Head Trauma Feature

[0xE69]

Head Trauma Feature

Player Impact: Projectile headshots trigger temporary “brain trauma” effects. Severity derives from projectile impact energy after helmet mitigation—ranging from a momentary screen flash to severe nausea, slowness, and aim sway.

Energy Model: Each projectile exposes impactEnergy (damage × speed or KE). Headshots are detected via existing hitbox logic; without helmets, full energy applies. Helmets define absorption, stoppingPower, durabilityPerEnergy, and optional stunThreshold. Absorbed energy reduces helmet durability; the remainder feeds severity selection. Exceeding stopping capacity can still stun and degrade the helmet.

Effect Tiers:

Minor (<20): 10–20 ticks of brief blindness/flicker.
Moderate (20–60): ~5 s nausea/disorientation plus light slowness or dampened turn rate.
Severe (≥60): ~8 s confusion + stronger slowness, sprint suppression, and short aim sway. No-helmet multiplier (e.g., 1.4×) pushes more hits into higher tiers.
Configuration: Forge/JSON config exposes toggles and thresholds (enabled, tier limits, multipliers, sway duration). Helmet entries override absorption/stopping/durability factors for tuning without recompiling.

Implementation Notes:

Apply standard armor damage reduction first, then process trauma using remaining energy.
Client effects: potion statuses for nausea/blindness; custom packets for aim/turn modifiers.
Generate missing helmet assets/entries with sensible defaults; log stun-through events for balancing.
Provide server toggles to disable severe penalties for competitive play and guard client-sent stun state.

[0xE69]

Summary of changes (high level)

• Trauma tiers remain: Minor <20, Moderate 20–60, Severe ≥60.
• noHelmetMultiplier increased to 1.25.
• Helmets and vests get mapped to absorption, stoppingPower, durabilityPerEnergy according to your calibration plan.
• Juggernaut suit is special-cased as the top tier (absorption 0.55, stop 80, durability 0.05) and imposes slower recovery to mirror -15% speed.
• Torso energy is combined from vest base + clothing tier multipliers from ServerConfig (casual/utility/military: 2%/5%/8% damage reduction and 10/20/30% bleed reduction — respected in final torso energy computations).
• Code examples implement these rules and include where to add hooks for client-side aim-sway / recovery penalties.

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Config (JSON) — drop into your mod config file

Expose these so tuning is editable without recompile.

{
  "headTrauma": {
    "enabled": true,
    "minorThreshold": 20.0,
    "moderateThreshold": 60.0,
    "severeThreshold": 120.0,
    "noHelmetMultiplier": 1.25,
    "helmetAbsorptionFactor": 1.0,
    "aimSwayMaxTicks": 60
  },
  "helmets": {
    "defaultAbsorptionBase": 0.30,
    "hardHat": { "absorption": 0.25, "stoppingPower": 25.0, "durabilityPerEnergy": 0.02 },
    "military": { "absorption": 0.35, "stoppingPower": 45.0, "durabilityPerEnergy": 0.035 },
    "juggernaut_helmet": { "absorption": 0.45, "stoppingPower": 65.0, "durabilityPerEnergy": 0.05, "stunThreshold": 80.0 }
  },
  "vests": {
    "weak_tactical": { "absorption": 0.30, "stoppingPower": 40.0, "durabilityPerEnergy": 0.025 },
    "riot_vest": { "absorption": 0.45, "stoppingPower": 65.0, "durabilityPerEnergy": 0.04 },
    "juggernaut_suit": { "absorption": 0.55, "stoppingPower": 80.0, "durabilityPerEnergy": 0.05, "slowRecovery": true }
  },
  "clothingTiers": {
    "casual": { "damageReductionPercent": 0.02, "bleedReductionPercent": 0.10 },
    "utility": { "damageReductionPercent": 0.05, "bleedReductionPercent": 0.20 },
    "military": { "damageReductionPercent": 0.08, "bleedReductionPercent": 0.30 }
  }
}

---

Mapping rules (explicit)

1. Head hit handling

   • incomingEnergy computed from bullet (use your KE formula).
   • If helmet present, get helmet props: absorption, stoppingPower, durabilityPerEnergy, stunThreshold (optional).
   • absorbed = min(incomingEnergy * absorption, stoppingPower)
   • remainingEnergy = incomingEnergy - absorbed
   • Damage to helmet durability: ceil(absorbed * durabilityPerEnergy)
   • If remainingEnergy >= stunThreshold (if present) flag for a "stun-through" severe effect even if helmet absorbed some.
   • If no helmet, multiply incomingEnergy *= noHelmetMultiplier.

