26.2 Vacuum and Phase Shifting

🧲 Vacuum Movement & Phase Shifting (MC 26.2)

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Feature Infobox	Technical Parameters
System Class	net.instantgratification.magnet.MagnetMovement
Trigger Event	Server Player Tick (PlayerMixin $\rightarrow$ MagnetManager.tick)
Default Pull Range	12 blocks (ig:magnet_range)
Default Terminal Speed	80% ($0.8\text{ blocks/tick} = 16.0\text{ m/s}$)
Default Acceleration	10% ($0.10\text{ lerp factor/tick}$)
Phase Shifting (NoClip)	Enabled (ig:magnet_noclip = true)
Target Vector	Player Eye Position (player.getEyePosition())
Ground Offset Boost	$+0.05\text{ m}$ on Y-axis when entity.onGround()

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📖 System Overview

The core vacuum mechanic in Magnet, Let me get that! scans for dropped ItemEntity instances within the player's configured radius each server tick and pulls them toward the player's eye level using smooth non-linear interpolation.

To prevent items from snagging on cobblestone lip edges, tree canopies, or ore vein crevices, the mod activates Phase Shifting (NoClip), allowing items in flight to pass harmlessly through solid block voxels.

+-------------+      Line-of-Sight OK      +----------------------+      Lerp Velocity Applied      +------------------+
| Item Entity | -------------------------> | Set NoClip (2 Ticks) | ------------------------------> | Player Eye Pos   |
+-------------+                            +----------------------+                                 +------------------+
                                                      |
                                                      v
                                           [Cancel Wall Pushout]
                                           [Bypass Block Collide]
                                           [Cancel In-Wall Grav]

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🧮 Physics & Vector Mathematics

When pulling an item, the trajectory is computed directly in 3D Euclidean space:

1. Vector to Target

Let $\vec{p}{\text{entity}} = (x_e, y_e, z_e)$ be the item's current position, and $\vec{p}{\text{eye}} = (x_p, y_p + h_{\text{eye}}, z_p)$ be the player's eye position. $$\vec{v}{\text{target}} = \vec{p}{\text{eye}} - \vec{p}{\text{entity}}$$ $$\hat{d} = \frac{\vec{v}{\text{target}}}{|\vec{v}{\text{target}}|} = \frac{\vec{v}{\text{target}}}{\sqrt{\Delta x^2 + \Delta y^2 + \Delta z^2}}$$

2. Desired Terminal Velocity

The target velocity vector scales unit direction $\hat{d}$ by the configured speed parameter: $$\text{Speed Scalar } s = \frac{\text{GameRule}(\text{ig:magnet_speed})}{100.0}$$ $$\vec{u}_{\text{target}} = \hat{d} \times s$$ At default setting ($80%$), $s = 0.8\text{ blocks/tick}$. At $20\text{ ticks/s}$, terminal velocity is $16.0\text{ m/s}$.

3. Non-Linear Acceleration (Lerp)

Velocity is updated using linear interpolation (Vec3.lerp) based on acceleration factor $a$: $$\text{Acceleration Factor } a = \frac{\text{GameRule}(\text{ig:magnet_acceleration})}{100.0}$$ $$\vec{v}{\text{new}} = \vec{v}{\text{current}} + (\vec{u}{\text{target}} - \vec{v}{\text{current}}) \times a$$

4. Ground Anti-Friction Boost

If the item rests on a block surface (entity.onGround() == true), ground friction is instantly broken to prevent floor dragging:

if (entity.onGround()) {
    entity.setOnGround(false);
    entity.setPos(entity.position().add(0, 0.05, 0));
}

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🧱 Phase Shifting (NoClip Engine)

When ig:magnet_noclip is enabled, items are tagged with a 2-tick NoClip window:

1. State Activation: ((IMagnetEntity) entity).ig_magnet$setMagnetNoClip() sets noClipTicks = 2.
2. Move Hijacking (MixinEntity.java):
   • move(MoverType, Vec3): @Inject(at = @At("HEAD")) saves originalNoPhysics and forces entity.noPhysics = true.
   • move(MoverType, Vec3): @Inject(at = @At("RETURN")) restores entity.noPhysics = originalNoPhysics.
3. Pushout Cancellation: @Inject(method = "moveTowardsClosestSpace", at = @At("HEAD"), cancellable = true) prevents vanilla block pushout code from aggressively ejecting items out of blocks.
4. Conditional Gravity Cancellation: @Inject(method = "applyGravity", at = @At("HEAD"), cancellable = true) cancels downward gravity only when the item is physically intersecting a block voxel (!level.noCollision(...)), preserving natural arc trajectories in open air.

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⚙️ Relevant Configuration & GameRules

GameRule	Type	Default	Unit / Range	Description
ig:magnet_enabled	Boolean	true	true/false	Master toggle for all vacuum logic.
ig:magnet_range	Integer	12	1..64 blocks	Maximum spherical vacuum radius.
ig:magnet_speed	Integer	80	1..1000%	Terminal velocity percentage ($80 = 0.8\text{ b/t}$).
ig:magnet_acceleration	Integer	10	1..1000%	Pull acceleration percentage ($10 = 10%\text{ lerp/tick}$).
ig:magnet_noclip	Boolean	true	true/false	Enables block phase shifting during pull.

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🔗 Related Wiki Documentation

• Line-of-Sight & Obstacle Penetration
• Instant Pickup Mode
• Architecture & Mixin Implementations
• Return to MC 26.2 Portal