VOID Bound::Merge( const Bound& Other )
{
Sphere OtherSphere;
OtherSphere.Center = Other.GetCenter();
OtherSphere.Radius = Other.GetMaxRadius();
if( m_Type == Bound::No_Bound )
{
SetSphere( OtherSphere );
return;
}
Sphere ThisSphere;
if( m_Type != Bound::Sphere_Bound )
{
// convert this bound into a sphere
ThisSphere.Center = GetCenter();
ThisSphere.Radius = GetMaxRadius();
}
else
{
ThisSphere = GetSphere();
}
XMVECTOR vThisCenter = XMLoadFloat3( &ThisSphere.Center );
XMVECTOR vOtherCenter = XMLoadFloat3( &OtherSphere.Center );
XMVECTOR vThisToOther = XMVectorSubtract( vOtherCenter, vThisCenter );
XMVECTOR vDistance = XMVector3LengthEst( vThisToOther );
FLOAT fCombinedDiameter = XMVectorGetX( vDistance ) + ThisSphere.Radius + OtherSphere.Radius;
if( fCombinedDiameter <= ( ThisSphere.Radius * 2 ) )
{
SetSphere( ThisSphere );
return;
}
if( fCombinedDiameter <= ( OtherSphere.Radius * 2 ) )
{
SetSphere( OtherSphere );
return;
}
XMVECTOR vDirectionNorm = XMVector3Normalize( vThisToOther );
XMVECTOR vRadius = XMVectorSet( ThisSphere.Radius, OtherSphere.Radius, 0, 0 );
XMVECTOR vThisRadius = XMVectorSplatX( vRadius );
XMVECTOR vOtherRadius = XMVectorSplatY( vRadius );
XMVECTOR vCombinedDiameter = vThisRadius + vDistance + vOtherRadius;
XMVECTOR vMaxDiameter = XMVectorMax( vCombinedDiameter, vThisRadius * 2 );
vMaxDiameter = XMVectorMax( vMaxDiameter, vOtherRadius * 2 );
XMVECTOR vMaxRadius = vMaxDiameter * 0.5f;
ThisSphere.Radius = XMVectorGetX( vMaxRadius );
vMaxRadius -= vThisRadius;
XMVECTOR vCombinedCenter = vThisCenter + vMaxRadius * vDirectionNorm;
XMStoreFloat3( &ThisSphere.Center, vCombinedCenter );
SetSphere( ThisSphere );
}
//-----------------------------------------------------------------------------
// Compute the intersection of a ray (Origin, Direction) with an axis aligned
// box using the slabs method.
//-----------------------------------------------------------------------------
BOOL GLibIntersectRayAxisAlignedBox( FXMVECTOR Origin, FXMVECTOR Direction, const XNA::AxisAlignedBox* pVolume, FLOAT* pDist )
{
XMASSERT( pVolume );
XMASSERT( pDist );
//XMASSERT( XMVector3IsUnit( Direction ) );
static const XMVECTOR Epsilon =
{
1e-20f, 1e-20f, 1e-20f, 1e-20f
};
static const XMVECTOR FltMin =
{
-FLT_MAX, -FLT_MAX, -FLT_MAX, -FLT_MAX
};
static const XMVECTOR FltMax =
{
FLT_MAX, FLT_MAX, FLT_MAX, FLT_MAX
};
// Load the box.
XMVECTOR Center = XMLoadFloat3( &pVolume->Center );
XMVECTOR Extents = XMLoadFloat3( &pVolume->Extents );
// Adjust ray origin to be relative to center of the box.
XMVECTOR TOrigin = Center - Origin;
// Compute the dot product againt each axis of the box.
// Since the axii are (1,0,0), (0,1,0), (0,0,1) no computation is necessary.
XMVECTOR AxisDotOrigin = TOrigin;
XMVECTOR AxisDotDirection = Direction;
// if (fabs(AxisDotDirection) <= Epsilon) the ray is nearly parallel to the slab.
XMVECTOR IsParallel = XMVectorLessOrEqual( XMVectorAbs( AxisDotDirection ), Epsilon );
// Test against all three axii simultaneously.
XMVECTOR InverseAxisDotDirection = XMVectorReciprocal( AxisDotDirection );
XMVECTOR t1 = ( AxisDotOrigin - Extents ) * InverseAxisDotDirection;
XMVECTOR t2 = ( AxisDotOrigin + Extents ) * InverseAxisDotDirection;
// Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
// use the results from any directions parallel to the slab.
XMVECTOR t_min = XMVectorSelect( XMVectorMin( t1, t2 ), FltMin, IsParallel );
XMVECTOR t_max = XMVectorSelect( XMVectorMax( t1, t2 ), FltMax, IsParallel );
// t_min.x = maximum( t_min.x, t_min.y, t_min.z );
// t_max.x = minimum( t_max.x, t_max.y, t_max.z );
t_min = XMVectorMax( t_min, XMVectorSplatY( t_min ) ); // x = max(x,y)
t_min = XMVectorMax( t_min, XMVectorSplatZ( t_min ) ); // x = max(max(x,y),z)
t_max = XMVectorMin( t_max, XMVectorSplatY( t_max ) ); // x = min(x,y)
t_max = XMVectorMin( t_max, XMVectorSplatZ( t_max ) ); // x = min(min(x,y),z)
// if ( t_min > t_max ) return FALSE;
XMVECTOR NoIntersection = XMVectorGreater( XMVectorSplatX( t_min ), XMVectorSplatX( t_max ) );
// if ( t_max < 0.0f ) return FALSE;
NoIntersection = XMVectorOrInt( NoIntersection, XMVectorLess( XMVectorSplatX( t_max ), XMVectorZero() ) );
// if (IsParallel && (-Extents > AxisDotOrigin || Extents < AxisDotOrigin)) return FALSE;
XMVECTOR ParallelOverlap = XMVectorInBounds( AxisDotOrigin, Extents );
NoIntersection = XMVectorOrInt( NoIntersection, XMVectorAndCInt( IsParallel, ParallelOverlap ) );
if(!GLibXMVector3AnyTrue( NoIntersection ) )
{
// Store the x-component to *pDist
XMStoreFloat( pDist, t_min );
return TRUE;
}
return FALSE;
}
