Hi Dusten -- The short answer (probably) is that you should look at
osg::TriangleFunctor.
The longer answer:
I'm currently developing an open source library containing utilities for
integrating OSG with Bullet. Here is the code I use to create triangle
meshes. The code for ComputeTriMeshVisitor is attached.
btTriangleMeshShape* osgBullet::btTriMeshCollisionShapeFromOSG( osg::Node*
node )
{
ComputeTriMeshVisitor visitor;
node->accept( visitor );
osg::Vec3Array* vertices = visitor.getTriMesh();
if( vertices->size() < 3 )
{
osg::notify( osg::WARN ) << "osgBullet::btTriMeshCollisionShapeFromOSG,
no triangles found" << std::endl;
return( NULL );
}
btTriangleMesh* mesh = new btTriangleMesh;
for( size_t i = 0; i + 3 < vertices->size(); i += 3 )
{
osg::Vec3& p1 = ( *vertices )[ i ];
osg::Vec3& p2 = ( *vertices )[ i + 1 ];
osg::Vec3& p3 = ( *vertices )[ i + 2 ];
mesh->addTriangle( btVector3( p1.x(), p1.y(), p1.z() ),
btVector3( p2.x(), p2.y(), p2.z() ),
btVector3( p3.x(), p3.y(), p3.z() ) );
}
btBvhTriangleMeshShape* meshShape = new btBvhTriangleMeshShape( mesh, true
);
return( meshShape );
}
I hope this is helpful. I'll post more info here when I make this code
publically available.
Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com
+1 303 859 9466
/*
*
* Copyright (c) 2008 Blue Newt Software LLC and Skew Matrix Software LLC.
* All rights reserved.
*
*/
#ifndef OSGBULLET_COMPUTETRIMESHVISITOR
#define OSGBULLET_COMPUTETRIMESHVISITOR 1
#include <osg/Array>
#include <osg/NodeVisitor>
namespace osgBullet {
/* TBD Consider using OSG localtoworld method instead of keeping a matrix
stack. */
class ComputeTriMeshVisitor
: public osg::NodeVisitor
{
public:
ComputeTriMeshVisitor( osg::NodeVisitor::TraversalMode traversalMode =
TRAVERSE_ALL_CHILDREN );
virtual void reset();
osg::Vec3Array * getTriMesh()
{
return( mesh.get() );
}
void apply( osg::Node & node );
void apply( osg::Transform & transform );
void apply( osg::Geode & geode );
inline void pushMatrix( osg::Matrix & matrix )
{
stack.push_back( matrix );
}
inline void popMatrix()
{
stack.pop_back();
}
void applyDrawable( osg::Drawable * drawable );
protected:
typedef std::vector< osg::Matrix > MatrixStack;
MatrixStack stack;
osg::ref_ptr< osg::Vec3Array > mesh;
};
}
#endif
/*
*
* Copyright (c) 2008 Blue Newt Software LLC and Skew Matrix Software LLC.
* All rights reserved.
*
*/
#include <osg/Transform>
#include <osg/Drawable>
#include <osg/Geode>
#include <osg/PrimitiveSet>
#include <osg/TriangleFunctor>
#include <osgBullet/ComputeTriMeshVisitor.h>
#include <iostream>
using namespace osgBullet;
using namespace osg;
struct ComputeTriMeshFunc
{
ComputeTriMeshFunc()
{
vertices = new osg::Vec3Array;
vertices->clear();
}
void inline operator()( const osg::Vec3 v1, const osg::Vec3 v2, const
osg::Vec3 v3, bool _temp )
{
vertices->push_back( v1 );
vertices->push_back( v2 );
vertices->push_back( v3 );
}
osg::ref_ptr< osg::Vec3Array > vertices;
};
ComputeTriMeshVisitor::ComputeTriMeshVisitor( osg::NodeVisitor::TraversalMode
traversalMode )
: osg::NodeVisitor( traversalMode )
{
stack.push_back( osg::Matrix::identity() );
mesh = new osg::Vec3Array;
}
void ComputeTriMeshVisitor::reset()
{
stack.clear();
stack.push_back( osg::Matrix::identity() );
mesh->clear();
}
void ComputeTriMeshVisitor::apply( osg::Node & node )
{
traverse( node );
}
void ComputeTriMeshVisitor::apply( osg::Transform & transform )
{
osg::Matrix matrix;
matrix = stack.back();
transform.computeLocalToWorldMatrix( matrix, this );
pushMatrix( matrix );
traverse( transform );
popMatrix();
}
void ComputeTriMeshVisitor::apply( osg::Geode & geode )
{
for( unsigned int i = 0; i < geode.getNumDrawables(); ++i )
{
applyDrawable( geode.getDrawable( i ) );
}
}
void ComputeTriMeshVisitor::applyDrawable( osg::Drawable * drawable )
{
osg::TriangleFunctor< ComputeTriMeshFunc > functor;
drawable->accept( functor );
for( osg::Vec3Array::iterator iter = functor.vertices->begin();
iter != functor.vertices->end(); ++iter )
{
osg::Matrix & matrix = stack.back();
mesh->push_back( *iter * matrix );
}
}
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