized screen coordinates.

Methods inherited from class com.openinventor.inventor.Inventor

getAddress, getNativeResourceHandle, startInternalThreads, stopInternalThreads

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SoCameraInteractor

public SoCameraInteractor(SoCamera camera)

Create a SoCameraInteractor for the specified camera. The camera should be an SoPerspectiveCamera or SoOrthographicCamera object. Create an empty object if camera pointer is NULL or invalid

Method Detail

viewZ

public void viewZ()

Calls viewZ((boolean)false).

viewY

public void viewY()

Calls viewY((boolean)false).

viewX

public void viewX()

Calls viewX((boolean)false).

isDisposable

public boolean isDisposable()

Description copied from interface: SafeDisposable

Returns a boolean flag which indicates if it is safe to call SafeDisposable.dispose() on the object.

Specified by:

isDisposable in interface SafeDisposable

Returns:

true if the object can be disposed in a safe manner

dispose

public boolean dispose()

Description copied from class: Inventor

Explicitly call this method to force object to dispose its unmanaged resources. The object may not be reused in the application code after this call.

Specified by:

dispose in interface SafeDisposable

Overrides:

dispose in class Inventor

Returns:

true if this object native resources were successfully disposed; false if it was already disposed or no native resources has been registered for this object.

setPosition

public void setPosition(SbVec2f pos,
                        float distFromEye,
                        SbViewportRegion vpRegion)

Move camera to the specified position.

Parameters:

pos - new position (2D point in normalized screen coordinates: 0 <= x,y <= 1)

distFromEye - the distance at which the point would be back projected.

vpRegion - the actual viewport region

orbit

public void orbit(SbRotation rotation)

Orbit the camera by the specified rotation. "Orbit" means to rotate the camera around a fixed point in 3D space. The rotation point is specified using the setRotationCenter() method. This method automatically calls the setRotationAxis() method with the axis defined by the SbRotation parameter.

Orbit is often used in an "examiner" type of viewer to allow the user to rotate the camera around a point of interest in the scene. Orbit based on mouse or touch events can be implemented using the orbit() method. This method can be used, for example, to animate the camera to a new viewpoint. To implement orbit around the camera's "focal point", call setRotationCenter() with the value returned from getFocalPoint().

Parameters:

rotation - Incremental rotation, i.e. this rotation is multiplied with the current camera orientation.

orbit

public void orbit(SbVec2f newPos)

Orbit the camera based on offset from the previous screen position. This method can be used to implement an interactive orbit operation in response to mouse move or touch events. The activateOrbiting() method should be called at the start of the operation. This method uses an SbSphereSheetProjector to compute a rotation value based on the specified point and the previously specified point.

Parameters:

newPos - new position, 2D point in normalized screen coordinates (0 <= x,y <= 1). Typically this value is obtained from the SoEvent method getNormalizedPosition().

pushCamera

public void pushCamera()

Save current camera. The values of the camera fields are saved and can be restored by calling popCamera().

setPosition

public void setPosition(SbVec3f pos)

Move camera to the specified position.

Parameters:

pos - new position in world coordinates

pan

public void pan(SbVec2f newPos,
                SbViewportRegion vpRegion)

Pan the camera based on offset from starting point. This method can be used to implement an interactive panning operation in response to move move or touch events. The activatePanning() method should be called at the start of the operation.

Parameters:

newPos - new position in normalized screen coordinates (0 <= x,y <= 1). Typically this value is obtained from the SoEvent method getNormalizedPosition().

vpRegion - the actual viewport region

pointAt

public void pointAt(SbVec3f targetPoint)

Sets the orientation of the camera so that it points toward the given target point while keeping the "up" direction of the camera parallel to the positive world coordinate y-axis. If this is not possible, it uses the positive z-axis as "up". Equivalent to calling the SoCamera method pointAt().

Parameters:

targetPoint - target point

translate

public void translate(SbVec2f displacement,
                      SbViewportRegion vpRegion)

Move camera by the specified 2D displacement.

Parameters:

displacement - 2D displacement in normalized screen coordinates: 0 <= x,y <= 1

vpRegion - the actual viewport region

translate

public void translate(SbVec3f trans)

Move camera by the specified 3D displacement.

Parameters:

trans - translation value in world coordinates

activateOrbiting

public void activateOrbiting(SbVec2f startPos)

Set the starting point for interactive orbiting. This method should be called when starting an interaction. Typically this is triggered by a mouse button or touch event. On subsequent mouse move or touch events, call the orbit() method with the new cursor or touch position.

