Player-World Interaction #

Digging a node #

Preconditions are a node somewhere in the map. This node is pointable, has a selection box and can be dug by the hand or the tool the player is wielding. The player has interact priv and the tool has a tool range that the node can be pointed. The node is not stuck somewhere the player can’t point it.

• First look at the node, it becomes pointed_thing.

  Note that on android the node is pointed without looking (referring to the cross position) at it.

• Then LMB is pressed down while holding an item which does not have on_use.

  If LMB wasn’t released before, a click happens, which causes a punch event.

  • The client send a punch event (client->interact(4, pointed), see game.cpp:3657 (28.02.2017)).

  • On server side the punch event is passed to mods, see on_punch and the deprecated register_on_punchnode.

  Then the client sends the digging start event to the server (interact(0, pointed), game.cpp:3948).

  • The server uses this information for anticheat measurements.

• Now continue looking at the node, i.e. keep pointing it, and hold down LMB.

  Periodically client-side: Crack animation is updated, digging particles are spawned (if not disabled in the settings) and the node dig sound is played.

  • The dig sound is either the “dig” field in the “sounds” table in the nodedef

  • or, if it’s not present, the client uses the sound “default_dig_${groupname}” (file name extension omitted here), where $groupname is one of the groups the node has, see (game.cpp:4001), and gain is set to 0.5.

  • The default_dig_ thing should be banned from source code in my opinion.

• Some time later, when the digging time elapsed,

  the client sends a digging completion event to the server (interact(2, pointed), game.cpp:4018),

  the node disappears client-side,

  more particles are spawned (if enabled) and

  the dug sound is played.

• Now the server recieves the digging completion event.

  Anticheat probably, e.g due to lag, thinks the player dug the node too fast.

  • dug_too_fast cheat is passed to mods, see register_on_cheat, and digging aborts.

  If the nodedef has a can_dig function, it’s executed and probably stops the digging.

  The on_dig function in the nodedef is called now.

  • The default on_dig function problably removes the node:

    • The on_destruct is executed, air is set and after_destruct is executed.

  • And probably (the same probably as before) it then calls the after_dig_node function in the nodedef if present.