🏮 Phototaxis & Nighttime Light Orbiting
| Parameter | Specification Details |
|---|---|
| AI Goal Class | net.vanillaoutsider.betterbats.ai.BatHuntLightGoal |
| Detection Light Level | Block Light > 8 (LIGHT_DETECT_THRESHOLD) |
| Continue Light Level | Block Light > 6 (LIGHT_CONTINUE_THRESHOLD) |
| Search Radius | 10 blocks (Deterministic BlockPos.findClosestMatch) |
| Search Throttle | Executes light search once every 30 ticks (~1.5s) |
| Orbit Duration | 200 to 600 ticks ($10 - 30\text{ seconds}$) |
| Goal Cooldown | 200 to 400 ticks ($10 - 20\text{ seconds}$) |
| Approach Mode | Curved banking flight vector ($d > 2.5\text{ blocks}$) |
| Orbiting Mode | Tangential velocity vector with sine-wave vertical bobbing |
| Visual Particles | CRIT (10% tick probability during orbit) |
🌙 Phototaxis (The Moth Effect)
At night (!level.isBrightOutside()), bats display positive phototaxis, attracting them to artificial block light sources such as torches, lanterns, campfire embers, and glowstone.
Rather than orbiting a single lantern forever, bats operate on a Moth Effect cycle: they seek a nearby lantern, bank towards it, orbit in a gentle bobbing motion for 10–30 seconds, and then trigger a 10–20 second cooldown before hopping to another nearby light source or returning to high flight.
┌──────────────────────────┐
│ Nighttime Ambient │
└────────────┬─────────────┘
│
Scans 10 blocks for Block Light > 8
│
Light Found (targetLight)?
┌──────────┴──────────┐
YES NO
│ │
Distance > 2.5 blocks? Wander / BOIDs
┌─────┴─────┐
YES NO
│ │
Curved Banking Tangential Orbit
Approach Flight + Sine Bobbing (sin(t * 0.15) * 0.03)
+ CRIT Particles
│ │
└─────┬─────┘
│
Ticks >= maxCirclingTicks? (10-30s)
│
Cooldown 10-20s -> Hop to next light📐 Flight Vector Math
1. Curved Banking Approach ($d > 2.5\text{ blocks}$)
To prevent rigid straight-line movement, the approach velocity blends the direct direction vector with a perpendicular tangent vector:
$$\mathbf{V}{\text{tangent}} = (-dz, \ dx) \cdot 0.5$$ $$\mathbf{V}{\text{steer}} = \frac{(dx, dz) + \mathbf{V}_{\text{tangent}}}{\sqrt{dx^2 + dz^2}} \cdot 0.12$$
2. Tangential Orbiting & Vertical Sine Bobbing ($d \le 2.5\text{ blocks}$)
Once within 2.5 blocks of the light center, the bat calculates a perpendicular cross-product vector for smooth circular orbiting, combined with a vertical sine-wave oscillation:
$$\text{Y}{\text{bobbing}} = \sin(\text{circlingTicks} \times 0.15) \times 0.03$$ $$\mathbf{V}{\text{final}} = \left( (V_x + \text{Cross}x \cdot S) \times 0.9, \ V_y \times 0.9 + \text{Y}{\text{bobbing}}, \ (V_z + \text{Cross}_z \cdot S) \times 0.9 \right)$$