Orbit is often used in an "examiner" type of viewer to allow the user to rotate the camera around a point of interest in the scene. To implement orbit around the camera's "focal point", call setRotationCenter() with the value returned from getFocalPoint().

Parameters:

startPos - starting position, 2D point in normalized screen coordinates (0 <= x,y <= 1). Typically this value is obtained from the SoEvent method getNormalizedPosition().

getFocalPoint

public SbVec3f getFocalPoint()

Returns the camera's "focal point", located focalDistance units from the camera position along the view direction vector (defined by the camera's orientation field).

This is the reference point for some algorithms. For example, orbit() is often used in an "examiner" type of viewer to allow the user to rotate the camera around a point of interest in the scene. To implement orbit around the camera's focal point, call the setRotationCenter() method with the focal point before calling the orbit() method.

Returns:

focal point in world coordinates

dolly

public void dolly(float scaleFactor)

Dolly - Makes the scene appear larger or smaller. For a perspective camera, moves the camera forward or backward along the view vector (details below). For an orthographic camera, changes the height field to give a similar visual effect (moving an orthographic camera forward and backward has no visual effect). This is the preferred way to implement the visual effect of "zooming" in and out for a perspective camera. For a perspective camera, dolly means the same thing it means for a camera on a movie set.

Note: 'scaleFactor' is the inverse of what you might expect. To make the scene appear 2X larger, specify a scaleFactor of 0.5. This is because scaleFactor multiplies the camera 'focalDistance' or 'height'.

• Perspective camera: The camera has a "focal point" located focalDistance units from the camera position along the view direction vector ( orientation). Unlike a real camera, neither focal point nor focal distance has effect on the appearance of the image. The focal point is just a reference point for some algorithms. You can think of it as the "look at" point. The dolly() method computes a scale factor from the 'delta' parameter. A new "focal distance" is computed as the current value of the camera's focalDistance field multiplied by this scale factor. Then the camera's position field is modified so the camera is the new focal distance away from the focal point.
• Orthographic camera: The dolly() method computes a scale factor from the 'delta' parameter and multiplies the camera's height field by this scale factor.

changeViewVolume

public void changeViewVolume(float height,
                             float aspect)

Change camera's view volume. Allows changing the view volume height and width with a single call. For a perspective camera, the height parameter is heightAngle in radians. For an orthographic camera, the height parameter is height in world coordinates.

Parameters:

height - new camera height or heightAngle

aspect - new camera aspect ratio

zoom

public void zoom(float zoom)

Zoom - Makes the scene appear larger or smaller. Sets the camera's heightAngle field (for a perspective camera) or height field (for an orthographic camera) to the specified value. For a perspective camera, the value is in radians and the default is 0.785398. For an orthographic camera the value is in World Coordinates and the default is 2.

Conceptually, zoom means approximately the same thing as it does for a real camera - changing the "focal length" of the lens. Making the heightAngle (or height) larger corresponds to using a wide-angle lens, so the scene appears smaller. Making the heightAngle (or height) smaller corresponds to using a telephoto lens, so the scene appears larger.

NOTE: For a perspective camera, we strongly recommend implementing the visual effect of "zoom" by moving the camera closer to, or farther away from, the scene (see dolly()). Very small and very large values of heightAngle can produce undesirable results.

Parameters:

zoom - new zoom value

viewY

public void viewY(boolean reverse)

Rotate camera to look parallel to the Y axis with +Z up. NOTE: The camera position is not changed, so the camera may not be looking toward the scene. Calling viewAll() will move the camera so that the scene is visible again.

Parameters:

reverse - If false, rotate to look in the -Y direction, else in +Y direction.

getViewportCenter

@Deprecated
public SbVec3f getViewportCenter()

Deprecated. As of Open Inventor 9500 See documentation for more details

Returns the viewport center. On other words, returns the camera's "focal point", located focalDistance units from the camera position along the view direction vector ( orientation).

