NAME
SoSeparator -
The SoSeparator class is a state-preserving group node.
Subgraphs parented by SoSeparator nodes will not affect the state, as
they push and pop the traversal state before and after traversal of its
children.
SYNOPSIS
#include <Inventor/nodes/SoSeparator.h>
Inherits SoGroup.
Inherited by SoAnnotation, SoGeoSeparator, SoLocateHighlight,
SoSelection, and SoShadowGroup.
Public Types
enum CacheEnabled { OFF, ON, AUTO }
Public Member Functions
SoSeparator (void)
SoSeparator (const int nchildren)
virtual void doAction (SoAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void GLRenderBelowPath (SoGLRenderAction *action)
virtual void GLRenderInPath (SoGLRenderAction *action)
virtual void GLRenderOffPath (SoGLRenderAction *action)
virtual void callback (SoCallbackAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void getMatrix (SoGetMatrixAction *action)
virtual void handleEvent (SoHandleEventAction *action)
virtual void rayPick (SoRayPickAction *action)
virtual void search (SoSearchAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual void audioRender (SoAudioRenderAction *action)
virtual void notify (SoNotList *nl)
virtual SbBool affectsState (void) const
Static Public Member Functions
static void initClass (void)
static void setNumRenderCaches (const int howmany)
static int getNumRenderCaches (void)
Public Attributes
SoSFEnum renderCaching
SoSFEnum boundingBoxCaching
SoSFEnum renderCulling
SoSFEnum pickCulling
Protected Member Functions
virtual ~SoSeparator ()
virtual SbBool cullTest (SoState *state)
virtual SbBool cullTest (SoGLRenderAction *action, int &cullresults)
virtual SbBool readInstance (SoInput *in, unsigned short flags)
Detailed Description
The SoSeparator class is a state-preserving group node.
Subgraphs parented by SoSeparator nodes will not affect the state, as
they push and pop the traversal state before and after traversal of its
children.
SoSeparator nodes also provides options for traversal optimalization
through the use of caching.
FILE FORMAT/DEFAULTS:
Separator {
renderCaching AUTO
boundingBoxCaching AUTO
renderCulling AUTO
pickCulling AUTO
}
See also:
SoTransformSeparator
Member Enumeration Documentation
enum SoSeparator::CacheEnabled Enumeration of flags for the fields deciding
which optimalizations to do in SoSeparator nodes. There are two types
of settings available: caching policies or culling policies. See
doumentation of fields.
Enumerator:
OFF No caching.
ON Always try to cache state.
AUTO Use heuristics to try to figure out the optimal caching policy.
Constructor & Destructor Documentation
SoSeparator::SoSeparator (void) Default constructor.
SoSeparator::SoSeparator (const int nchildren) 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.
SoSeparator::~SoSeparator () [protected, virtual] Destructor. Frees
resources used to implement caches.
Member Function Documentation
void SoSeparator::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 SoShadowGroup, SoAnnotation, SoExtSelection,
SoGeoSeparator, SoLocateHighlight, SoSelection, and SoWWWAnchor.
void SoSeparator::doAction (SoAction * action) [virtual] This function
performs the typical operation of a node for any action.
Reimplemented from SoGroup.
void SoSeparator::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.
Reimplemented in SoAnnotation.
void SoSeparator::GLRenderBelowPath (SoGLRenderAction * action) [virtual]
SGI Open Inventor v2.1 obsoleted support for
SoGLRenderAction::addMethod(). Instead, GLRender() might be called
directly, and to optimize traversal, the SoSeparator node calls
GLRenderBelowPath whenever the path code is BELOW_PATH or NO_PATH (path
code is guaranteed not to change). To be compatible with SGI’s Inventor
(and thereby also TGS’) we have chosen to follow their implementation
in this respect.
SoSeparator::GLRenderBelowPath() do not traverse its children using
SoChildList::traverse(), but calls GLRenderBelowPath() directly for all
its children.
Reimplemented from SoNode.
