#include <Inventor/actions/SoAction.h>
Inheritance diagram for SoAction:
Public Types | |
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 | ~SoAction () |
virtual SoType | getTypeId (void) const =0 |
virtual SbBool | isOfType (SoType type) const |
virtual void | apply (SoNode *root) |
virtual void | apply (SoPath *path) |
virtual void | apply (const SoPathList &pathlist, SbBool obeysrules=FALSE) |
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 | |
void | initClass (void) |
void | initClasses (void) |
SoType | getClassTypeId (void) |
void | nullAction (SoAction *action, SoNode *node) |
Protected Member Functions | |
SoAction (void) | |
virtual void | beginTraversal (SoNode *node) |
virtual void | endTraversal (SoNode *node) |
void | setTerminated (const SbBool flag) |
virtual const SoEnabledElementsList & | getEnabledElements (void) const |
virtual SbBool | shouldCompactPathList (void) const |
Static Protected Member Functions | |
SoEnabledElementsList * | getClassEnabledElements (void) |
SoActionMethodList * | getClassActionMethods (void) |
Protected Attributes | |
SoState * | state |
SoActionMethodList * | traversalMethods |
Applying actions is the basic mechanism in Coin for executing various operations on scene graphs or paths within scene graphs, including search operations, rendering, interaction through picking, etc.
The basic operation is to instantiate an action, set it up with miscellaneous parameters if necessary, then call it's apply() method on the root node of the scenegraph (or sub-graph of a scenegraph). The action then traverses the scenegraph from the root node, depth-first and left-to-right, applying it's specific processing at the nodes where it is applicable.
(The SoAction and it's derived classes in Coin is an implementation of the design pattern commonly known as the "Visitor" pattern.)
Here's a simple example that shows how to use the SoWriteAction to dump a scenegraph in the Inventor format to a file:
int write_scenegraph(const char * filename, SoNode * root) { SoOutput output; if (output.openFile(filename)) return 0; // This is where the action is. ;-) SoWriteAction wa(&output); wa.apply(root); return 1; }
After traversal, some action types have stored information about the (sub-)scenegraph that was traversed, which you can then inquire about through methods like SoGetBoundingBoxAction::getBoundingBox(), SoRayPickAction::getPickedPoint(), SoGetPrimitiveCountAction::getTriangleCount(), etc etc.
See the various built-in actions for further information (ie the subclasses of this class), or look at the example code applications of the Coin library to see how actions are generally used.
For extending the Coin library with your own classes, we strongly recommend that you make yourself acquainted with the excellent «The Inventor Toolmaker» book (ISBN 0-201-62493-1), which describes the tasks involved in detail. This book was written by the original SGI Inventor designers and explains many of the underlying design ideas, aswell as having lots of hands-on examples on how to extend the Coin toolkit in ways that are true to the fundamental design ideas. («The Inventor Toolmaker» is also available at SGI's online library, at no cost. See Download The Inventor Toolmaker.) Reading the sourcecode of the built-in classes in Coin should also provide very helpful.
The following example shows the basic outline on how to set up your own extension action class:
// This is sample code on how you can get progress indication on Coin // export operations by extending the library with your own action // class. The new class inherits SoWriteAction. The code is presented // as a stand-alone example. // // The general technique is to inherit SoWriteAction and override it's // "entry point" into each node of the scenegraph. The granularity of // the progress callbacks is on a per-node basis, which should usually // be good enough. #include <Inventor/SoDB.h> #include <Inventor/actions/SoWriteAction.h> #include <Inventor/nodes/SoSeparator.h> class MyWriteAction : public SoWriteAction { SO_ACTION_HEADER(SoWriteAction); public: MyWriteAction(SoOutput * out); virtual ~MyWriteAction(); static void initClass(void); protected: virtual void beginTraversal(SoNode * node); private: static void actionMethod(SoAction *, SoNode *); int nrnodes; int totalnrnodes; }; SO_ACTION_SOURCE(MyWriteAction); MyWriteAction::MyWriteAction(SoOutput * out) : SoWriteAction(out) { SO_ACTION_CONSTRUCTOR(MyWriteAction); } MyWriteAction::~MyWriteAction() { } void MyWriteAction::initClass(void) { SO_ACTION_INIT_CLASS(MyWriteAction, SoWriteAction); SO_ACTION_ADD_METHOD(SoNode, MyWriteAction::actionMethod); } void MyWriteAction::beginTraversal(SoNode * node) { this->nrnodes = 0; this->totalnrnodes = 0; SoWriteAction::beginTraversal(node); } void MyWriteAction::actionMethod(SoAction * a, SoNode * n) { // To abort the export process in mid-writing, we could just avoid // calling in to the SoNode::writeS() method. SoNode::writeS(a, n); MyWriteAction * mwa = (MyWriteAction *)a; SoOutput * out = mwa->getOutput(); if (out->getStage() == SoOutput::COUNT_REFS) { mwa->totalnrnodes++; } else { // (out->getStage() == SoOutput::WRITE) mwa->nrnodes++; SbString s; s.sprintf(" # wrote node %p (%d/%d) \n", n, mwa->nrnodes, mwa->totalnrnodes); out->write(s.getString()); } } int main(int argc, char ** argv) { if (argc < 2) { (void)fprintf(stderr, "\n\nUsage: %s <filename>\n\n", argv[0]); exit(1); } SoDB::init(); MyWriteAction::initClass(); SoInput in; if (!in.openFile(argv[1])) { exit(1); } SoSeparator * root = SoDB::readAll(&in); if (!root) { exit(1); } root->ref(); SoOutput out; MyWriteAction mwa(&out); mwa.apply(root); root->unref(); return 0; }
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Enumerated values for what the action was applied to. |
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Enumerated values for how the action is applied to a scene graph. |
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Destructor, free resources. |
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Default constructor, does all necessary toplevel initialization. |
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Initializes the run-time type system for this class, and sets up the enabled elements and action method list. Reimplemented in SoBoxHighlightRenderAction, SoCallbackAction, SoGLRenderAction, SoGetBoundingBoxAction, SoGetMatrixAction, SoGetPrimitiveCountAction, SoHandleEventAction, SoLineHighlightRenderAction, SoPickAction, SoRayPickAction, SoSearchAction, and SoWriteAction. |
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Initialize all the SoAction subclasses. Automatically called from SoAction::initClass(). |
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Returns the run-time type object associated with instances of this class. |
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Returns the type identification of an action derived from a class inheriting SoAction. This is used for run-time type checking and "downward" casting. Usage example:
For application programmers wanting to extend the library with 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. For more information on writing Coin extensions, see the SoAction class documentation. |
