SOINTERSECTIONDETECTIONACTION(3coin3)

📦 version 3.1.3, in fedora 43, fedora 44

💖 SoIntersectionDetectionAction(3) 💖

okay bestie, so this one lives in the Library Functions Manual, section 3, and it's a coin3 thing. grab a snack, it's a long one (part 1 of 2, more coming, don't go anywhere) ✨

🌸 NAME 🌸

SoIntersectionDetectionAction — the SoIntersectionDetectionAction class is for detecting intersecting primitives in a scene. yes, it finds the shapes that are bumping into each other. lowkey iconic 🦋

✨ SYNOPSIS ✨

#include <Inventor/collision/SoIntersectionDetectionAction.h>

Inherits SoAction.

💅 Public Types 💅

  • enum Resp { NEXT_PRIMITIVE, NEXT_SHAPE, ABORT }
  • typedef SoCallbackAction::Response SoIntersectionVisitationCB(void *closure, const SoPath *where)
  • typedef SbBool SoIntersectionFilterCB(void *closure, const SoPath *p1, const SoPath *p2)
  • typedef Resp SoIntersectionCB(void *closure, const SoIntersectingPrimitive *p1, const SoIntersectingPrimitive *p2)

🎀 Public Types inherited from SoAction 🎀

  • enum AppliedCode { NODE = 0, PATH = 1, PATH_LIST = 2 }
  • enum PathCode { NO_PATH = 0, IN_PATH = 1, BELOW_PATH = 2, OFF_PATH = 3 }

🌈 Public Member Functions 🌈

  • virtual SoType getTypeId (void) const
  • void setIntersectionDetectionEpsilon (float epsilon)
  • float getIntersectionDetectionEpsilon (void) const
  • void setTypeEnabled (SoType type, SbBool enable)
  • SbBool isTypeEnabled (SoType type, SbBool checkgroups=FALSE) const
  • void setManipsEnabled (SbBool enable)
  • SbBool isManipsEnabled (void) const
  • void setDraggersEnabled (SbBool enable)
  • SbBool isDraggersEnabled (void) const
  • void setShapeInternalsEnabled (SbBool enable)
  • SbBool isShapeInternalsEnabled (void) const
  • void addVisitationCallback (SoType type, SoIntersectionVisitationCB *cb, void *closure)
  • void removeVisitationCallback (SoType type, SoIntersectionVisitationCB *cb, void *closure)
  • virtual void apply (SoNode *node)
  • virtual void apply (SoPath *path)
  • virtual void apply (const SoPathList &paths, SbBool obeysRules=FALSE)
  • virtual void setFilterCallback (SoIntersectionFilterCB *cb, void *closure=NULL)
  • virtual void addIntersectionCallback (SoIntersectionCB *cb, void *closure=NULL)
  • virtual void removeIntersectionCallback (SoIntersectionCB *cb, void *closure=NULL)

🧚 Public Member Functions inherited from SoAction 🧚

  • virtual ~SoAction (void)
  • virtual SbBool isOfType (SoType type) const
  • void apply (SoAction *beingApplied)
  • virtual void invalidateState (void)
  • AppliedCode getWhatAppliedTo (void) const
  • SoNode * getNodeAppliedTo (void) const
  • SoPath * getPathAppliedTo (void) const
  • const SoPathList * getPathListAppliedTo (void) const
  • const SoPathList * getOriginalPathListAppliedTo (void) const
  • SbBool isLastPathListAppliedTo (void) const
  • PathCode getPathCode (int &numindices, const int *&indices)
  • void traverse (SoNode *const node)
  • SbBool hasTerminated (void) const
  • const SoPath * getCurPath (void)
  • SoState * getState (void) const
  • PathCode getCurPathCode (void) const
  • virtual SoNode * getCurPathTail (void)
  • void usePathCode (int &numindices, const int *&indices)
  • void pushCurPath (const int childindex, SoNode *node=NULL)
  • void popCurPath (const PathCode prevpathcode)
  • void pushCurPath (void)
  • void popPushCurPath (const int childindex, SoNode *node=NULL)
  • void popCurPath (void)
  • void switchToPathTraversal (SoPath *path)
  • void switchToNodeTraversal (SoNode *node)

⭐ Static Public Member Functions ⭐

  • static SoType getClassTypeId (void)
  • static void addMethod (const SoType type, SoActionMethod method)
  • static void enableElement (const SoType type, const int stackindex)
  • static void initClass (void)
  • static void setIntersectionEpsilon (float epsilon)
  • static float getIntersectionEpsilon (void)

