// explicit btMatrix3x3(stringbtScalar m) { setFromOpenGLSubMatrix(m); }
/*@brief Constructor from Quaternion */
public btMatrix3x3( ref btQuaternion q )
{
//setRotation( q );
float d = q.length2();
//btFullAssert(d != (float)(0.0));
float s = btScalar.BT_TWO / d;
float xs = q.x * s, ys = q.y * s, zs = q.z * s;
float wx = q.w * xs, wy = q.w * ys, wz = q.w * zs;
float xx = q.x * xs, xy = q.x * ys, xz = q.x * zs;
float yy = q.y * ys, yz = q.y * zs, zz = q.z * zs;
m_el0.x = btScalar.BT_ONE - ( yy + zz ); m_el0.y = xy - wz; m_el0.z = xz + wy; m_el0.w = 0;
m_el1.x = xy + wz; m_el1.y = btScalar.BT_ONE - ( xx + zz ); m_el1.z = yz - wx; m_el1.w = 0;
m_el2.x = xz - wy; m_el2.y = yz + wx; m_el2.z = btScalar.BT_ONE - ( xx + yy ); m_el2.w = 0;
m_el3.x = 0; m_el3.y = 0; m_el3.z = 0; m_el3.w = 1;
}
public static void setRotation( out btMatrix3x3 result, ref btQuaternion q )
{
float d = q.length2();
#if PARANOID_ASSERTS
Debug.Assert( d != 0 );
#endif
float s = btScalar.BT_TWO / d;
float xs = q.x * s, ys = q.y * s, zs = q.z * s;
float wx = q.w * xs, wy = q.w * ys, wz = q.w * zs;
float xx = q.x * xs, xy = q.x * ys, xz = q.x * zs;
float yy = q.y * ys, yz = q.y * zs, zz = q.z * zs;
btMatrix3x3.setValue( out result,
btScalar.BT_ONE - ( yy + zz ), xy - wz, xz + wy,
xy + wz, btScalar.BT_ONE - ( xx + zz ), yz - wx,
xz - wy, yz + wx, btScalar.BT_ONE - ( xx + yy ) );
}