Reimplemented in SoShadowGroup, SoAnnotation, SoExtSelection,
SoGeoSeparator, and SoLocateHighlight.
void SoSeparator::GLRenderInPath (SoGLRenderAction * action) [virtual]
Implements the SoAction::IN_PATH traversal method for the rendering
action.
Reimplemented from SoNode.
Reimplemented in SoShadowGroup, SoAnnotation, SoGeoSeparator, and
SoLocateHighlight.
void SoSeparator::GLRenderOffPath (SoGLRenderAction * action) [virtual]
Implements the SoAction::OFF_PATH traversal method for the rendering
action.
Reimplemented from SoNode.
Reimplemented in SoAnnotation.
void SoSeparator::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.
Reimplemented in SoGeoSeparator.
void SoSeparator::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 SoGeoSeparator.
void SoSeparator::getMatrix (SoGetMatrixAction * action) [virtual] Action
method for SoGetMatrixAction.
Updates action by accumulating with the transformation matrix of this
node (if any).
Reimplemented from SoGroup.
Reimplemented in SoGeoSeparator.
void SoSeparator::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.
Reimplemented in SoExtSelection, SoLocateHighlight, SoSelection, and
SoWWWAnchor.
void SoSeparator::rayPick (SoRayPickAction * action) [virtual] Action
method for SoRayPickAction.
Checks the ray specification of the action and tests for intersection
with the data of the node.
Nodes influencing relevant state variables for how picking is done also
overrides this method.
Reimplemented from SoNode.
Reimplemented in SoGeoSeparator.
void SoSeparator::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 SoSeparator::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.
Reimplemented in SoGeoSeparator.
void SoSeparator::audioRender (SoAudioRenderAction * action) [virtual]
Action method for SoAudioRenderAction.
Does common processing for SoAudioRenderAction action instances.
Reimplemented from SoGroup.
void SoSeparator::notify (SoNotList * l) [virtual] Notifies all auditors
for this instance when changes are made.
Reimplemented from SoNode.
Reimplemented in SoShadowGroup.
void SoSeparator::setNumRenderCaches (const int howmany) [static] Set the
maximum number of caches that SoSeparator nodes may allocate for render
caching.
This is a global value which will be used for all SoSeparator nodes,
but the value indicate the maximum number per SoSeparator node.
More caches might give better performance, but will use more memory.
The built-in default value is 2.
The value can also be changed globally by setting the host system’s
environment variable IV_SEPARATOR_MAX_CACHES to the wanted number. This
is primarily meant as an aid during debugging, to make it easy to turn
off rendercaching completely (by setting ’IV_SEPARATOR_MAX_CACHES=0’)
without having to change any application code.
int SoSeparator::getNumRenderCaches (void) [static] Returns maximum number
of caches SoSeparator nodes are allowed to use for render caching.
See also:
setNumRenderCaches()
SbBool SoSeparator::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.
SbBool SoSeparator::cullTest (SoState * state) [protected, virtual]
Internal method which do view frustum culling. For now, view frustum
culling is performed if the renderCulling field is AUTO or ON, and the
bounding box cache is valid.
Returns TRUE if this separator is outside view frustum, FALSE if
inside.
SbBool SoSeparator::cullTest (SoGLRenderAction * action, int & cullresults)
[protected, virtual] This is an internal Open Inventor method. We’ve
implemented view frustum culling in a different manner. Let us know if
you need this function, and we’ll consider implementing it.
SbBool SoSeparator::readInstance (SoInput * in, unsigned short flags)
[protected, virtual] This method is mainly intended for internal use
during file import operations.
It reads a definition of an instance from the input stream in. The
input stream state points to the start of a serialized / persistant
representation of an instance of this class type.
TRUE or FALSE is returned, depending on if the instantiation and
configuration of the new object of this class type went ok or not. The
import process should be robust and handle corrupted input streams by
returning FALSE.
flags is used internally during binary import when reading user
extension nodes, group nodes or engines.