🌟 Static Public Member Functions inherited from SoAction 🌟

  • static void initClass (void)
  • static void initClasses (void)
  • static SoType getClassTypeId (void)
  • static void nullAction (SoAction *action, SoNode *node)

🎀 Protected Member Functions 🎀

  • virtual const SoEnabledElementsList & getEnabledElements (void) const

💜 Protected Member Functions inherited from SoAction 💜

  • SoAction (void)
  • virtual void beginTraversal (SoNode *node)
  • virtual void endTraversal (SoNode *node)
  • void setTerminated (const SbBool flag)
  • virtual SbBool shouldCompactPathList (void) const

🦋 Static Protected Member Functions 🦋

  • static SoEnabledElementsList * getClassEnabledElements (void)
  • static SoActionMethodList * getClassActionMethods (void)

🍓 Static Protected Member Functions inherited from SoAction 🍓

  • static SoEnabledElementsList * getClassEnabledElements (void)
  • static SoActionMethodList * getClassActionMethods (void)

🌈 Additional Inherited Members 🌈

🧁 Protected Attributes inherited from SoAction 🧁

  • SoState * state
  • SoActionMethodList * traversalMethods

👑 Detailed Description 👑

The SoIntersectionDetectionAction class is for detecting intersecting primitives in a scene. fr fr, that's the whole job.

Note that only collisions between actual geometry in the scene is detected, so the contents of some special nodes like e.g. SoText2 and SoImage (which projects to screen-plane bitmap graphics, and not actual polygons) will not be considered for collision detection. so don't come for this class when your text didn't register as a hit, bestie, it literally wasn't invited to the party 🙈

Note also that the SoIntersectionDetectionAction class is not a high-performance component in Coin. Using it in a continuous manner over complex scene graphs is doomed to be a performance killer. 💀 like, it will eat your frame rate for breakfast. please be mindful.

Below is a simple usage example for this class. It was written as a stand-alone framework set up for profiling and optimization of the SoIntersectionDetectionAction. It tests intersection of all shapes against each other for the loaded file.

#include <cstdlib>
#include <Inventor/SbTime.h>
#include <Inventor/SoDB.h>
#include <Inventor/SoInteraction.h>
#include <Inventor/collision/SoIntersectionDetectionAction.h>
#include <Inventor/errors/SoDebugError.h>
#include <Inventor/nodekits/SoNodeKit.h>
#include <Inventor/nodes/SoSeparator.h>

static SoIntersectionDetectionAction::Resp
intersectionCB(void * closure,
               const SoIntersectingPrimitive * pr1,
               const SoIntersectingPrimitive * pr2)
{
  (void)fprintf(stdout, "intersection hit!\n");
  return SoIntersectionDetectionAction::NEXT_PRIMITIVE;
}

int
main(int argc, char ** argv)
{
  SoDB::init();
  SoNodeKit::init();
  SoInteraction::init();

  if (argc != 2) {
    (void)fprintf(stderr, "\n\\tUsage: testapp <filename.iv>\n\n");
    exit(1);
  }

  SoInput in;
  SbBool ok = in.openFile(argv[1]);
  assert(ok);
  SoSeparator * root = SoDB::readAll(&in);
  assert(root);

  root->ref();

  SoIntersectionDetectionAction ida;
  ida.addIntersectionCallback(intersectionCB, NULL);
  ida.setManipsEnabled(FALSE);
  ida.setDraggersEnabled(FALSE);
  ida.setIntersectionDetectionEpsilon(10.0f);

  SbTime starttime = SbTime::getTimeOfDay();
  SoDebugError::postInfo("main", "SoIntersectionDetectionAction::apply");

  ida.apply(root);

  SoDebugError::postInfo("main", "apply() done after %f seconds.",
                         (SbTime::getTimeOfDay() - starttime).getValue());

  root->unref();

  return 0;
}

🌸 Since 🌸

  • Coin 2.1
  • TGS Inventor 2.4

okay that's part 1 bestie, stay tuned, part 2 is coming and it's gonna slay 💅✨

👑 MEMBER FUNCTION DOCUMENTATION 👑

okay bestie, this is the part where we go function by function. grab a snack. 🍓

SoType SoIntersectionDetectionAction::getTypeId (void ) const — virtual ✨

Returns the type identification of an action derived from a class inheriting SoAction. It's used for run-time type checking and "downward" casting, and no, "downward casting" is not a personal attack, it's just how Coin figures out what it's actually holding.

