NAME
SoRayPickAction -
The SoRayPickAction class does ray intersection with scene graphs.
For interaction with the scene graph geometry, it is necessary to be
able to do intersection testing for rays. This functionality is
provided by the SoRayPickAction class.
SYNOPSIS
#include <Inventor/actions/SoRayPickAction.h>
Inherits SoPickAction.
Public Member Functions
SoRayPickAction (const SbViewportRegion &viewportregion)
virtual ~SoRayPickAction ()
void setPoint (const SbVec2s &viewportPoint)
void setNormalizedPoint (const SbVec2f &normpoint)
void setRadius (const float radiusinpixels)
void setRay (const SbVec3f &start, const SbVec3f &direction, float
neardistance=-1.0, float fardistance=-1.0)
void setPickAll (const SbBool flag)
SbBool isPickAll (void) const
const SoPickedPointList & getPickedPointList (void) const
SoPickedPoint * getPickedPoint (const int index=0) const
void computeWorldSpaceRay (void)
SbBool hasWorldSpaceRay (void) const
void setObjectSpace (void)
void setObjectSpace (const SbMatrix &matrix)
SbBool intersect (const SbVec3f &v0, const SbVec3f &v1, const SbVec3f
&v2, SbVec3f &intersection, SbVec3f &barycentric, SbBool &front)
const
SbBool intersect (const SbVec3f &v0, const SbVec3f &v1, SbVec3f
&intersection) const
SbBool intersect (const SbVec3f &point) const
SbBool intersect (const SbBox3f &box, const SbBool usefullviewvolume=1)
SbBool intersect (const SbBox3f &box, SbVec3f &intersection, const
SbBool usefullviewvolume=1)
const SbViewVolume & getViewVolume (void)
const SbLine & getLine (void)
SbBool isBetweenPlanes (const SbVec3f &intersection) const
SoPickedPoint * addIntersection (const SbVec3f &objectspacepoint,
SbBool frontpick=1)
void reset (void)
Static Public Member Functions
static void initClass (void)
Protected Member Functions
virtual void beginTraversal (SoNode *node)
Detailed Description
The SoRayPickAction class does ray intersection with scene graphs.
For interaction with the scene graph geometry, it is necessary to be
able to do intersection testing for rays. This functionality is
provided by the SoRayPickAction class.
SoRayPickAction can be used to pass arbitrary rays through the scene
for intersection detections, by using the setRay() method.
Because a very common operation is to check for intersections along the
ray from the mousecursor upon mouseclicks, it also contains convenience
methods for setting up a ray from the near plane to the far plane from
the 2D mousecursor coordinates. See the setPoint() and
setNormalizedPoint() methods. A simple usage example for this case is
presented below.
Note that one common mistake when using a raypick action to intersect
from a point under the mousecursor after a mouseclick is that one tries
to apply it to a scenegraph that does not contain a camera explicitly
set up by the application programmer. Without a camera as part of the
traversal, the raypick action does not know which view volume to send
the ray through.
In this regard, be aware that the getSceneGraph() call in the
So*-libraries’ viewer classes will return the root of the user-supplied
scenegraph, not the ’real’ internal scenegraph root used by the viewer
(which should always contain a camera node). So raypicks done from the
application code will fail when doing this:
// initializing viewer scenegraph
SoSeparator * root = new SoSeparator;
root->ref();
SoEventCallback * ecb = new SoEventCallback;
ecb->addEventCallback(SoMouseButtonEvent::getClassTypeId(), event_cb, viewer);
root->addChild(ecb);
root->addChild(new SoCone);
viewer->setSceneGraph( root );
// -- [snip] -------------------------
// attempting raypick in the event_cb() callback method
SoRayPickAction rp( viewer->getViewportRegion() );
rp.setPoint(mouseevent->getPosition());
rp.apply(viewer->getSceneGraph());
// BUG: results will not be what you expected, as no camera was
// part of the ’user’s scenegraph’
While this is the correct way to do it:
// initializing viewer scenegraph
SoSeparator * root = new SoSeparator;
root->ref();
// Need to set up our own camera in the ’user scenegraph’, or else
// the raypick action will fail because the camera is hidden in the
// viewer-specific root of the scenegraph.
SoPerspectiveCamera * pcam = new SoPerspectiveCamera;
root->addChild(pcam);
SoEventCallback * ecb = new SoEventCallback;
ecb->addEventCallback(SoMouseButtonEvent::getClassTypeId(), event_cb, viewer);
root->addChild(ecb);
root->addChild(new SoCone);
viewer->setSceneGraph( root );
pcam->viewAll( root, viewer->getViewportRegion() );
// -- [snip] -------------------------
// attempting raypick in the event_cb() callback method
SoRayPickAction rp( viewer->getViewportRegion() );
rp.setPoint(mouseevent->getPosition());
rp.apply(viewer->getSceneGraph());
Or if you do want the convenience of having the viewer set up a camera
for you implicitly, you can get hold of the root-node of the ’complete’
scenegraph by simply calling:
SoNode * realroot = viewer->getSceneManager()->getSceneGraph();
Constructor & Destructor Documentation
SoRayPickAction::SoRayPickAction (const SbViewportRegion & viewportregion)
Constructor.