2. Torso handling

   • Use vest props first (absorption & stoppingPower from vest item).

   • Then apply clothing tier multipliers from ServerConfig (casual/utility/military) to reduce remaining energy further:

     • Effective torso absorption = vestAbsorption + (1 - vestAbsorption) * clothingDamageReductionPercent

       • (This prevents simple additive overflow; it treats clothing tier as additional fraction of remaining energy).

   • absorbedTorso = min(incomingTorsoEnergy * effectiveTorsoAbsorption, vestStoppingPower)

   • remainingTorsoEnergy = incomingTorsoEnergy - absorbedTorso

   • Durability damage to vest: ceil(absorbedTorso * durabilityPerEnergy)

3. Effects mapping

   • Use remainingEnergy to pick Minor/Moderate/Severe effects as in your trauma system.
   • Juggernaut suit: if equipped apply slower recovery flags (for example, halve aim-sway recovery rate or add a 1.15x duration to trauma effects) to mirror the -15% speed penalty.

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Juggernaut special handling

• Juggernaut suit: absorption = 0.55, stoppingPower = 80, durabilityPerEnergy = 0.05.
• If player has Juggernaut suit: after applying trauma effects, increase effect durations by 15–25% (reflecting slower recovery) and optionally increase aim-sway intensity.
• Also respect existing juggernaut_clothing +5 armor and -15% speed in other systems; link isSlowRecovery() to that item.

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Balancing notes & testing checklist

1. Unit-test values: Log incomingEnergy, absorbed, remaining, durabilityDamage for head & torso hits across:

   • Handgun, SMG, Rifle, High-powered Rifle
   • No helmet, light helmet, military helmet, juggernaut helmet
   • Weak vest, riot vest, juggernaut suit
   • Clothing tiers: casual/utility/military

2. Playtest scenarios:

   • Headshots with & without helmets — verify the bump into Moderate/Severe when unhelmeted with noHelmetMultiplier=1.25.
   • Repeated hits to see durability consumption matches expectations.
   • PvP balance: make sure helmets don't make headshots irrelevant but still meaningful.
   • Zombies biting a player wearing firefighter suit / winter coat; confirm infection chance drops appropriately.

3. Tuning tips:

   • If helmets feel too weak, raise helmet absorption by +0.05 or stoppingPower by +10.
   • If players exploit vest durability (i.e., absorb too much without cost), increase durabilityPerEnergy slightly.
   • Keep severe trauma rare — add a config option to cap frequency on PvP servers.

• Generate concrete Java classes implementing IProtectiveGear for every item you listed (tactical, riot, army, juggernaut, hard-hat, etc.) with the calibrated numbers.
• Produce a single-file drop-in event handler (full class) with these rules and method stubs for detectHeadshot, computeBulletEnergy, and the client packets for aim-sway.
• Produce a test harness (small unit tester) that simulates bullets of different energies and prints logs for absorption/durability helps tuning quickly.

[0xE69]

Goals

• Let existing medical items interact meaningfully with head/torso trauma and bleed/infection mechanics.
• Keep items distinct and valuable: bandages stop/slow bleed, splints fix mobility from bone trauma, morphine/adrenaline reduce disorientation and temporarily boost performance, first-aid kits provide both bleed/infection repair and partial trauma recovery.
• Prevent instant full-heal exploits — add cooldowns, stacking rules, and limits by severity.

High-level mapping (recommended)

• Bandage

  • Primary: stops/reduces bleeding chance and bleed damage.
  • Secondary: small (instant) reduction of minor trauma duration (remove blindness flicker only).

• Splint

  • Primary: fixes broken-limb mobility penalties (not head trauma).
  • Secondary: small reduction to blunt-trauma slow effects on torso.

• First-Aid Kit

  • Primary: removes bleeding, reduces infection chance by X, repairs clothing/vest durability slightly (optional).
  • Secondary: medium reduction to trauma severity/duration (reduces moderate → minor, severe → moderate).

• Morphine Syringe

  • Primary: reduces nausea/aim-sway and shortens potion-effect durations from trauma (fast acting).
  • Secondary: small temporary boost to movement speed/reaction (simulates pain suppression). Has a cooldown per-player (e.g., 120s).

• Adrenaline

  • Primary: temporary removal/strong reduction of aim-sway and movement penalties, minor health regen (or temporary resistance to stun).
  • Secondary: increases heart rate — small increase to bleed chance for short time (tradeoff). Long cooldown (e.g., 180–300s).