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Returns |
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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. Reimplemented in SoBoxHighlightRenderAction, and SoLineHighlightRenderAction. |
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Applies the action to the parts of the graph defined by path. If the path ends in an SoGroup node, the action will also traverse the tail node's children. Reimplemented in SoBoxHighlightRenderAction, and SoLineHighlightRenderAction. |
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Applies action to the graphs defined by pathlist. If obeysrules is set to All paths must start at the same head node. All paths must be sorted in traversal order. The paths must be unique. No path can continue through the end point of another path. Reimplemented in SoBoxHighlightRenderAction, and SoLineHighlightRenderAction. |
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Invalidates the state, forcing it to be recreated at the next apply() invocation. Reimplemented in SoGLRenderAction. |
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This method is used for filling up the lookup tables with void methods. |
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Returns a code indicating what (node, path, or pathlist) the action instance is being applied to. |
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Returns a pointer to the node the action is being applied to.
If action is not being applied to a node (but a path or a pathlist), the method returns |
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Returns the pointer to the path the action is being applied to. The path is managed by the action instance and should not be destroyed or modified by the caller.
If action is not being applied to a path (but a node or a pathlist), the method returns |
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Returns the pointer to the path list the action is currently being applied to. The path list is managed by the action instance and should not be destroyed or modified by the caller.
If action is not being applied to a path list (but a node or a path), the method returns The returned pathlist pointer need not be equal to the list apply() was called with, as the action may have reorganized the path list for efficiency reasons.
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Returns a pointer to the original path list the action is being applied to.
If the action is not being applied to a path list (but a node or a path), the method returns |
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This method is not supported in Coin. It should probably have been private in OIV. |
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Returns a code that indicates where the current node lies with respect to the path(s) the action is being applied to. The arguments indices and numindices are only set if the method returns |
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Traverses a scene graph rooted at node, invoking the action methods of the nodes in the graph. |
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Returns
Note that the termination flag will be
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Returns a pointer to the path generated during traversal, from the root of the traversed graph to the current node. |
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Returns a pointer to the state of the action instance. The state contains the current set of elements used during traversal. |
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Returns the current traversal path code. |
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This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. Reimplemented in SoCallbackAction. |
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This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. |
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Get ready to traverse the childindex'th child. Use this method if the path code might change as a result of this. This method is very internal. Do not use unless you know what you're doing. |
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Pops the current path, and sets the path code to prevpathcode. This method is very internal. Do not use unless you know what you're doing. |
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Pushes a NULL node onto the current path. Use this before traversing all children when you know that the path code will not change while traversing children. This method is very internal. Do not use unless you know what you're doing. |
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Get ready to traverse the childindex'th child. Use this method if you know the path code will not change as a result of this. This method is very internal. Do not use unless you know what you're doing. |
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Pops of the last child in the current path. Use this if you know the path code hasn't changed since the current path was pushed. This method is very internal. Do not use unless you know what you're doing. |
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Store our state, traverse the given path, restore our state and continue traversal. |
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Store our state, traverse the subgraph rooted at the given node, restore our state and continue traversal. |
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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 in SoCallbackAction, SoGLRenderAction, SoGetBoundingBoxAction, SoGetMatrixAction, SoGetPrimitiveCountAction, SoHandleEventAction, SoPickAction, SoRayPickAction, SoSearchAction, and SoWriteAction. |
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This virtual method can be overridden to execute code after the scene graph traversal. Default method does nothing. Reimplemented in SoGLRenderAction. |
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Set the termination flag. Typically set to TRUE from nodes upon special conditions being met during scene graph traversal -- like the correct node being found when doing SoSearchAction traversal or when grabbing the event from an SoHandleEventAction.
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Returns a list of the elements used by action instances of this class upon traversal operations. |
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This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. |
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This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. This method not available in the original OIV API, see SoSubAction.h for explanation. |
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This API member is considered internal to the library, as it is not likely to be of interest to the application programmer. This method not available in the original OIV API, see SoSubAction.h for explanation. |
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Pointer to the traversal state instance of the action. |
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Stores the list of "nodetype to actionmethod" mappings for the particular action instance. |