Minetest Forums

See Clonk's callbacks for insipration

Currently, Minetest has on_activate, on_step, on_punch, and on_rightclick.

Additional callbacks that are useful are:

• on_collide_node(dir) - When an entity hits a wall. Useful for projectiles (arrows, or bombs that explode on contact). dir = collision direction (bottom, north, top, ...)
• on_collide_object(obj) - When an entity touches/hits another entity. Only for entities with physical = true. Useful for projectiles.
• on_remove() - When an entity is removed. (by object:remove or by the engine (as in too many objects))
• on_death() - When an entity dies. (by obj:punch or obj:set_hp)
• on_deactivate() - Opposite of activate
• on_create() - Maybe this is redundant

In the current state of the engine, these (except on_remove) can be done in Lua, by adding code into the on_step function (on_punch for on_death). But it is better (and faster) if these are called by the engine, because the calculations are already done by the engine.

PS
Another thing I wish to be added to the engine

• get_standing() - Whether the entity is on the ground. Very useful for mobs code.

Sounds very useful. on_collide_node could be used for all those pressure plates out there.

I had this idea too

You can probably use the function "get_staticdata" as if it was the opposite of "on_activate".
The string that on_activate receives as parameter is the same that get_staticdata returns. get_staticdata gets called when the entity deactivates (unloads) and the string is saved so that the state of the entity can be restored when its received by on_activate.

Collision callbacks have been requested in the past.. I also suggested it, but it's not simple to implement, specially without lag.

+1

+1

Ferk wrote:You can probably use the function "get_staticdata" as if it was the opposite of "on_activate".
The string that on_activate receives as parameter is the same that get_staticdata returns. get_staticdata gets called when the entity deactivates (unloads) and the string is saved so that the state of the entity can be restored when its received by on_activate.

AFAIK get_staticdata gets called every time the map is saved. There is no distinction between map save and unloading.

YES!!

Found this whilst looking for collision detection, this would be really good!

I'm thinking of trying my hand at coding these in C++. A few of them would be very useful, for the new mobs framework I'm developing (in fact, that's the reason I stumbled across this threat). I can certainly attest that detecting object-vs-object collisions is really hacky atm -- even though the engine collects this information :/