Some node types need a viewportregion to know exactly how they are
positioned within the scene. For an in-depth explanation of why the
viewportregion argument is needed, see the documentation of
SoGetBoundingBox::SoGetBoundingBox(const SbViewportRegion &).
SoRayPickAction::~SoRayPickAction (void) [virtual] Destructor, free
temporary resources used by action.
Member Function Documentation
void SoRayPickAction::initClass (void) [static] Initializes the run-time
type system for this class, and sets up the enabled elements and action
method list.
Reimplemented from SoPickAction.
void SoRayPickAction::setPoint (const SbVec2s & viewportpoint) Sets the
viewport-space point. This point is calculated into a line from the
near clipping plane to the far clipping plane, and the intersection ray
follows the line.
This is a convenient way to detect object intersection below the
cursor.
void SoRayPickAction::setNormalizedPoint (const SbVec2f & normpoint) Sets
the viewport-space point which the ray is sent through. The coordinate
is normalized, ranging from (0, 0) to (1, 1).
See also:
setPoint()
void SoRayPickAction::setRadius (const float radiusinpixels) Sets the
radius of the picking ray, in screen pixels. Default value is 5.0.
The radius of the intersection ray will only influence the pick
operation’s behavior versus lines and points, and has no effect on
picking of shapes / polygons.
void SoRayPickAction::setRay (const SbVec3f & start, const SbVec3f &
direction, float neardistance = -1.0, float fardistance = -1.0) Sets
the intersection ray in world-space coordinates.
Use this method if you want to send any ray through the scene to detect
intersections, independently of mouse cursor position upon clicks and
scene graph camera settings.
void SoRayPickAction::setPickAll (const SbBool flag) Lets you decide
whether or not all the objects the ray intersects with should be
picked. If not, only the intersection point of the object closest to
the camera will be picked.
Default value of the ’pick all’ flag is FALSE.
SbBool SoRayPickAction::isPickAll (void) const Returns whether only the
closest object or all the objects the ray intersects with is picked.
See also:
setPickAll()
const SoPickedPointList & SoRayPickAction::getPickedPointList (void) const
Returns a list of the picked points.
SoPickedPoint * SoRayPickAction::getPickedPoint (const int index = 0) const
Returns the picked point with index in the list of picked points.
Returns NULL if less than index + 1 points where picked during the last
raypick action.
void SoRayPickAction::computeWorldSpaceRay (void) This API member is
considered internal to the library, as it is not likely to be of
interest to the application programmer.
SbBool SoRayPickAction::hasWorldSpaceRay (void) const This API member is
considered internal to the library, as it is not likely to be of
interest to the application programmer.
void SoRayPickAction::setObjectSpace (void) This API member is considered
internal to the library, as it is not likely to be of interest to the
application programmer.
void SoRayPickAction::setObjectSpace (const SbMatrix & matrix) This API
member is considered internal to the library, as it is not likely to be
of interest to the application programmer.
SbBool SoRayPickAction::intersect (const SbVec3f & v0_in, const SbVec3f &
v1_in, const SbVec3f & v2_in, SbVec3f & intersection, SbVec3f &
barycentric, SbBool & front) const This API member is considered
internal to the library, as it is not likely to be of interest to the
application programmer.
SbBool SoRayPickAction::intersect (const SbVec3f & v0_in, const SbVec3f &
v1_in, SbVec3f & intersection) const This API member is considered
internal to the library, as it is not likely to be of interest to the
application programmer.
SbBool SoRayPickAction::intersect (const SbVec3f & point_in) const This API
member is considered internal to the library, as it is not likely to be
of interest to the application programmer.
SbBool SoRayPickAction::intersect (const SbBox3f & box, const SbBool
usefullviewvolume = 1) This API member is considered internal to the
library, as it is not likely to be of interest to the application
programmer.
SbBool SoRayPickAction::intersect (const SbBox3f & box, SbVec3f &
intersection, const SbBool usefullviewvolume = 1) This API member is
considered internal to the library, as it is not likely to be of
interest to the application programmer.
const SbViewVolume & SoRayPickAction::getViewVolume (void) This API member
is considered internal to the library, as it is not likely to be of
interest to the application programmer.
const SbLine & SoRayPickAction::getLine (void) This API member is
considered internal to the library, as it is not likely to be of
interest to the application programmer.
SbBool SoRayPickAction::isBetweenPlanes (const SbVec3f & intersection_in)
const This API member is considered internal to the library, as it is
not likely to be of interest to the application programmer.
SoPickedPoint * SoRayPickAction::addIntersection (const SbVec3f &
objectspacepoint_in, SbBool frontpick = 1) This API member is
considered internal to the library, as it is not likely to be of
interest to the application programmer.
void SoRayPickAction::reset (void) Truncates the internal picked points
list.
Since:
Coin 2.2
void SoRayPickAction::beginTraversal (SoNode * node) [protected, virtual]
This virtual method is called from SoAction::apply(), and is the entry
point for the actual scenegraph traversal.
It can be overridden to initialize the action at traversal start, for
specific initializations in the action subclasses inheriting SoAction.
Default method just calls traverse(), which any overridden
implementation of the method must do too (or call
SoAction::beginTraversal()) to trigger the scenegraph traversal.
Reimplemented from SoPickAction.
Author
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