Introduction

Anti Esp is an advanced but lightweight server side mod for modern fabric that allows server owners to combat visual cheats such as X-ray, chest esp, entity esp, block esp and freecam; protecting information such as ore locations, base locations, structure locations, etc.

Why Anti Esp?

Moderating a survival server on fabric has always been difficult due to the lack of moderation tools. This mod was inspired by Raycasted Anti Esp - a plugin for paper, folia, spigot, bukkit and purpur. With no current support for fabric, I decided to make one from scratch.

Config file

A config file will be generated automatically for you once you reboot the server after adding the mod. File manager --> config --> anti esp.toml

Examples

hide_block_entities = true

Hide containers such as chests and furnaces, along with signs, spawners, vaults, sculk sensors, sculk shriekers and any other block entities.

extra_hidden_blocks = ["minecraft:gold_block"]

Allows you to add vanilla or modded blocks to protect. Gold blocks are included by default. More blocks can be added, separate each value with a comma.

A simple, generic base at stone level

!A simple, generic base at stone level

The same base, viewed by a different player using freecam cheats

!The same base, viewed by a different player using freecam cheats

Anti esp off

!Anti esp off - esp from a popular hack client revealing a trial chamber.

Anti esp on

!Anti esp & anti freecam on - Esp completely blocked, hiding the trial chamber

Core functionality

Anti Esp

Every tick, the server draws ray lines from the players hitbox, checking for direct line of sight to a protected block. Once direct line of sight is recorded/predicted, the server then sends block/entity information to the client. Anti esp also predicts future movements to reveal protected blocks early to reduce the chance of data being sent to the client late.

Anti freecam

Anti esp plays the core role in preventing freecam too, however another way we combat freecam is not sending chunk data to the client below a certain Y level. This hides all chunk data below that Y level (0 by default), preventing freecam from seeing beyond that. This is good for protecting bases from esp and freecam.

Anti xray

Uses the exact same architecture as anti esp as it's all the same - except ores only obfuscate when fully enclosed by solid blocks, hiding ore veins but not exposed ores by default, reducing pop ins. To make sure data isn't sent late, ore veins monitor their surrounding blocks for any changes such as block movement or destruction - which tells an ore to send data to the client. Connected ores of the same type always send all their data at once, reducing extra, resource heavy calculations.

Extra information

Block protection

Rewrites chunk and block update packets sent to the client, replacing protected blocks with 'fake' alternative blocks to blend in ordinary terrain or other preset blocks when sampling isn't available. It also surpresses block entity data such as chest data.

Visibility checks

Uses voxel based ray traversal, or DDA, through loaded chunks. Only full, opaque and non fluid blocks count as cover. This cover triggers the obfuscation of protected blocks and entities. Transparent blocks, fluid block or half blocks do not trigger obfuscation. Movement prediction, corner checks, surrounding block states and visibility grace help to eliminate pop ins (note that server lag, or high latency connections, may cause information to be sent to the client late)

Entity protection

Hooks into entity tracking to control whether entity information is sent to the client such as model, held items and applied effects. Players uses stricter visibility checks.

Underground mask (anti freecam)

Hides everything from structures, to mobs, to biome data; from the client below a certain Y level. This is only enabled in the overworld by default. This removes all chunk data below this configurable Y level from being sent to the client, the fundamental part of stopping freecam and esp cheats from locating bases and structures. The default is Y: 0 and I don't recommend increasing it. Chunk data will be sent to the client once advanced movement prediction tells the server that their is only air/liquid/half blocks separating the player from Y: 0, sending the information.

Performance controls

Uses cached results, priority queues and tick budgets. Protected projectile entities such as enderpearls default to 5 visibility checks per type, per player, per tick by default to reduce server lag.

Additionally, this can actually increase client performance on low end devices since entities and block entities are unable to render through walls, reducing unnecessary overhead.

Overview

This anti esp may be the most advanced out of all there have been on fabric, publicly available for use. I would like to disclose the fact that this is the first release, I haven't had much time or the resources to test this extensively. For any bug reports, suggestions or future mod ideas; join my discord server.