/**-------------------------------------------------------------------------------
build_hull
Building the hull consists of two procedures: building the lower and
then the upper hull. The two procedures are nearly identical - the main
difference between the two is the test for convexity. When building the upper
hull, our rule is that the middle point must always be *above* the line formed
by its two closest neighbors. When building the lower hull, the rule is that point
must be *below* its two closest neighbors. We pass this information to the
building routine as the last parameter, which is either -1 or 1.
@brief
@return std::vector<Ogre::Vector3>
---------------------------------------------------------------------------------*/
std::vector<Ogre::Vector3> ConvexHullGraham::build_hull()
{
build_half_hull(mLowerPartitionPoints, mLowerHull, 1);
build_half_hull(mUpperPartitionPoints, mUpperHull, -1);
std::vector<Ogre::Vector3> ret;
for (size_t i = 0 ; i < mLowerHull.size() ; i++)
{
ret.push_back(mLowerHull[i]);
}
for (std::vector<Ogre::Vector3>::reverse_iterator ii = mUpperHull.rbegin() + 1;
ii != mUpperHull.rend(); ++ii)
{
ret.push_back(*ii);
}
return ret;
}
//
// Building the hull consists of two procedures: building the lower
// and then the upper hull. The two procedures are nearly identical -
// the main difference between the two is the test for convexity. When
// building the upper hull, our rull is that the middle point must
// always be *above* the line formed by its two closest
// neighbors. When building the lower hull, the rule is that point
// must be *below* its two closest neighbors. We pass this information
// to the building routine as the last parameter, which is either -1
// or 1.
//
void GrahamScan::build_hull()
{
build_half_hull(lower_partition_points, lower_hull, 1 );
build_half_hull(upper_partition_points, upper_hull, -1 );
}