Overview

FFMobSunBurnAngle

Uses the sun angle for burning and spawn checks on sunlight sensitive mobs.

Morning scene with the sun low in the sky: one zombie standing in the long shadow of a cliff is not burning, while another zombie a few blocks away in direct sunlight is on fire.

Features

Checks direction to the sun instead of only vertical sky access.
Configurable mob filters, transparent blocks, and performance controls.

FFUtilities is included in this mod JAR (0.2.15 on 26.x, 0.2.8 on 1.21.1); no separate library download is needed.

How it works in detail

Directional sun burning: a raycast toward the sun replaces the vertical sky check.
Day-length friendly: it follows the dimension's celestial angle, so mods that change day length keep working.
Spawn prevention: monsters can't spawn where they have a clear line to the sun.
Transparent blocks: optionally let sunlight pass through glass and other non-occluding blocks. Leaves and mangrove roots still cast shade by default.
Mob filter: all, whitelist or blacklist mode for both burning and spawn checks.
Performance: staggered checks, a shared sun-vector cache and a per-mob decision cache.
Debug rays: optional in-world lines showing what each mob is checking (green means it would burn, red means it is shaded).

Open the config screen from the Mods list (Mod Menu on Fabric; optional).

Configuration

General

Key	Default	Description
`enabled`	true	Master toggle
`checkIntervalTicks`	5	How often each mob re-checks (staggered by entity ID)
`burnRaycastDistance`	64	Max burn ray length
`useCachedSunVector`	true	Cache the sun direction once per world tick
`raycastThroughTransparent`	true	Rays pass through glass and non-occluding blocks
`transparentBlocksTreatedAsOpaque`	leaves and mangrove roots	Blocks that still block the sun when transparent pass-through is on

Mob filter

Key	Default	Description
`filterMode`	`all`	`all`, `whitelist` or `blacklist`
`whitelist`	common undead IDs	Used when the mode is whitelist
`blacklist`	empty	Used when the mode is blacklist

all: every mob that hits the burn and spawn checks
whitelist: only the listed entity type IDs
blacklist: every mob except the listed IDs

Mobs outside the filter keep vanilla sun-burn and spawn behavior.

Spawning

Key	Default	Description
`preventSpawnInSunlight`	true	Block filtered monster spawns that can see the sun
`spawnRaycastDistance`	32	Max spawn-check ray length

Debug

Key	Default	Description
`debugLogging`	false	Verbose logs
`showRaycasts`	false	Draw rays in the world

Good to know

Phantoms: burning is covered, but spawn prevention only applies to monsters that use the standard monster spawn rules (phantoms use their own).
Helmet protection stays vanilla, and no "seek shade" AI is added.
Only undead that aren't fire-immune are checked for burning, so cows and friends never raycast.
Low sun angles still give a valid direction, so burning stays consistent around sunrise and sunset.
Burning re-applies with the vanilla random chance every tick, so burn time and damage match vanilla while a mob stays in sunlight.
There is no datapack support. Choose affected mobs with the mob filter config; vanilla tags and data keep working as usual.

Requirements and source version

Minecraft	Loader	Requires
1.21.1	Fabric	Fabric Loader 0.16.1 or newer and Fabric API
1.21.1	NeoForge	NeoForge 21.1.211 or newer
26.1	Fabric	Fabric Loader 0.18.4 or newer, Fabric API and Java 25
26.1.1	Fabric	Fabric Loader 0.18.5 or newer, Fabric API and Java 25
26.1.2	Fabric	Fabric Loader 0.19.2 or newer, Fabric API and Java 25
26.1.2	NeoForge	NeoForge 26.1.2.114 or newer and Java 25
26.2	Fabric	Fabric Loader 0.19.3 or newer, Fabric API and Java 25
26.2	NeoForge	NeoForge 26.2.0.88 or newer and Java 25
26.3	Fabric	Fabric Loader 0.19.5 or newer, Fabric API and Java 25

Source version: 1.3.0. FFUtilities 0.2.15 is included in the 26.x jars and 0.2.8 in the others.

The Modrinth button is enabled only when a published project link is configured. The source version above may be newer than the latest published file.