Returns:

center in world coordinatesDeprecated since Open Inventor 9500
Use getFocalPoint() instead.

popCamera

public boolean popCamera()

Restore saved camera. The values of the camera fields are restored to the last pushed values. Returns true if successful, false if the vector of pushed cameras is empty.

synchronize

public void synchronize(SoCamera camera)

Copy field values from the specified camera to the camera of this interactor. If the two cameras are not the same type, common fields are copied and the height or heightAngle field is computed.

getNewInstance

public static SoCameraInteractor getNewInstance(SoCamera camera)

Create an instance for the specified camera. The camera should be an SoPerspectiveCamera or SoOrthographicCamera object. Returns null if the camera parameter is null.

getCamera

public SoCamera getCamera()

Returns the associated camera.

viewAll

public void viewAll(SoPath path,
                    SbViewportRegion vpRegion)

Move the camera to view the scene defined by the given path. Equivalent to calling the SoCamera method viewAll(). The camera position is changed, but not the orientation.

• Orthographic camera: the height field is changed.
• Perspective camera: the heightAngle field is NOT changed.

setRotationAxis

public void setRotationAxis(SbVec3f axis)

Set the axis of rotation. Default is (0, 0, 0). This vector is used by the rotate(float) method.

Parameters:

axis - new rotations axis

viewIn

public void viewIn(SoNode node,
                   SbViewportRegion vpRegion)

Move camera to the center of the scene defined by the specified node. Compute the bounding box of the scene and move the camera to the center of this box. The near and far clipping planes will be adjusted to see the inside of the box.

Parameters:

node - root node of the scene

vpRegion - the actual viewport region

setOrientation

public void setOrientation(SbRotation rot)

Set the orientation of the camera. Replaces any previous rotations applied to the camera. Camera position does not change.

Parameters:

rot - new orientation

viewAll

public void viewAll(SoNode node,
                    SbViewportRegion vpRegion)

Move the camera to view the scene defined by the given node. Equivalent to calling the SoCamera method viewAll(). The camera position is changed, but not the orientation.

• Orthographic camera: the height field is changed.
• Perspective camera: the heightAngle field is NOT changed.

setRotationCenter

public void setRotationCenter(SbVec3f pos)

Set the center of rotation. Default is (0, 0, 0). This position is used by the rotate(float) and orbit() methods.

Parameters:

pos - position in world coordinates

viewIn

public void viewIn(SbBox3f bbox)

Move camera to the center of the specified box. The near and far clipping planes will be adjusted to see the inside of the box. If the box is empty, nothing happens.

viewX

public void viewX(boolean reverse)

NOTE: The camera position is not changed, so the camera may not be looking toward the scene. Calling viewAll() will move the camera so that the scene is visible again.

Parameters:

reverse - If false, rotate to look in the -X direction, else in +X direction.

viewZ

public void viewZ(boolean reverse)

Rotate camera to look parallel to the Z axis with +Y up. NOTE: The camera position is not changed, so the camera may not be looking toward the scene. Calling viewAll() will move the camera so that the scene is visible again.

Parameters:

reverse - If false, rotate to look in the -Z direction, else in +Z direction.

rotate

public void rotate(float angle)

Rotate the camera around the center specified by setRotationCenter() and the axis specified by setRotationAxis(). The default rotation axis is (0,0,0), so calling this method will not have any visible effect until a rotation axis is set. The rotation axis is automatically set by some methods, e.g. orbit().

Parameters:

angle - angle in radians

viewIn

public void viewIn(SoPath path,
                   SbViewportRegion vpRegion)

Move camera to the center of the scene defined by the specified path. Compute the bounding box of the scene and move the camera to the center of this box. The near and far clipping planes will be adjusted to see the inside of the box.

Parameters:

path - path to the scene

vpRegion - the actual viewport region

viewAxis

public void viewAxis(SbVec3f direction,
                     SbVec3f up)

Moves and rotates the camera to be aligned with the given direction vector while keeping the up direction of the camera parallel to the specified up vector. The camera position and orientation are changed to look at the point of interest, but the focalDistance is not changed.

Parameters:

direction - The new view direction vector: this is the vector from the camera's position to the target point. Any future call to the method getDirectionVector() will return the same vector.

up - The new up direction vector

projectToPlane

public SbVec3f projectToPlane(SbVec2f point,
                              float distFromEye,
                              SbViewportRegion vpRegion)

Project specified 2D point on the plane parallel to the near plane that is at distFromEye units from the eye, see also SbViewVolume.getPlanePoint.

Parameters:

point - point to project in normalized screen coordinates (0 <= x,y <= 1)

distFromEye - the distance at which the point would be back projected

vpRegion - the actual viewport region

Returns:

projected point in world coordinates

getDirectionVector

public SbVec3f getDirectionVector()

Returns the direction vector of the camera.

dollyInWindow

public void dollyInWindow(SbVec2f topLeftCorner,
                          SbVec2f bottomRightCorner,
                          SbViewportRegion vpRegion)

Moves the camera forward or backward along the view vector to view the region defined by the given corners in normalized screen coordinates.

