//----------------------------------------------------------------------------
Box2 Mgc::ContOrientedBox (int iQuantity, const Vector2* akPoint)
{
Box2 kBox;
GaussPointsFit(iQuantity,akPoint,kBox.Center(),kBox.Axes(),
kBox.Extents());
// Let C be the box center and let U0 and U1 be the box axes. Each input
// point is of the form X = C + y0*U0 + y1*U1. The following code
// computes min(y0), max(y0), min(y1), and max(y1). The box center is
// then adjusted to be
// C' = C + 0.5*(min(y0)+max(y0))*U0 + 0.5*(min(y1)+max(y1))*U1
Vector2 kDiff = akPoint[0] - kBox.Center();
Real fY0Min = kDiff.Dot(kBox.Axis(0)), fY0Max = fY0Min;
Real fY1Min = kDiff.Dot(kBox.Axis(1)), fY1Max = fY1Min;
for (int i = 1; i < iQuantity; i++)
{
kDiff = akPoint[i] - kBox.Center();
Real fY0 = kDiff.Dot(kBox.Axis(0));
if ( fY0 < fY0Min )
fY0Min = fY0;
else if ( fY0 > fY0Max )
fY0Max = fY0;
Real fY1 = kDiff.Dot(kBox.Axis(1));
if ( fY1 < fY1Min )
fY1Min = fY1;
else if ( fY1 > fY1Max )
fY1Max = fY1;
}
kBox.Center() += (0.5f*(fY0Min+fY0Max))*kBox.Axis(0) +
(0.5f*(fY1Min+fY1Max))*kBox.Axis(1);
kBox.Extent(0) = 0.5f*(fY0Max - fY0Min);
kBox.Extent(1) = 0.5f*(fY1Max - fY1Min);
return kBox;
}
//----------------------------------------------------------------------------
bool Mgc::ContOrientedBox (int iQuantity, const Vector2* akPoint,
const bool* abValid, Box2& rkBox)
{
if ( !GaussPointsFit(iQuantity,akPoint,abValid,rkBox.Center(),
rkBox.Axes(),rkBox.Extents()) )
{
return false;
}
// Let C be the box center and let U0 and U1 be the box axes. Each input
// point is of the form X = C + y0*U0 + y1*U1. The following code
// computes min(y0), max(y0), min(y1), and max(y1). The box center is
// then adjusted to be
// C' = C + 0.5*(min(y0)+max(y0))*U0 + 0.5*(min(y1)+max(y1))*U1
// get first valid vertex
Vector2 kDiff;
Real fY0Min, fY0Max, fY1Min, fY1Max;
int i;
for (i = 0; i < iQuantity; i++)
{
if ( abValid[i] )
{
kDiff = akPoint[i] - rkBox.Center();
fY0Min = kDiff.Dot(rkBox.Axis(0));
fY0Max = fY0Min;
fY1Min = kDiff.Dot(rkBox.Axis(1));
fY1Max = fY1Min;
break;
}
}
for (i++; i < iQuantity; i++)
{
if ( abValid[i] )
{
kDiff = akPoint[i] - rkBox.Center();
Real fY0 = kDiff.Dot(rkBox.Axis(0));
if ( fY0 < fY0Min )
fY0Min = fY0;
else if ( fY0 > fY0Max )
fY0Max = fY0;
Real fY1 = kDiff.Dot(rkBox.Axis(1));
if ( fY1 < fY1Min )
fY1Min = fY1;
else if ( fY1 > fY1Max )
fY1Max = fY1;
}
}
rkBox.Center() += (0.5f*(fY0Min+fY0Max))*rkBox.Axis(0)
+ (0.5f*(fY1Min+fY1Max))*rkBox.Axis(1);
rkBox.Extent(0) = 0.5f*(fY0Max - fY0Min);
rkBox.Extent(1) = 0.5f*(fY1Max - fY1Min);
return true;
}