Hi all,

I'm new to modding (although not to java) and I'm trying to make a player who holds a certain item be able to fly in survival mode. I've done my best to look this issue up, but everything I'm finding, even on this forum, seems to be outdated, except for the way I've done it, which doesn't seem to be working. The player is not able to fly even when holding the item. I even took a look at the source for the curseforge Angel Ring mod and It seems to use the same method to enable flight.

Here's the event listener I'm using:

@SubscribeEvent
    public static void honorbladePowers(TickEvent.PlayerTickEvent e) {

        if (e.player.getItemInHand(InteractionHand.MAIN_HAND).getItem() instanceof ShardbladeItem) {
            e.player.getAbilities().mayfly = true;
            e.player.onUpdateAbilities();

        } else {
            e.player.getAbilities().mayfly = false;
            e.player.onUpdateAbilities();

        }
    }

 

 

 

Any help as to why enabling mayfly and then calling onUpdateAbilities() isn't working would be awesome! Thanks y'all!

 

Edited November 3, 20222 yr by JFuller
Remove accidental dox lol

That way of doing it is very inefficient. The PlayerTick event is called on the client and server at both the start and end of each tick.

You should be checking event.side and event.phase to limit when you do things.

The onUpdateAbilities() sends a network packet to the other side.

So, your code would be sending 4 network packets per player per tick.

 

Here's a more efficient way:

@Mod.EventBusSubscriber(modid = MODID)
public class Events {

    @SubscribeEvent
    public static void equipmentChange(LivingEquipmentChangeEvent event) {
        if (event.getEntity() instanceof Player player && event.getSlot() == EquipmentSlot.OFFHAND) {
            // WARNING: Proof of concept code not the correct logic
            player.getAbilities().mayfly = event.getTo().is(Items.DIAMOND);
            player.onUpdateAbilities();
        }
    }
}

That event only happens on the server and only when the equipment actually changes.

The above works for me, using diamonds in the shield slot as my trigger.

 

WARNING. The above logic is not complete.

One example is, it would remove flight from creative mode players when they remove the diamond. 

Another is it doesn't set flying=false when the diamonds are removed.

Edited November 3, 20222 yr by warjort

3 hours ago, warjort said:

That way of doing it is very inefficient. The PlayerTick event is called on the client and server at both the start and end of each tick.

You should be checking event.side and event.phase to limit when you do things.

The onUpdateAbilities() sends a network packet to the other side.

So, your code would be sending 4 network packets per player per tick.

 

Here's a more efficient way:

@Mod.EventBusSubscriber(modid = MODID)
public class Events {

    @SubscribeEvent
    public static void equipmentChange(LivingEquipmentChangeEvent event) {
        if (event.getEntity() instanceof Player player && event.getSlot() == EquipmentSlot.OFFHAND) {
            // WARNING: Proof of concept code not the correct logic
            player.getAbilities().mayfly = event.getTo().is(Items.DIAMOND);
            player.onUpdateAbilities();
        }
    }
}

That event only happens on the server and only when the equipment actually changes.

The above works for me, using diamonds in the shield slot as my trigger.

 

WARNING. The above logic is not complete.

One example is, it would remove flight from creative mode players when they remove the diamond. 

Another is it doesn't set flying=false when the diamonds are removed.

Thank you so much! I spent a long time on google initially and for some reason I couldn't find the event that triggers when you swap equipment lol. That will make this much easier!