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; }