/*@brief Return the dot product between two vectors */
public static float btDot( ref btVector3 v1, ref btVector3 v2 )
{
return v1.dot( ref v2 );
}
/// Solve A * x = b, where b is a column vector. This is more efficient
/// than computing the inverse in one-shot cases.
///Solve33 is from Box2d, thanks to Erin Catto,
public void solve33( ref btVector3 b, out btVector3 result )
{
btVector3 col1 = getColumn( 0 );
btVector3 col2 = getColumn( 1 );
btVector3 col3 = getColumn( 2 );
btVector3 tmp;
col2.cross( ref col3, out tmp );
float det = col1.dot( ref tmp );
if( btScalar.btFabs( det ) > btScalar.SIMD_EPSILON )
{
det = 1.0f / det;
}
col2.cross( ref col3, out tmp );
result.x = det * b.dot( ref tmp );
b.cross( ref col3, out tmp );
result.y = det * col1.dot( ref tmp );
col2.cross( ref b, out tmp );
result.z = det * col1.dot( ref tmp );
result.w = 0;
}
/*@brief Return a rotated version of this vector
@param wAxis The axis to rotate about
@param angle The angle to rotate by */
public void rotate( ref btVector3 wAxis, float angle, out btVector3 result )
{
btVector3 o;
wAxis.Mult( wAxis.dot( ref this ), out o );
btVector3 _x;
this.Sub( ref o, out _x );
btVector3 _y;
wAxis.cross( ref this, out _y );
btVector3 tmp;
btVector3 tmp2;
_x.Mult( btScalar.btCos( angle ), out tmp );
o.Add( ref tmp, out tmp2 );
_y.Mult( btScalar.btSin( angle ), out tmp );
tmp2.Add( ref tmp, out result );
}