Usage example, straight from the source:

void bar(SoAction * action)
{
  if (action->getTypeId() == SoGLRenderAction::getClassTypeId()) {
    // safe downward cast, know the type
    SoGLRenderAction * glrender = (SoGLRenderAction *)action;
  }
  return; // ignore if not renderaction
}

So for all you application programmers who wanna extend the library with brand new actions: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through Inventor/nodes/SoSubAction.h: SO_ACTION_SOURCE, SO_ACTION_INIT_CLASS and SO_ACTION_CONSTRUCTOR.

Wanna know more about writing Coin extensions? Go read the SoAction class documentation, it's right there. 💜

Returns the actual type id of an object derived from a class inheriting SoAction. Needs to be overridden in all subclasses.

Implements SoAction.

void SoIntersectionDetectionAction::addMethod (const SoType type, SoActionMethod method) — static 🔒

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. Like, mind ya business, it's a library thing. 🙈

void SoIntersectionDetectionAction::enableElement (const SoType type, const int stackindex) — static 🔒

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. Same energy, different function. 💀

const SoEnabledElementsList & SoIntersectionDetectionAction::getEnabledElements (void ) const — protected, virtual

Returns a list of the elements used by action instances of this class upon traversal operations. It's giving backstage pass to the element list. 🎀

Reimplemented from SoAction.

void SoIntersectionDetectionAction::setIntersectionDetectionEpsilon (float epsilon)

Sets the intersection detection distance epsilon value for the action object. This overrides the global value, so it's the local main character of epsilon settings. 👑

See also SoIntersectionDetectionAction::setIntersectionEpsilon() for important information about how this setting influences performance. fr, go read that one, it matters.

float SoIntersectionDetectionAction::getIntersectionDetectionEpsilon (void ) const

Returns the set intersection detection distance epsilon value for the action object. That's it, that's the whole vibe. ✨

void SoIntersectionDetectionAction::setIntersectionEpsilon (float epsilon) — static

Sets the global intersection detection distance epsilon value. 🌍

This makes primitives within the epsilon distance be considered to intersect each other.

This will affect all intersection detection action objects in use that don't have a locally set value.

The epsilon value is a worldspace value.

⚠️ Be aware that increasing the epsilon value can dramatically increase the number of primitive intersection tests being done to decide intersections. Increasing the epsilon value can therefore cause serious slow-downs in the running time of the intersections checks. Like bestie, crank it and watch your framerate simply leave the chat. 😭

float SoIntersectionDetectionAction::getIntersectionEpsilon (void ) — static

Returns the globally set intersection detection distance epsilon value. No thoughts, just the number. 🦋

void SoIntersectionDetectionAction::setTypeEnabled (SoType type, SbBool enable)

Sets whether nodes of specific types (including derived objects) should be tested for intersection or not. You're basically curating the guest list for intersection testing. 💅

See also isTypeEnabled(), setManipsEnabled(), setDraggersEnabled()

SbBool SoIntersectionDetectionAction::isTypeEnabled (SoType type, SbBool checkgroups = FALSE) const

Returns whether nodes of specific types are enabled or not. The checkgroups argument can be set to TRUE if you want the return value to reflect whether the node will be implicitly enabled/disabled through the settings controlled by the setManipsEnabled() and setDraggersEnabled() functions.

The default is that all node types are enabled.

📌 Note that derivation checks are not performed — the type needs to be the exact same type as has been disabled with setTypeEnabled(). No inheritance nepotism here, bestie.

See also setTypeEnabled()

void SoIntersectionDetectionAction::setManipsEnabled (SbBool enable)

Sets whether manipulators in the scene graph should be tested for intersection with other geometry or not.

📌 Note that when draggers are disabled with setDraggersEnabled(), this setting has no effect — manipulators are disabled too. They're a package deal, iykyk.

See also isManipsEnabled(), setDraggersEnabled(), setTypeEnabled()

SbBool SoIntersectionDetectionAction::isManipsEnabled (void ) const

Returns whether the action is set up to test intersection on manipulators in the scene or not.

📌 Note that when draggers are disabled with setDraggersEnabled(), this setting has no effect — manipulators are disabled too.

The default is that manipulators are enabled for intersection testing with other geometry in the scene.

See also setManipsEnabled()

void SoIntersectionDetectionAction::setDraggersEnabled (SbBool enable)

Sets whether draggers in the scene graph should be tested for intersection with other geometry or not.

