Allow rotating entity selectionboxes (#12379)

doc/lua_api.txt

@@ -1609,6 +1609,8 @@ Exact pointing location (currently only `Raycast` supports these fields):
 * `pointed_thing.intersection_normal`: Unit vector, points outwards of the
   selected selection box. This specifies which face is pointed at.
   Is a null vector `vector.zero()` when the pointer is inside the selection box.
+  For entities with rotated selection boxes, this will be rotated properly
+  by the entity's rotation - it will always be in absolute world space.
 
 
 
@@ -7075,6 +7077,8 @@ child will follow movement and rotation of that bone.
 * `set_rotation(rot)`
     * `rot` is a vector (radians). X is pitch (elevation), Y is yaw (heading)
       and Z is roll (bank).
+    * Does not reset rotation incurred through `automatic_rotate`.
+      Remove & readd your objects to force a certain rotation.
 * `get_rotation()`: returns the rotation, a vector (radians)
 * `set_yaw(yaw)`: sets the yaw in radians (heading).
 * `get_yaw()`: returns number in radians
@@ -7554,6 +7558,22 @@ It can be created via `Raycast(pos1, pos2, objects, liquids)` or
 * `liquids`: if false, liquid nodes (`liquidtype ~= "none"`) won't be
              returned. Default is false.
 
+### Limitations
+
+Raycasts don't always work properly for attached objects as the server has no knowledge of models & bones.
+
+**Rotated selectionboxes paired with `automatic_rotate` are not reliable** either since the server
+can't reliably know the total rotation of the objects on different clients (which may differ on a per-client basis).
+The server calculates the total rotation incurred through `automatic_rotate` as a "best guess"
+assuming the object was active & rotating on the client all the time since its creation.
+This may be significantly out of sync with what clients see.
+Additionally, network latency and delayed property sending may create a mismatch of client- & server rotations.
+
+In singleplayer mode, raycasts on objects with rotated selectionboxes & automatic rotate will usually only be slightly off;
+toggling automatic rotation may however cause errors to add up.
+
+In multiplayer mode, the error may be arbitrarily large.
+
 ### Methods
 
 * `next()`: returns a `pointed_thing` with exact pointing location
@@ -7670,11 +7690,15 @@ Player properties need to be saved manually.
         collide_with_objects = true,
         -- Collide with other objects if physical = true
 
-        collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
-        selectionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
-        -- Selection box uses collision box dimensions when not set.
-        -- For both boxes: {xmin, ymin, zmin, xmax, ymax, zmax} in nodes from
-        -- object position.
+        collisionbox = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5 },  -- default
+        selectionbox = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5, rotate = false },
+		-- { xmin, ymin, zmin, xmax, ymax, zmax } in nodes from object position.
+        -- Collision boxes cannot rotate, setting `rotate = true` on it has no effect.
+        -- If not set, the selection box copies the collision box, and will also not rotate.
+        -- If `rotate = false`, the selection box will not rotate with the object itself, remaining fixed to the axes.
+        -- If `rotate = true`, it will match the object's rotation and any attachment rotations.
+        -- Raycasts use the selection box and object's rotation, but do *not* obey attachment rotations.
+        
 
         pointable = true,
         -- Whether the object can be pointed at