[Plib-devel] ssgBranch with pre and post draw callbacks

[Eric E. <Eri...@fr...>]

Hello,

I have a small modification to submit for plib-ssg. This consists in
allowing the call of the pre and post draw callbacks for branches and
not only for leaves.

I use this in TORCS to modify parameters not managed by ssgSimpleState,
but from an object point of vue, because when an object is loaded from a
modeler, it is painful to traverse the sub-tree for adding redundant
pre and post callbacks to all the leaves.

Here are the modifications:

file ssgBranch.cxx:

void ssgBranch::cull ( sgFrustum *f, sgMat4 m, int test_needed )
{
  int cull_result = cull_test ( f, m, test_needed ) ;

  if ( cull_result == SSG_OUTSIDE )
    return ;

  for ( ssgEntity *e = getKid ( 0 ) ; e != NULL ; e = getNextKid() )
    e -> cull ( f, m, cull_result != SSG_INSIDE ) ;
}

becomes:

void ssgBranch::cull ( sgFrustum *f, sgMat4 m, int test_needed )
{
    int cull_result = cull_test ( f, m, test_needed ) ;
    
    if ( cull_result == SSG_OUTSIDE )
	return ;
	    
    if ( preDrawCB != NULL && ! (*preDrawCB)(this) )
	return ;
	    
    for ( ssgEntity *e = getKid ( 0 ) ; e != NULL ; e = getNextKid() )
	e -> cull ( f, m, cull_result != SSG_INSIDE ) ;
	    
    if ( postDrawCB != NULL )
	(*postDrawCB)(this) ;
}

For the current version I use a derived version of ssgBranch to manage
the GL_TEXTURE_GEN_[ST] states for env mapping and the glTexEnvf calls
to display the textures in different manners.

Eric.
--
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                       TORCS
            The Open Racing Car Simulator
                 http://torcs.org

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