📌 Note that when you disable draggers, manipulators are also automatically disabled, although the isManipsDisabled() setting might reflect otherwise. Sneaky, but that's the tea. ☕

See also isDraggersEnabled(), setManipsEnabled(), setTypeEnabled()

SbBool SoIntersectionDetectionAction::isDraggersEnabled (void ) const

Returns whether the action is set up to test intersection on draggers in the scene or not.

The default is that draggers are enabled for intersection testing with other geometry in the scene.

See also setDraggersEnabled()

void SoIntersectionDetectionAction::setShapeInternalsEnabled (SbBool enable)

Sets whether nodes in the scene graph should be checked for intersecting primitives within themselves. Yes, self-reflection, but geometric. 🪞

Default is FALSE.

See also isShapeInternalsEnabled()

SbBool SoIntersectionDetectionAction::isShapeInternalsEnabled (void ) const

Returns whether nodes in the scene graph will be checked for intersecting primitives within themselves.

The default value for this setting is FALSE.

See also setShapeInternalsEnabled()

void SoIntersectionDetectionAction::addVisitationCallback (SoType type, SoIntersectionVisitationCB * cb, void * closure)

The scene graph traversal can be controlled with callbacks which you set with this method. Use it just like you would use SoCallbackAction::addPreCallback(). Same flavor, different action. 🌈

See also SoCallbackAction::addPreCallback()

void SoIntersectionDetectionAction::removeVisitationCallback (SoType type, SoIntersectionVisitationCB * cb, void * closure)

The scene graph traversal can be controlled with callbacks which you remove with this method. Use it just like you would use SoCallbackAction::removePreCallback(). Un-invite that callback, respectfully. 💅

See also SoCallbackAction::removePreCallback()

void SoIntersectionDetectionAction::apply (SoNode * root) — virtual

Applies the action to the scene graph rooted at root.

⚠️ Note that you should not apply an action to a node with a zero reference count. The behavior in that case is undefined. Not "probably fine", not "vibes-based", undefined. Don't do it. 💀

Reimplemented from SoAction.

void SoIntersectionDetectionAction::apply (SoPath * path) — virtual

Applies the action to the parts of the graph defined by path.

📌 Note that an SoPath will also contain all nodes that may influence e.g. geometry nodes in the path. So for instance applying an SoGLRenderAction on an SoPath will render that path as expected in the view, where geometry will get its materials, textures, and other appearance settings correctly.

If the path ends in an SoGroup node, the action will also traverse the tail node's children. Going all the way down, no shortcuts. 🧚

Reimplemented from SoAction.

void SoIntersectionDetectionAction::apply (const SoPathList & pathlist, SbBool obeysrules = FALSE) — virtual

Applies the action to the graphs defined by pathlist. If obeysrules is set to TRUE, pathlist must obey the following four conditions (which is the case for path lists returned from search actions for non-group nodes and path lists returned from picking actions):

  1. All paths must start at the same head node.
  2. All paths must be sorted in traversal order.
  3. The paths must be unique.
  4. No path can continue through the end point of another path.

See also SoAction::apply(SoPath * path)

Reimplemented from SoAction.

void SoIntersectionDetectionAction::setFilterCallback (SoIntersectionFilterCB * cb, void * closure = NULL) — virtual

This callback is called when two shapes are found to have intersecting bounding boxes, and are about to be checked for real intersection between their primitives. It's the bouncer at the door of the real intersection test. 🚪

When intersection epsilon values are in use, bounding box intersection testing is done approximately and will trigger the filter callback on boxes that are further from each other than the epsilon length.

If the callback returns TRUE, the intersection test will be performed. If the callback returns FALSE, the intersection testing will be skipped.

The API allows only one filter callback. One. Singular. Don't try it. ✋

void SoIntersectionDetectionAction::addIntersectionCallback (SoIntersectionCB * cb, void * closure = NULL) — virtual

Adds a callback to be called when two intersecting primitives are found in the scene. 🎉

If the callback returns ABORT, the intersection detection is aborted. If the callback returns NEXT_SHAPE, the intersection detection between these two shapes is aborted and the action continues checking other shapes. If the callback returns NEXT_PRIMITIVE, the intersection detection testing continues checking the other primitives in these two shapes.

See also removeIntersectionCallback()

void SoIntersectionDetectionAction::removeIntersectionCallback (SoIntersectionCB * cb, void * closure = NULL) — virtual

Removes a callback set with addIntersectionCallback(). Say bye, it's not your era anymore. 🦋

See also addIntersectionCallback()

🌸 AUTHOR 🌸

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