Fix activateItem always having the same rotation (#3840)

* Use bot rotation for use_item packet

* Add test for activateItem rotation in use_item packet

Verifies that bot.activateItem() sends the bot's current yaw and pitch
(converted via toNotchianYaw/toNotchianPitch) in the use_item packet's
rotation field. Skips on protocol versions before 1.21.1 where the
rotation field does not exist.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Add external test for activateItem rotation

Verifies that activateItem sends the bot's actual yaw/pitch in the
use_item packet by intercepting the outgoing packet and checking the
rotation values match expected Notchian angles for two different
look directions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude <claude@anthropic.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: SuperGamerTron

lib/plugins/inventory.js

@@ -1,6 +1,7 @@
 const assert = require('assert')
 const { Vec3 } = require('vec3')
 const { once, sleep, createDoneTask, createTask, withTimeout } = require('../promise_utils')
+const { toNotchianYaw, toNotchianPitch } = require('../conversions')
 
 module.exports = inject
 
@@ -128,7 +129,10 @@ function inject (bot, { hideErrors }) {
       bot._client.write('use_item', {
         hand: offHand ? 1 : 0,
         sequence,
-        rotation: { x: 0, y: 0 }
+        rotation: {
+          x: toNotchianYaw(bot.entity.yaw),
+          y: toNotchianPitch(bot.entity.pitch)
+        }
       })
     }
   }

test/externalTests/activateItem.js

@@ -0,0 +1,76 @@
+const assert = require('assert')
+
+module.exports = () => async (bot) => {
+  const Item = require('prismarine-item')(bot.registry)
+
+  // Test that activateItem sends the bot's actual rotation (PR #3840).
+  // Only applies to versions that use the 'use_item' packet with rotation.
+  if (!bot.supportFeature('useItemWithOwnPacket')) return
+
+  await bot.test.becomeCreative()
+  await bot.test.clearInventory()
+
+  const snowballItem = bot.registry.itemsByName.snowball
+  if (!snowballItem) return
+
+  // Give the bot a snowball and switch to survival to throw it
+  await bot.test.setInventorySlot(36, new Item(snowballItem.id, 16, 0))
+  await bot.test.becomeSurvival()
+  await bot.test.wait(250)
+
+  // Look south (+Z direction): yaw = PI, pitch = 0
+  await bot.look(Math.PI, 0, true)
+  await bot.test.wait(250)
+
+  // Intercept the outgoing use_item packet to verify rotation
+  const sentPacket = await new Promise((resolve) => {
+    const origWrite = bot._client.write
+    bot._client.write = function (name, data) {
+      origWrite.apply(bot._client, arguments)
+      if (name === 'use_item') {
+        bot._client.write = origWrite
+        resolve(data)
+      }
+    }
+    bot.activateItem()
+  })
+
+  // Verify the rotation was sent (not zeros)
+  assert(sentPacket.rotation, 'use_item packet should have rotation field')
+  const { x: sentYaw, y: sentPitch } = sentPacket.rotation
+
+  // With pitch = 0, the notchian pitch should be ~0
+  assert(Math.abs(sentPitch) < 1, `Pitch should be near 0 for level look, got ${sentPitch}`)
+
+  // With yaw = PI (south), the notchian yaw should be ~0 (due to toNotchianYaw = degrees(PI - yaw))
+  // toNotchianYaw(PI) = degrees(PI - PI) = 0
+  assert(Math.abs(sentYaw) < 1, `Yaw should be near 0 for south-facing look, got ${sentYaw}`)
+
+  // Now test a different direction: look east (yaw = PI/2 in mineflayer)
+  await bot.look(Math.PI * 3 / 2, -0.5, true)
+  await bot.test.wait(250)
+
+  const sentPacket2 = await new Promise((resolve) => {
+    const origWrite = bot._client.write
+    bot._client.write = function (name, data) {
+      origWrite.apply(bot._client, arguments)
+      if (name === 'use_item') {
+        bot._client.write = origWrite
+        resolve(data)
+      }
+    }
+    bot.activateItem()
+  })
+
+  const { x: sentYaw2, y: sentPitch2 } = sentPacket2.rotation
+
+  // toNotchianYaw(3*PI/2) = degrees(PI - 3*PI/2) = degrees(-PI/2) = -90
+  assert(Math.abs(sentYaw2 - (-90)) < 1, `Yaw should be near -90 for east-facing look, got ${sentYaw2}`)
+
+  // toNotchianPitch(-0.5) = degrees(0.5) ≈ 28.65
+  const expectedPitch = (0.5 * 180) / Math.PI
+  assert(Math.abs(sentPitch2 - expectedPitch) < 1, `Pitch should be near ${expectedPitch}, got ${sentPitch2}`)
+
+  await bot.test.becomeCreative()
+  await bot.test.clearInventory()
+}

test/internalTest.js

@@ -1282,5 +1282,53 @@ for (const supportedVersion of mineflayer.testedVersions) {
         }
       })
     })
+
+    describe('activateItem rotation', () => {
+      it('should send the bot rotation in the use_item packet', function (done) {
+        // The rotation field in use_item was added in 1.21.1
+        const useItemFields = registry.protocol?.play?.toServer?.types?.packet_use_item?.[1]
+        const hasRotation = useItemFields && useItemFields.some(f => f.name === 'rotation')
+        if (!hasRotation) {
+          this.skip()
+          return
+        }
+        const { toNotchianYaw, toNotchianPitch } = require('../lib/conversions')
+        const testYaw = 1.5
+        const testPitch = -0.3
+        server.on('playerJoin', async (client) => {
+          await client.write('login', bot.test.generateLoginPacket())
+          await client.write('position', {
+            x: 0,
+            y: 66,
+            z: 0,
+            dx: 0,
+            dy: 0,
+            dz: 0,
+            yaw: 0,
+            pitch: 0,
+            flags: bot.registry.version['>=']('1.21.3') ? {} : 0,
+            teleportId: 0
+          })
+
+          client.on('packet', (data, meta) => {
+            if (meta.name === 'use_item') {
+              const expectedYaw = toNotchianYaw(testYaw)
+              const expectedPitch = toNotchianPitch(testPitch)
+              assert.ok(data.rotation, 'use_item packet should have rotation field')
+              assert.ok(Math.abs(data.rotation.x - expectedYaw) < 0.001,
+                `Expected yaw ${expectedYaw}, got ${data.rotation.x}`)
+              assert.ok(Math.abs(data.rotation.y - expectedPitch) < 0.001,
+                `Expected pitch ${expectedPitch}, got ${data.rotation.y}`)
+              done()
+            }
+          })
+
+          await sleep(100)
+          bot.entity.yaw = testYaw
+          bot.entity.pitch = testPitch
+          bot.activateItem()
+        })
+      })
+    })
   })
 }