NAME
SoSwitch -
The SoSwitch class is a group node which selects one child subgraph for
traversal.
Which child to traverse is controlled by the application programmer by
using the SoSwitch::whichChild field. In addition to picking out a
single child for traversal, it is also possible to flip all children on
or off for traversal.
SYNOPSIS
#include <Inventor/nodes/SoSwitch.h>
Inherits SoGroup.
Inherited by SoBlinker.
Public Member Functions
SoSwitch (void)
SoSwitch (int numchildren)
virtual SbBool affectsState (void) const
virtual void doAction (SoAction *action)
virtual void callback (SoCallbackAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void pick (SoPickAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void handleEvent (SoHandleEventAction *action)
virtual void getMatrix (SoGetMatrixAction *action)
virtual void search (SoSearchAction *action)
virtual void write (SoWriteAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual void audioRender (SoAudioRenderAction *action)
virtual void notify (SoNotList *nl)
Static Public Member Functions
static void initClass (void)
Public Attributes
SoSFInt32 whichChild
Protected Member Functions
virtual ~SoSwitch ()
void traverseChildren (SoAction *action)
Detailed Description
The SoSwitch class is a group node which selects one child subgraph for
traversal.
Which child to traverse is controlled by the application programmer by
using the SoSwitch::whichChild field. In addition to picking out a
single child for traversal, it is also possible to flip all children on
or off for traversal.
This node is very useful for conditionally turning on or off parts of
the scenegraph based on the current application processing mode,
visualizing mode, or whatever else the application can do.
FILE FORMAT/DEFAULTS:
Switch {
whichChild -1
}
Constructor & Destructor Documentation
SoSwitch::SoSwitch (void) Default constructor.
SoSwitch::SoSwitch (int numchildren) Constructor.
The argument should be the approximate number of children which is
expected to be inserted below this node. The number need not be exact,
as it is only used as a hint for better memory resource allocation.
SoSwitch::~SoSwitch () [protected, virtual] Destructor.
Member Function Documentation
void SoSwitch::initClass (void) [static] Sets up initialization for data
common to all instances of this class, like submitting necessary
information to the Coin type system.
Reimplemented from SoGroup.
Reimplemented in SoBlinker.
SbBool SoSwitch::affectsState (void) const [virtual] Returns TRUE if the
node could have any effect on the state during traversal.
If it returns FALSE, no data in the traversal-state will change from
the pre-traversal state to the post-traversal state. The SoSeparator
node will for instance return FALSE, as it pushes and pops the state
before and after traversal of its children. All SoShape nodes will also
return FALSE, as just pushing out geometry data to the rendering engine
won’t affect the actual rendering state.
The default method returns TRUE, on a ’better safe than sorry’
philosophy.
Reimplemented from SoNode.
void SoSwitch::doAction (SoAction * action) [virtual] This function
performs the typical operation of a node for any action.
Reimplemented from SoGroup.
void SoSwitch::callback (SoCallbackAction * action) [virtual] Action method
for SoCallbackAction.
Simply updates the state according to how the node behaves for the
render action, so the application programmer can use the
SoCallbackAction for extracting information about the scene graph.
Reimplemented from SoGroup.
void SoSwitch::GLRender (SoGLRenderAction * action) [virtual] Action method
for the SoGLRenderAction.
This is called during rendering traversals. Nodes influencing the
rendering state in any way or who wants to throw geometry primitives at
OpenGL overrides this method.
Reimplemented from SoGroup.
void SoSwitch::pick (SoPickAction * action) [virtual] Action method for
SoPickAction.
Does common processing for SoPickAction action instances.
Reimplemented from SoGroup.
void SoSwitch::getBoundingBox (SoGetBoundingBoxAction * action) [virtual]
Action method for the SoGetBoundingBoxAction.
Calculates bounding box and center coordinates for node and modifies
the values of the action to encompass the bounding box for this node
and to shift the center point for the scene more towards the one for
this node.
