SoSurroundScale(3)

NAME
SoSurroundScale - The SoSurroundScale class is used to automatically scale geometry to surround other geometry.

This node calculates a transformation (a translation and a scale) which will, when the node is traversed, be appended to the current model matrix, making a default cube placed directly to the right of this node in the graph surround geometry to the right of the container branch this node is on. The container is specified by the field SoSurroundScale::numNodesUpToContainer.

SYNOPSIS

#include <Inventor/nodes/SoSurroundScale.h>

Inherits SoTransformation.

  Public Member Functions
virtual SoType getTypeId (void) const
SoSurroundScale (void)
void invalidate (void)
virtual void doAction (SoAction *action)
void setDoingTranslations (const SbBool val)
SbBool isDoingTranslations (void)

  Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass (void)

  Public Attributes
SoSFInt32 numNodesUpToContainer
SoSFInt32 numNodesUpToReset

  Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoSurroundScale ()
virtual void callback (SoCallbackAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void getMatrix (SoGetMatrixAction *action)
virtual void pick (SoPickAction *action)
void updateMySurroundParams (SoAction *action, const SbMatrix &inv)
void setIgnoreInBbox (const SbBool val)
SbBool isIgnoreInBbox (void)

  Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)

  Protected Attributes
SbVec3f cachedScale
SbVec3f cachedInvScale
SbVec3f cachedTranslation
SbBool cacheOK
SbBool doTranslations

  Additional Inherited Members

Detailed Description

The SoSurroundScale class is used to automatically scale geometry to surround other geometry.

This node calculates a transformation (a translation and a scale) which will, when the node is traversed, be appended to the current model matrix, making a default cube placed directly to the right of this node in the graph surround geometry to the right of the container branch this node is on. The container is specified by the field SoSurroundScale::numNodesUpToContainer. When calculating the bounding box to be surrounded, the bounding box action will be applied to the container node, and the bounding box calculations will be reset after traversing the node specified by the field SoSurroundScale::numNodesUpToReset.

A way of thinking of the container node is that there exists a path from the root-node to the SoSurroundScale node. This path has a number of nodes in it. numNodesUpToContainer is the number of nodes in the path from the SoSurroundScale node towards the root node. When having counted numNodesUpToContainer from the SoSurroundScale node, you will have reached the container node. The container node is the seed-node that the bounding box is calculated from. All nodes lower than the seed-node will be a part of the bounding box unless they are closer to the SoSurroundScale node than numNodesUpToReset.

To make sure the node(s) that are to be scaled by the SoSurroundScale node aren't a part of the bounding box, the numNodesUpToReset is used. It is also the number of nodes up from the SoSurroundScale node towards the root node. The meaning of numNodesUpToReset is that nodes that are closer to the SoSurroundNode than the node at position numNodesUpToReset are not to be used for bounding box calculations.

Here's a complete, stand-alone example which sets up an SoTrackballDragger (connected to a cube), and uses an SoSurroundScale node to make it auto-scale to the size of the high cube and translates it an offset to one side of the cube:

#include <Inventor/Qt/SoQt.h>
#include <Inventor/Qt/viewers/SoQtExaminerViewer.h>
#include <Inventor/draggers/SoTrackballDragger.h>
#include <Inventor/nodes/SoAntiSquish.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoCube.h>
#include <Inventor/nodes/SoSurroundScale.h>
#include <Inventor/nodes/SoRotation.h>
#include <Inventor/nodes/SoTranslation.h>
int
main(int argc, char **argv)
{
  QWidget * window = SoQt::init(argv[0]);
  if (window == NULL) exit(1);
  SoSeparator * root = new SoSeparator;
  root->ref();
  SoSeparator * surroundsep = new SoSeparator;
  root->addChild(surroundsep);
  SoTranslation * translation = new SoTranslation;
  translation->translation = SbVec3f(12, 0, 0);
  surroundsep->addChild(translation);
  SoSurroundScale * ss = new SoSurroundScale;
  ss->numNodesUpToReset = 1;
  ss->numNodesUpToContainer = 2;
  surroundsep->addChild(ss);
  SoAntiSquish * antisquish = new SoAntiSquish;
  antisquish->sizing = SoAntiSquish::BIGGEST_DIMENSION;
  surroundsep->addChild(antisquish);
  SoTrackballDragger * dragger = new SoTrackballDragger;
  surroundsep->addChild(dragger);
  SoRotation * rotation = new SoRotation;
  rotation->rotation.connectFrom(& dragger->rotation);
  root->addChild(rotation);
  SoCube * cube = new SoCube;
  cube->height = 10.0f;
  root->addChild(cube);
  SoQtExaminerViewer * viewer = new SoQtExaminerViewer(window);
  viewer->setSceneGraph(root);
  viewer->setViewing(FALSE);
  viewer->setDecoration(FALSE);
  viewer->show();
  SoQt::show(window);
  SoQt::mainLoop();
  delete viewer;
  root->unref();
  return 0;
}

