Minecraft Tutorial Line Of Sight

Tutorial: Datapack Example — Sight Magic

Java Edition only; requires 1.21.2+ (the raycast tutorial it builds on is the base). Prerequisites: the raycasting tutorial, datapack/resourcepack tutorials.

Goal

Right-clicking an item causes events at the block the player is looking at:

• an explosion, and
• if the target is a beehive or bee nest, print the counts of adult and baby bees inside.

Raycast Improvements

The base raycast (generic/function/raycast/) is enhanced:

• Step length 0.5 instead of 0.1 (fewer recursions).
• #raycast_check_times counter vs #raycast_max_check_times (max 1000) → return run function generic:raycast/end.
• Stop when the block at ~ ~ ~ is not #generic:raycast/can_pass.
• Entity check at ~ ~-0.5 ~ with @n[dx=0,dy=0,dz=0]-style tiny box (flag #raycast_pass_entity).
• Start from the executor's eye position: execute as @s anchored eyes run ....
• Optional debugging: particle minecraft:end_rod ~ ~ ~ 0 0 0 0 0; interaction entity execute positioned ~ ~-0.5 ~ run summon interaction ^ ^ ^ {Tags:["test","source_entity"]}.

Right-Click Detection

A minecraft:consume_item advancement fires only when the consumed item matches a custom_data predicate ({listen_event:'right_click'}), and rewards a function:

{
  "criteria": {
    "generic:right_click_event": {
      "trigger": "minecraft:consume_item",
      "conditions": { "item": { "predicates": { "custom_data": "{listen_event:'right_click'}" } } }
    }
  },
  "rewards": { "function": "generic:event/right_click" }
}

generic/function/event/right_click.mcfunction revokes the advancement, then simulates a coroutine: store the executor and its held item (e.g. into a storage or a marker entity), wait 1 tick, then restore the item so it is not actually consumed (the consume_item trigger fires before the stack is truly eaten).

Sight Explosion Magic

Explosion at the aim point: summon an instant-igniting TNT or a Creeper at the ray end.

• generic/tags/function/right_click.json — function-tag interface: { "values": ["test:sight_magic/extender/right_click"] }.
• test/sight_magic/extender/right_click.mcfunction — implements the interface:
  • Guard: execute unless items entity @s weapon.mainhand * [custom_data ~ {id:'sight_magic'}] run return fail.
  • Domain flag pair: tag @s add used_sight_magic ... tag @s remove used_sight_magic (closed around the branch).
  • Branch by held item: execute if items entity @s weapon.mainhand * [custom_data ~ {cause_event:'explosion'}] run function test:sight_magic/explosion/start.
• explosion/start — tags the player, sets #raycast_max_check_times, calls the raycast; explosion/end (via the raycast end interface) summons the TNT/Creeper at ~ ~ ~ and cleans up.

Bee Finder Magic

Same skeleton, new branch: cause_event:'get_bees' → test:sight_magic/bee_finder/start.

• start: tag @s add get_bees, set raycast max checks, run raycast.
• end: check the block at the ray end — if it is beehive/bee_nest, read the block entity with /data get block ~ ~ ~ bees and count entries; adult vs baby by each bee's entity_data.Age (-1 = baby); output e.g. tellraw @a "Adults: X, Babies: Y". Clean up tags and counters.

Carrot-on-a-Stick Toggle (optional, older pattern)

Scoreboard-based toggle for using carrot-on-a-stick as a "remote":

• nuke:entities/player: execute as @s[scores={nukeUseCSt=1..}] at @s run function nuke:use_carrot_on_a_stick/type.
• type: checks weapon.mainhand / weapon.offhand for carrot_on_a_stick, dispatches to mainhand/offhand functions, then scoreboard players reset @s nukeUseCSt.
• mainhand/offhand: check carrot_on_a_stick {id:'nuke:remote'} custom data to enable the effect, else the plain carrot-on-a-stick behavior (pig riding); toggling sets the score. (Note: this section is flagged as outdated for current versions — prefer the consume_item advancement approach.)