Bring realistic diving, oxygen, atmospheric pressure and environmental physics to Minecraft 1.12.2!
Diving & Oxygen transforms underwater exploration and high-altitude environments with dynamic systems for pressure, oxygen, decompression, wind and water physics.
Every depth, altitude, biome and weather condition can influence the environment around you, making exploration more immersive, technical and dangerous.
Pressure naturally increases as you dive deeper
Pressure is calculated from the actual depth of the water
Pressure is displayed in atmospheres (atm)
Atmospheric pressure also changes depending on your altitude above sea level
Above 2.2 atm, increased pressure begins causing physiological effects
Extreme pressure can cause Slowness, Nitrogen Narcosis, Muscle Fatigue and direct damage
The pressure system continuously updates based on your current environment
Diving & Oxygen replaces the vanilla air bubble system with a dedicated oxygen reserve.
Oxygen consumption dynamically changes depending on your activity:
Resting: 1× base consumption
Moving: 1.3×
Sprinting: 1.8×
Active swimming: 2×
High pressure: +15% consumption per additional atmosphere
At the surface, oxygen gradually regenerates after a short configurable delay.
At high altitude, the thinner atmosphere reduces oxygen recovery and can eventually prevent oxygen from regenerating without proper equipment.
Your body gradually absorbs pressure while diving.
A simplified tissue decompression model continuously compares tissue pressure with the surrounding ambient pressure.
Ascending too quickly can cause increasing levels of decompression stress:
Stage 1 — Stress > 1.0: Muscle fatigue
Stage 2 — Stress > 2.5: Slowness and nausea
Stage 3 — Stress > 4.5: Blindness and recurring internal damage
The deeper you dive and the faster you ascend, the greater the potential decompression stress.
Ascend carefully after deep dives to reduce the risk of decompression effects.
Pressure doesn't only change underwater.
As you climb higher, atmospheric pressure gradually decreases:
Below 0.75 atm: Slowness
Below 0.55 atm: Fatigue and Weakness; oxygen can no longer regenerate without equipment
Below 0.40 atm: Direct hypoxia damage
Altitude also affects the recovery rate of your oxygen reserve.
Diving & Oxygen adds dynamic environmental forces that affect players and living entities.
Wind is calculated in 3D using multiple environmental factors:
Altitude — wind becomes stronger at higher elevations
Terrain exposure — 12 3D detection rays analyze surrounding blocks
Shelter — nearby solid blocks reduce wind exposure
Weather — rain and thunderstorms can increase wind intensity
Random gusts — wind strength and duration vary dynamically
Elytra — flying with an Elytra gives the player maximum wind exposure
Wind applies a vector force to entities, with the resulting acceleration being affected by their mass.
Water movement changes depending on the environment.
Oceans
Semi-stable current cells
Slowly changing rotational patterns
Dynamic underwater movement
Rivers
Current direction is based on the terrain slope
Terrain is detected in four directions to determine the flow
Surface Waves
Uses a double harmonic sinusoidal system
Combines a main frequency with a modulation frequency
Causes players at the surface to gently oscillate vertically
At the surface, players can slowly drift and move with the waves, creating a more dynamic water environment.
Environmental forces also affect living entities.
All EntityLivingBase entities can be affected by wind and water currents depending on their mass.
The basic physics model is:
acceleration = force / mass
Minecraft vanilla mobs have predefined masses.
For mobs from unknown mods, their mass can automatically be estimated from their hitbox volume:
width × height × width
This allows the environmental physics system to interact with mobs from other mods without requiring predefined values.
/mobmass CommandAn administrator command allows you to manage mob masses individually for each world.
| Command | Description |
|---|---|
/mobmass set <id> <mass|immune> |
Sets the mass of a mob type |
/mobmass get <id> |
Displays the current mass |
/mobmass reset <id> |
Removes the custom mass override |
/mobmass list |
Lists all custom mass overrides |
Using immune or 0 makes a mob immune to environmental forces.
Mass overrides are stored per world using WorldSavedData (NBT).
A dedicated HUD replaces the vanilla air indicators and provides real-time information about your environment and physical condition.
The HUD displays:
Ambient pressure in atm
Environment type: SURFACE / DIVING / ALTITUDE
Dive time
Decompression stress
Oxygen reserve
Ascent rate, smoothed to prevent sudden value changes
Wind and current direction
Environmental warnings when conditions become dangerous
The oxygen gauge dynamically changes appearance as your oxygen level decreases, making low oxygen levels more noticeable when you are in danger.
The vanilla air bubbles are removed to prevent conflicts with the new oxygen system.
The HUD system has been refactored using DataUI, which provides the UI and rendering framework for the new HUD.
Press F9 to display detailed environmental and physics information in real time:
Player position and biome
Wind vector
Wind speed in km/h
Wind exposure
Gust status
Water current
Water depth
Current direction
Applied forces: Fx, Fy, Fz
Player mass
Weather conditions
Shelter status
Elytra flight status
Extreme environmental conditions can affect your screen.
Hypoxia Vignette
Pulsing dark vignette around the edges of the screen
Activates when oxygen falls below 30%
Decompression Vignette
Pulsing crimson effect around the edges of the screen
Activates when decompression stress becomes high
Both effects can be enabled or disabled through the configuration.
The configuration file:
config/divingoxygen.cfg
allows you to customize many aspects of the simulation:
Water pressure coefficient
Atmospheric pressure coefficient
Sea level
Tissue absorption rate
Critical decompression gradient
Pressure damage
Oxygen consumption rate
Oxygen recovery rate
Altitude hypoxia
Screen visual effects
Diving & Oxygen supports Swimming & Crawling 1.5.2+.
The two mods can work together to provide a complete swimming and diving system:
Detects the Swimming & Crawling swimming pose
Active swimming increases oxygen consumption
Diving depth is dynamically calculated while swimming
Pressure and oxygen systems react to player movement
Swimming activity is taken into account by the oxygen system
Java reflection is used to detect the swimming posture
A vanilla fallback system is included when Swimming & Crawling is not installed
Minecraft 1.12.2
Minecraft Forge 14.23.x
DataUI — required for the new HUD system
Swimming & Crawling 1.5.2+ — optional integration
Compatible with living entities from other mods
Custom mob masses can be configured per world
Environmental forces are handled server-side to reduce synchronization issues in multiplayer
Do I need Swimming & Crawling?
No. The mod includes a vanilla fallback, but Swimming & Crawling 1.5.2+ provides additional swimming posture detection and integration.
Do I need DataUI?
Yes. DataUI is required for the new HUD system and provides the UI and rendering framework used by the Dive Computer HUD.
Does the mod replace the vanilla air bubbles?
Yes. Diving & Oxygen uses its own oxygen reserve system instead of the vanilla air bubble system.
Does pressure depend only on diving depth?
No. Pressure is affected by both water depth and altitude above sea level.
Does it work in multiplayer?
Yes. Environmental forces are calculated server-side to help keep the simulation synchronized between players.
Does the mod affect mobs?
Yes. Living entities can be affected by wind and water currents according to their mass. Custom masses can also be configured using /mobmass.
Is this a realistic medical simulation?
No. The pressure, oxygen and decompression systems are simplified gameplay models inspired by real diving physiology.
Does the mod add keybinds?
No. The main systems work automatically based on your environment and player activity.
Developed by Agnist_greg
