koobas.hobune.stream
What's the difference between transform.position + offset and transform.TransformPoint(offset)
I was working a the whole day on a bug where two seemingly identical positions weren't identical at all.
Turns out that transform.position + offset and transform.TransformPoint(offset) return two different things, even when the scales are all the same.
What's the difference?
Here's my whole code:
GameObject obj = new GameObject();
obj.transform.parent = transform;
obj.transform.localPosition = new Vector3(objOffset.x, objSize.y / 2, objOffset.y);
obj.transform.localRotation = Quaternion.Euler(0f, objRotation, 0f);
Matrix4x4 cubeTransform = Matrix4x4.TRS(
transform.TransformPoint(new Vector3(objOffset.x, objSize.y / 2, objOffset.y)),
//transform.position + new Vector3(objOffset.x, objSize.y / 2, objOffset.y), // why doesnt this work ??
transform.rotation * Quaternion.Euler(0f, objRotation, 0f),
transform.lossyScale);
Matrix4x4 old = Gizmos.matrix;
Gizmos.matrix *= cubeTransform;
Gizmos.color = Color.black;
Gizmos.DrawWireCube(Vector3.zero, new Vector3(objSize.x, 0, objSize.z));
Gizmos.matrix = old;
transform.position + offset
involves two points in world space and returns a point in the world space. An example would be a camera in an RTS where the camera hovers the target regardless of target's rotation.
transform.TransformPoint(offset)
involves a single point in space and a single point in LOCAL space (according to transform) and returns a point in world space. An example would be a camera in a third person shooter. The camera is always placed behind the shoulder of the player and moves according to the player's rotation.
