Body parts, energy swirls and NBT in expressions

Apoli 1.85.0 and Origins 1.38.0. This one is mostly about bodies: where a hit lands on one, how to move half of one at a time, and how to make one glow.

Where did that hit land?#

The new apoli:body_part damage condition passes when the damage hit a particular part of the body — the head, an arm, the chest, the back of a foot. It drops into every damage condition field, so a headshot bonus is an ordinary apoli:modify_damage_dealt power:

{
  "type": "apoli:modify_damage_dealt",
  "damage_condition": {
    "type": "apoli:body_part",
    "body_part": "head",
    "require_hit_data": true
  },
  "modifier": {
    "operation": "multiply_total",
    "amount": 1
  }
}

Arrows and other projectiles are traced along their flight path, a player’s swing follows where they are looking, and a mob’s swing comes in at its own height, so a silverfish bites your feet. The trace runs against the target’s body in the pose it is actually in — crouched, swimming, drawing a bow, or laid out flat by a modify_model_parts power — which is what separates it from a fixed height band: a crouching player’s head is not where a standing player’s is. Damage with no direction, like fall damage, is routed by the #apoli:body_part/... damage type tags, which packs can extend.

If you are coming from Sync’s Body Part Damage Modifier: that power is a modify_damage_taken per region with this condition in it, and the condition page has the multiple-region version written out. Turn on dev mode and every hit is reported in chat, which makes tuning a region quick.

Moving half a body#

apoli:modify_model_parts has five new part names: arms, legs, upper, lower and whole. A group moves as one piece around the joint that holds it on — the arms around the line between the shoulders, the upper body around the waist, the whole model around the feet — so a pitch on upper is a bow from the waist rather than a head, torso and two arms each tipping over on their own. A new pivot field puts the joint anywhere else.

The group names work everywhere a body part is named: model_color tints them, custom_model_render restricts an overlay to them, and particles anchor between the limbs. Every one of those names now comes from one list, documented on the new Body Part page, along with regions such as hands, chest and achilles_heel.

Energy swirls#

apoli:custom_model_render has a new render type, energy_swirl — the charged creeper’s aura — with a scroll_speed to set how fast it drifts. Texture overlays also draw on any living entity now, not only players, so a zombie can glow too. The old apoli:energy_swirl id loads as this power with the swirl already configured, so packs that used it work as they are.

Enchantments and NBT in expressions#

Two new expression functions read what is in an entity’s hands and data:

"amount": "10 + enchantment[minecraft:mending, weapon.mainhand, sum]"

reads an enchantment level from a slot, the armour, both hands or all equipment, summed or maxed like the apoli:enchantment condition. And nbt[...] reads a number the way /data get does — from the entity, an item slot, a block entity, a command storage, or the other side of a bi-entity action, with sum, max, min and count for paths that match more than one value:

"amount": "nbt[Inventory[{id:\"minecraft:arrow\"}].count, sum]"

Unknown body parts in the new condition, and malformed ranges, are load errors on every version of the game rather than quietly matching every hit.