• Perspective camera: The visual result is similar to zoomInWindow(), but this method changes the camera position (closer or farther away) and focalDisance fields instead of changing the heightAngle. This is the recommended method when using a perspective camera, because it avoids the limitations of very small or very large heightAngle values.
• Orthographic camera: This method does nothing because moving the camera closer or farther away does not change the visual result.

roll

public void roll(float angle)

Roll the camera. Incremental in-place rotation around the view direction vector (camera's local Z axis). Rotations are cumulative. Camera position does not change. Positive values roll the camera counter-clockwise.

Parameters:

angle - angle in radians

activatePanning

public void activatePanning(SbVec2f initPos,
                            SbViewportRegion vpRegion)

Set the starting point for interactive panning. This method should be called when starting an interaction. Typically this is triggered by a mouse button or touch event. On subsequent mouse move or touch events, call the pan() method with the new cursor or touch position.

Parameters:

initPos - initial position in normalized screen coordinates (0 <= x,y <= 1). Typically this value is obtained from the SoEvent method getNormalizedPosition().

vpRegion - the actual viewport region

lookAt

public SbRotation lookAt(SbVec3f position,
                         SbVec3f target,
                         SbVec3f up)

Returns the rotation needed to point a camera at position toward the given target point while keeping the "up" direction of the camera parallel to the specified up vector. This method does NOT modify the camera node. Set the returned rotation in the camera's orientation field.

Parameters:

position - of the camera

target - position of the target

up - up vector of the camera

dollyWithZoomCenter

public void dollyWithZoomCenter(SbVec2f centerPos,
                                float scaleFactor,
                                SbViewportRegion vpRegion)

Modifies the camera to ajust the view around the specified point. The algorithm is the same as the dolly() method (for a perspective camera the position field is changed, for an orthographic camera the height field is changed) and the delta parameter is used the same way.

Parameters:

centerPos - zoom center in normalized screen coordinates (0 <= x,y <= 1). Typically this value is obtained from the SoEvent method getNormalizedPosition().

scaleFactor - zoom scale

vpRegion - the actual viewport region

tilt

public void tilt(float angle)

Tilt the camera. Incremental in-place rotation up/down (around the camera's local X axis). Rotations are cumulative. Camera position does not change. Positive values tilt the camera up.

Parameters:

angle - angle in radians

projectToScreen

public SbVec2f projectToScreen(SbVec3f point,
                               SbViewportRegion vpRegion)

Map a 3D point in world coordinates to a 2D point in normalized screen coordinates (0 <= x,y <= 1), see also SbViewVolume.projectToScreen.

Parameters:

point - point to project in world coordinates

vpRegion - the actual viewport region

Returns:

2D point in normalized screen coordinates (0 <= x,y <= 1)

rotate

public void rotate(SbRotation rot)

Rotate the camera. Incremental in-place rotation. Rotations are cumulative. Camera position does not change (rotationCenter and rotationAxis do not apply).

Parameters:

rot - new rotation

zoomInWindow

public void zoomInWindow(SbVec2f topLeftCorner,
                         SbVec2f bottomRightCorner,
                         SbViewportRegion vpRegion)

Zooms to the region defined by the given corners in normalized screen coordinates.

• Perspective camera: This method modifies the heightAngle field.
  Modifying the heightAngle field changes the projection, similar to changing the focal length of a camera. Making the heightAngle very small or very large may cause rendering artifacts. Therefore the dollyInWindow method is recommended when using a perspective camera.
• Orthographic camera: This method modifies the height field.

Parameters:

topLeftCorner - top left corner in normalized screen coordinates (0 <= x,y <= 1)

bottomRightCorner - bottom right corner in normalized screen coordinates (0 <= x,y <= 1)

vpRegion - the actual viewport region

pivot

public void pivot(float angle)

Pivot the camera. Incremental in-place rotation left/right (around the camera's up vector, i.e. local Y axis). Rotations are cumulative. Camera position does not change. Positive values pivot the camera left.

Parameters:

angle - angle in radians

adjustClippingPlanes

public void adjustClippingPlanes(SoNode sceneRoot,
                                 SbViewportRegion vpRegion)

Adjust near and far clipping planes to minimize clipping of objects in the scene. Equivalent to the auto clip planes feature in the viewer classes. Typically called before each render traversal.