Accurate Projectile Trajectory Preview

Ever wondered where your arrow, snowball, or potion will land? This mod provides a visual preview of projectile trajectories, similar to PTP, but with improved prediction accuracy and no multiplayer limitations.

🔎 Features

• Trajectory Visualization: Displays the expected path of your projectile before launching.
• Target Highlighting: Trajectory color indicates a higher likelihood of hitting a target.

⚠️ Limitations and Notes

• Minecraft projectile physics include random spread offsets, so the actual impact position may slightly differ from the preview.
• However, trajectory prediction is designed to be more precise than the original PTP implementation.

🔬 Technical Changes Compared to Original PTP

• This fork modifies both the simulation logic and multiplayer behavior:

Multiplayer behavior

• Removed the server handshake check (serverHasMod)

• Removed networking validation logic

• Trajectory preview is now always available client-side (no server requirement)

Simulation changes

1. Removed projectileInfo.order-based update system The original implementation updated motion using a configurable order array. This fork replaces it with a fixed per-tick update sequence:

• position update

• drag application

• gravity application

This makes motion simulation consistent and closer to vanilla projectile behavior.

2. Reworked entity collision handling

• Reduced broad-phase AABB inflation from 1.0 to 0.3

• Added distance-based spread-aware entity hit detection

• Added a “guaranteed hit” detection flag when the ray intersects the true bounding box

3. Improved spread simulation

• Added distance-based spread offset:

spreadOffset = normalizedVelocity * (distanceFromStart * maxSpreadFactor)

• Adjusted spread multiplier from * 3.0 to * 2.0

• Spread is now simulated dynamically per step instead of being approximated

4. Refined water physics handling

• More explicit switching between normal drag/gravity and underwater values

• Applied consistently during simulation loop

5. Minor stability improvements

• Early velocity zero-check (vel.lengthSqr() < 1e-8)

• Added startPos tracking for spread calculation

📦 Modpacks

Feel free to include this mod in your modpacks.