Nodes influencing how geometry nodes calculates their bounding box also
overrides this method to change the relevant state variables.
Reimplemented from SoGroup.
Reimplemented in SoBlinker.
void SoSwitch::handleEvent (SoHandleEventAction * action) [virtual] Action
method for SoHandleEventAction.
Inspects the event data from action, and processes it if it is
something which this node should react to.
Nodes influencing relevant state variables for how event handling is
done also overrides this method.
Reimplemented from SoGroup.
void SoSwitch::getMatrix (SoGetMatrixAction * action) [virtual] Action
method for SoGetMatrixAction.
Updates action by accumulating with the transformation matrix of this
node (if any).
Reimplemented from SoGroup.
void SoSwitch::search (SoSearchAction * action) [virtual] Action method for
SoSearchAction.
Compares the search criteria from the action to see if this node is a
match. Searching is done by matching up all criteria set up in the
SoSearchAction -- if any of the requested criteria is a miss, the
search is not deemed successful for the node.
See also:
SoSearchAction
Reimplemented from SoGroup.
void SoSwitch::write (SoWriteAction * action) [virtual] Action method for
SoWriteAction.
Writes out a node object, and any connected nodes, engines etc, if
necessary.
Reimplemented from SoGroup.
Reimplemented in SoBlinker.
void SoSwitch::getPrimitiveCount (SoGetPrimitiveCountAction * action)
[virtual] Action method for the SoGetPrimitiveCountAction.
Calculates the number of triangle, line segment and point primitives
for the node and adds these to the counters of the action.
Nodes influencing how geometry nodes calculates their primitive count
also overrides this method to change the relevant state variables.
Reimplemented from SoGroup.
void SoSwitch::audioRender (SoAudioRenderAction * action) [virtual] Action
method for SoAudioRenderAction.
Does common processing for SoAudioRenderAction action instances.
Reimplemented from SoGroup.
void SoSwitch::notify (SoNotList * l) [virtual] Notifies all auditors for
this instance when changes are made.
Reimplemented from SoNode.
Reimplemented in SoBlinker.
void SoSwitch::traverseChildren (SoAction * action) [protected] This
function was part of the original SGI Inventor API, but it is not
supported in Coin, as it looks like it should probably have been
private in Inventor.
Member Data Documentation
SoSFInt32 SoSwitch::whichChild Selects which child to traverse during
rendering (and some other) actions.
The value should be either SO_SWITCH_NONE (for traversing no children,
like it was an empty SoGroup node), SO_SWITCH_ALL (for traversing like
if we were an SoGroup node), SO_SWITCH_INHERIT (for traversing the same
child as the last SoSwitch node), or an index value for a child.
When using SO_SWITCH_INHERIT, it is important to understand how the
SoSwitch-node is affected by other SoSwitch-nodes. If you have several
switches in the scenegraph, the last switch with its whichChild field
set to anything but SO_SWITCH_INHERIT will be used. The switch does not
only inherit from its parent switch node, but also from its siblings,
located anywhere before it in the scenegraph. An example will help
clarify this:
#Inventor V2.1 ascii
Separator {
Switch {
whichChild 0
Group {
Switch {
whichChild 1
BaseColor { rgb 1 0 0 } # red
BaseColor { rgb 1 1 0 } # yellow
}
Switch {
whichChild -2 # SO_SWITCH_INHERIT
BaseColor { rgb 0 1 0 } # green
BaseColor { rgb 0 0 1 } # blue
}
Cube { }
}
}
}
This results in a blue cube on the screen. The reason being that the
value of the previous whichChild field was inherited by the final
switch, making it select child 1 - the blue BaseColor.
When constructing ascii Inventor files, the integer values for the
keywords must be used instead of their names. They are -1 for
SO_SWITCH_NONE, -2 for SO_SWITCH_INHERIT, and -3 for SO_SWITCH_ALL.
Default value for the field is SO_SWITCH_NONE.
Author
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