How to High-Light a Vega Object

#include "vg.h"          // Required for the standard Vega classes
#include "vgperf.h"      // Required for the vgGetXXXPfNode functions
#include "pf.h"          // Required for the standard Performer classes
#include "vgutil.h"
#include "pfutil.h"      // Required for pfFindNode

// Declare the Pre and Post Node Draw as STATIC these have to be static

static int highlightPreDrawTravFunc ( pfTraverser *trav, void *data );

static int highlightPostDrawTravFunc ( pfTraverser *trav, void *data );

static int remhighlightPostDrawTravFuncFIX( pfTraverser *trav, void *data);

pfHighlight* createHighlight( const float r ,const float g ,const float b ,const unsigned int fill );

void remHighlightFromVegaObject( vgObject *object );

void setHighlightOnVegaObject ( vgObject *object );

pfHighlight*

createHighlight( const float r

,const float g

,const float b

,const unsigned int fill ) {

// ####################################################

// # Public function

// #

// # Create a and return a new pfHighlight instance

// #

// # Note it is upto the caller to manage the deletion

// # of this instance

// #

// ####################################################

// create the new blank highlight instance

pfHighlight *hlight = pfNewHlight( vgGetSharedArena());

// Set the fill/ out line mode for the highlight

// The following are possible high style note thatsome may not supported

// on all platforms, also note that the style can be or'd together

// to form combinations of high lights

// See the Performer PGuide and man pages for further details

// PFHL_LINES PFHL_LINES_R

// PFHL_LINESPAT PFHL_LINESPAT2

// PFHL_LINESMASK PFHL_FILL

// PFHL_FILLPAT PFHL_FILLPAT2

// PFHL_FILLTEX PFHL_FILL_R

// PFHL_FILLMASK PFHL_SKIP_BASE

// PFHL_POINTS PFHL_NORMALS

// PFHL_BBOX_LINES PFHL_BBOX_FILL

pfHlightMode( hlight, fill ) ;

// Set the forground and background color for the highlight

pfHlightColor( hlight, PFHL_FGCOLOR, r, g, b );

pfHlightColor( hlight, PFHL_BGCOLOR, r, g, b );

// Set the alpha to opaque as transparent is not supported

// on many systems

pfHlightAlpha( hlight, 1.0f );

// Set the line width for line styles

pfHlightLineWidth( hlight, 1 .0f);

// When showing normals make them short

pfHlightNormalLength( hlight, 0.5f, 0.0f );

return hlight;

} // createHighlight

int

highlightPreDrawTravFunc( pfTraverser *trav, void *data){

// ####################################################

// #

// # STATIC Function: (PFTRAV_DRAW)

// #

// # Pre Draw traversal function placed on a node which

// # enables and applies the highlight to the node and

// # all the nodes children

// #

// # note this function MUST be declared as STATIC

// #

// ####################################################

// We need to first save the current Performer State

pfPushState();

// Now we can enable the highlighting

pfEnable( PFEN_HIGHLIGHTING );

// Now retrieve the highlight from the passed user data

pfHighlight *hlight = (pfHighlight *)data;

// If we have a highlight then make it current

if( hlight)

pfApplyHlight( hlight );

// We need to tell Performer to continue the traverse of this node

return (PFTRAV_CONT);

} // highlightPreDrawTravFunc

int

highlightPostDrawTravFunc( pfTraverser *trav, void *data){

// ######################################################

// #

// # STATIC Function: (PFTRAV_DRAW)

// #

// # Post Draw traversal function on a node which disables

// # the highlight applied in the corresponding pre draw

// # fucntion

// #

// # note this function MUST be declared as STATIC

// #

// ######################################################

// Now we disable the highlighting we enabled

pfDisable( PFEN_HIGHLIGHTING );

// And restore the Performer state

pfPopState();

// We need to tell Performer to continue the traverse of this node

return (PFTRAV_CONT);

} // highlightPostDrawTravFunc

int

remhighlightPostDrawTravFuncFIX( pfTraverser *trav, void *data){

// #################################################################

// #

// # STATIC Function: (PFTRAV_DRAW)

// #

// # Post Draw traversal function on a node which disables

// # the highlight applied in the corresponding pre draw

// # fucntion

// #

// # This should be added in the remove highligh function

// # because when pfNodeTravFuncs( node, PFTRAV_DRAW, NULL, NULL )

// # called the call backs are removed but an apparent bug in Vega

// # means that the Predraw gets applied but the post draw function

// # does not and the highlight stays on this fixes the problem by

// # explicitly disbaling the highlighitng

// #

// # note this function MUST be declared as STATIC

// #

// #################################################################

// Now we disable the highlighting we enabled

pfDisable( PFEN_HIGHLIGHTING );

// Retrieve which node we are

pfNode *node = pfGetTravNode( trav );

// We only need to call this one so we can self remove

pfNodeTravFuncs( node, PFTRAV_DRAW, NULL, NULL);

// We need to tell Performer to continue the traverse of this node

return (PFTRAV_CONT);

} // remhighlightPostDrawTravFuncFIX

void

setHighlightOnVegaObject( vgObject *object ){

// ##########################################################

// #

// # Public Function

// #

// # Example of how to add Highlightinh to a Vega Object

// #

// ##########################################################

// Sanity check we need a object

if( object == NULL )

return;

// Get the root Performer node of the object

pfNode *node = vgGetObjPfNode( object );

if( node == NULL )

return;

// Create the Highlight instance, Red and Filled

pfHighlight *hlight = createHighlight( 1.0f, 0.0f, 0.0f, PFHL_FILL);

if( hlight == NULL )

return;

// Set the Pre and Post draw callback which enable and disable the highlight

pfNodeTravFuncs( node, PFTRAV_DRAW, highlightPreDrawTravFunc, highlightPostDrawTravFunc );

// Set the highlight instance as the user data for the callbacks

pfNodeTravData( node, PFTRAV_DRAW, hlight );

} //setHighlightOnVegaObject

void

remHighlightFromVegaObject( vgObject *object ){

// ##########################################################

// #

// # Public Function

// #

// # Remove the highlight Callbacks from the passed object

// #

// ##########################################################

// Sanity check we need a object

if( object == NULL )

return;

// Get the root Performer node of the object

pfNode *node = vgGetObjPfNode( object );

if( node == NULL )

return;

// Retrieve the highlight instance from the user data

pfHighlight *hlight = (pfHighlight *)pfGetNodeTravData( node, PFTRAV_DRAW );

// Remove the highlight call back functions by simply setting

// them to NULL on the Node, Performer only supports one call

// pre and post traversal callbacks per node

pfNodeTravFuncs( node, PFTRAV_DRAW, NULL, NULL);

// Theres an apperent bug in Vega where the Highlight will stay on

// becuase the removal of the draw function gets called with the

// highlight enabled but the post never gets called to remove the

// highlight, so the state is wrong this is a work around that will

// ensure that the highlight is removed

pfNodeTravFuncs( node, PFTRAV_DRAW, NULL, remhighlightPostDrawTravFuncFIX);

// And remove the data simply by

pfNodeTravData( node, PFTRAV_DRAW, NULL );

// If we got a highlight back from the user data

// then we delete it

if( hlight != NULL )

pfDelete( hlight);

} // remHighlightFromVegaObject

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