koobas.hobune.stream
How can I check if a point(Vector3) is in Matrix4x4
I'm placing random objects in an imaginary cube in front of my target. I am using following code to do this:
var center = Vector3.zero;
center.z = (m_size.z / 2) + m_offset.z;
center.x += m_offset.x;
center.y += m_offset.y;
var mat = Matrix4x4.TRS(m_target.position, m_target.rotation, m_target.lossyScale);
Vector3 pos = center + new Vector3(Random.Range(-m_size.x / 2, m_size.x / 2), Random.Range(-m_size.y / 2, m_size.y / 2), Random.Range(-m_size.z / 2, m_size.z / 2));
pos = mat.MultiplyPoint(pos);
m_instantiatedObject.Add(Instantiate(m_object, pos, Quaternion.identity));
And it's working as expected. but now my problem is as my target moves, the previously placed objects may not be in this imaginary cube anymore. how can I check if my placed objects are in this imaginary cube and if they are not I can remove them?
Best Answer
"Undo" the transformation by multilying with the inverse of the matrix (mat.inverse) and check if the result is inside your reference cube. To check if a point is in an axis aligned cube, you either just check all vector conponents by yourself or you can use the Bounds struct to do it for you:
pos = mat.inverse.MultiplyPoint(pos);
if (!new Bounds(center, m_size).Contains(pos)) {
// do some stuff
}