It might be easier to see how the SoSurroundScale node works in the above example by looking at the actual scenegraph:

#Inventor V2.1 ascii
Separator {
   Separator {
      Translation {
         translation 12 0 0
      }
      SurroundScale {
         numNodesUpToContainer 2
         numNodesUpToReset 1
      }
      AntiSquish {
         sizing BIGGEST_DIMENSION
      }
      DEF mydragger TrackballDragger {
      }
   }
   Rotation {
      rotation 0 0 1  0 =
      USE mydragger . rotation
   }
   Cube {
      height 10
   }
}

This node is internally used by manipulators to make it possible for them to scale their dragger's geometry to match the scenegraph geometry it is modifying, as is demonstrated above (but outside of the context of a manipulator).

It is also generally useful for application programmers who want any particular piece of geometry surround other geometry of unknown or changing extent.

SoSurroundScale nodes in the scenegraph are often paired up with SoAntiSquish nodes to get uniform scaling along all three principal axes, as has also been done in the above example.

FILE FORMAT/DEFAULTS:

SurroundScale {
    numNodesUpToContainer 0
    numNodesUpToReset 0
}

See also:
    SoAntiSquish

Constructor & Destructor Documentation

  SoSurroundScale::SoSurroundScale (void)
Constructor.

  SoSurroundScale::~SoSurroundScale () [protected], [virtual]
Destructor.

Member Function Documentation

  SoType SoSurroundScale::getTypeId (void) const [virtual]
Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting.

Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: 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 for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Reimplemented from SoTransformation.

  const SoFieldData * SoSurroundScale::getFieldData (void) const [protected], [virtual]
Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoTransformation.

  void SoSurroundScale::invalidate (void)
Invalidates the cached transformation, forcing a recalculation to be done the next time this node is traversed.

  void SoSurroundScale::doAction (SoAction * action) [virtual]
This function performs the typical operation of a node for any action.

Reimplemented from SoNode.

  void SoSurroundScale::setDoingTranslations (const SbBool val)
Sets whether the translation part of the transformation should be ignored or not. Default behavior is to translate.

  SbBool SoSurroundScale::isDoingTranslations (void)
Returns whether the translation part of the transformation should be ignored or not.

See also:
    setDoingTranslations()

  void SoSurroundScale::callback (SoCallbackAction * action) [protected], [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 SoNode.

  void SoSurroundScale::GLRender (SoGLRenderAction * action) [protected], [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 SoNode.

  void SoSurroundScale::getBoundingBox (SoGetBoundingBoxAction * action) [protected], [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 SoNode.

  void SoSurroundScale::getMatrix (SoGetMatrixAction * action) [protected], [virtual]
Action method for SoGetMatrixAction.

Updates action by accumulating with the transformation matrix of this node (if any).

Reimplemented from SoNode.

  void SoSurroundScale::pick (SoPickAction * action) [protected], [virtual]
Action method for SoPickAction.

Does common processing for SoPickAction action instances.

Reimplemented from SoNode.

  void SoSurroundScale::updateMySurroundParams (SoAction * action, const SbMatrix & inv) [protected]
Calculates the translation and scale needed to make a default cube surround geometry to the right of the branch this node is on.

  void SoSurroundScale::setIgnoreInBbox (const SbBool val) [protected]
Sets whether bounding box calculations in SoGetBoundingBoxAction should be affected by this node.

Default is to ignore our bounding box calculations.

  SbBool SoSurroundScale::isIgnoreInBbox (void) [protected]
Returns the value of the flag that decides whether bounding box calculations in SoGetBoundingBoxAction should be affected by this node.

See also:
    setIgnoreInBbox()

Member Data Documentation

  SoSFInt32 SoSurroundScale::numNodesUpToContainer
Number of nodes in the path counting from this and 'upwards' to the container node.

  SoSFInt32 SoSurroundScale::numNodesUpToReset
Number of nodes in the path counting from this and 'upwards' to the node where we will reset the bounding box value.

  SoSurroundScale::cachedScale [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  SoSurroundScale::cachedInvScale [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  SoSurroundScale::cachedTranslation [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  SoSurroundScale::cacheOK [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

  SoSurroundScale::doTranslations [protected]
This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Author

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