Reimplemented from SoGroup.
Member Data Documentation
SoSFEnum SoSeparator::renderCaching Policy for caching of rendering
instructions for faster execution. This will typically use the OpenGL
displaylist mechanism.
Default value is SoSeparator::AUTO.
If you know that some parts of your scene will never change, rendering
might happen faster if you explicitly set this field to
SoSeparator::ON. If you on the other hand know that parts of the scene
will change a lot (like for every redraw), it will be beneficial to set
this field to SoSeparator::OFF for the top-level separator node of this
(sub)graph.
Usually the default setting of AUTO will handle any scene very well.
The advantages that can be had from setting SoSeparator::renderCaching
to ON are:
· If you positively know that the geometry under the SoSeparator is
static, you get the cache set up right away.
Otherwise, the code in Coin will do a bit of testing and decide by some
heuristics whether or not to enable it. That will make the rendering be
a tiny bit slower right after start-up than with renderCaching set to
ON.
(The slow-down should hardly be noticable, though, so we don’t advice
application programmers to do this.)
· For many of the shape nodes that can contain many basic primitives,
like e.g. SoFaceSet, SoIndexedFaceSet, SoLineSet, etc etc, there is
an internal threshold for how many primitives a node can contain
before we don’t do caching when SoSeparator::renderCaching is set to
AUTO.
The reason we do this is because OpenGL renderlists can potentially
suck up a lot of memory resources on the graphics card.
But if you know that it will be advantageous on your particular
platform, you can override this by setting SoSeparator::renderCaching
equal to ON.
(We don’t advice application programmers to do this either. A better
solution in these cases would simply be to get in touch with SIM and
describe the platform and the problem, and we could integrate a proper
fix into Coin.)
There are good reasons for setting renderCaching to OFF, like when you
know the geometry will be changing a lot. Still, Coin should work
fairly well without even this optimization. (If renderCaching is AUTO
over a sub-graph with changing geometry or other cache smashing nodes,
the caching heuristics will stop the SoSeparator node from trying to
make caches -- at least after a few tries has been made and failed.)
The short story about how auto-caching works is as follows:
· For vertex-based shapes with fewer than 100 triangles and where the
geometry is detected to be fairly static, caching is enabled.
· For shapes with more than 1000 trangles, it is disabled, to avoid
spending too much of the on-board graphics card’s memory resources.
· For shapes with between 100 and 1000 shapes, displaylist caching will
be turned on if our heuristics decides that the geometry can be
considered static.
The maximum threshold (of 1000) is higher when doing remote rendering
(as when rendering from one X11-based system to another).
Disabling the displaylist caching takes precedence over enabling, so if
you have an SoSeparator with a shape with more than 1000 triangles and
a shape with fewer than 100 triangles, caching will be disabled for the
SoSeparator.
It’s possible to tune the limits using some environment variables:
· COIN_AUTOCACHE_LOCAL_MIN can be used to change the enable-caching
limit, while COIN_AUTOCACHE_LOCAL_MAX controls the disable-caching
limit.
· The corresponding variables for remote rendering are
COIN_AUTOCACHE_REMOTE_MIN and COIN_AUTOCACHE_REMOTE_MAX.
SoSFEnum SoSeparator::boundingBoxCaching Policy for caching bounding box
calculations. Default value is SoSeparator::AUTO.
See also documentation for SoSeparator::renderCaching.
SoSFEnum SoSeparator::renderCulling Policy for doing viewport culling
during rendering traversals. Default value is SoSeparator::AUTO.
When the render culling is turned off for Coin, it will be left to be
done for the underlying immediate mode rendering library. This will
often be faster than doing culling from within Coin, so be careful to
monitor the change in execution speed if setting this field to
SoSeparator::ON.
See also documentation for SoSeparator::renderCaching.
SoSFEnum SoSeparator::pickCulling Policy for doing viewport culling during
pick traversals. Default value is SoSeparator::AUTO.
See documentation for SoSeparator::renderCulling.
Author
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