Suggested numbers (tunable)

• Bandage: instant stop current bleed; reduces bleeding chance by 50% for 60s; small trauma duration reduction: minus 10 ticks from blindness / remove minor effect.
• Splint: removes "limb broken" flag; reduces bluntResistance effect duration by 25% for 120s.
• First-Aid Kit: heals X health (existing), removes bleed, reduces infection chance by 65% for 300s, reduces current trauma severity by 1 tier (severe→moderate, moderate→minor) and halves remaining effect durations.
• Morphine: on use, reduce current trauma severity by 1 tier (if severity>1), or if severity==1 remove minor effect; reduce aim-sway intensity by 80% and nausea ticks by 50% for morphineDuration = 80 ticks (4s) + morphineAftereffect mild drowsiness (25 ticks). Cooldown: 120s (2400 ticks).
• Adrenaline: on use, reduce aim-sway by 100% and halve slowness for adrenalineDuration = 60 ticks (3s). Apply small bleedChance multiplier +10% for 30s. Cooldown: 300s (6000 ticks).
• Limits: Morphine & Adrenaline cannot be used more than once every cooldown. FirstAid can be used freely but is consumable and rarer.

Config additions (add to trauma_config.json)

{
  "medicalItems": {
    "bandage": {
      "bleedStop": true,
      "bleedChanceReduction": 0.50,
      "durationTicks": 1200,
      "traumaMinorTickReduction": 10
    },
    "splint": {
      "removeBrokenLimb": true,
      "bluntDurationReductionPercent": 0.25,
      "durationTicks": 2400
    },
    "firstAidKit": {
      "healAmount": 8.0,
      "removeBleed": true,
      "infectionChanceReduction": 0.65,
      "traumaSeverityReductionTiers": 1,
      "traumaDurationMultiplier": 0.5
    },
    "morphine": {
      "severityReductionTiers": 1,
      "aimSwayReductionFactor": 0.8,
      "nauseaDurationMultiplier": 0.5,
      "durationTicks": 80,
      "cooldownTicks": 2400
    },
    "adrenaline": {
      "aimSwayReductionFactor": 1.0,
      "slowReductionFactor": 0.5,
      "bleedChanceMultiplier": 1.10,
      "durationTicks": 60,
      "cooldownTicks": 6000
    }
  }
}

Server-side integration (Forge-style snippets)

1. Player cooldown tracker / capability
   Add a small capability or PlayerData map to track medical item cooldowns and active medical-effects (server authoritative).

public class MedicalCooldowns {
    private final Map<UUID, Long> lastMorphineUse = new HashMap<>();
    private final Map<UUID, Long> lastAdrenalineUse = new HashMap<>();

    public boolean canUseMorphine(PlayerEntity p) {
        return !lastMorphineUse.containsKey(p.getUUID()) || (p.level.getGameTime() - lastMorphineUse.get(p.getUUID())) >= ProtectionConfig.GLOBAL_MEDICAL.morphineCooldownTicks;
    }
    public void setMorphineUsed(PlayerEntity p) {
        lastMorphineUse.put(p.getUUID(), p.level.getGameTime());
    }
    public boolean canUseAdrenaline(PlayerEntity p) {
        return !lastAdrenalineUse.containsKey(p.getUUID()) || (p.level.getGameTime() - lastAdrenalineUse.get(p.getUUID())) >= ProtectionConfig.GLOBAL_MEDICAL.adrenalineCooldownTicks;
    }
    public void setAdrenalineUsed(PlayerEntity p) {
        lastAdrenalineUse.put(p.getUUID(), p.level.getGameTime());
    }
}

Hook this into a server-side singleton or attach to player capability for persistence.

TraumaState API (suggested server-side object)

Create a TraumaState per-player that stores:

• severity (0 none, 1 minor, 2 moderate, 3 severe)
• remaining durations for nausea/blindness/slowness/aimSway
• current aimSway intensity
• flags for slowRecovery
• methods used above: lowerSeverityBy(int), clearMinor(), multiplyNauseaDuration(double), applyAimSwayReduction(factor, ticks), multiplyAllDurations(factor), reduceMinorByTicks(int), multiplySlowness(factor, ticks).

This object is authoritative server-side and sends trauma packets to the client whenever it changes.

Client-side changes

• TraumaPacket already exists from earlier plan. Extend it to carry temporary overrides from medical items (e.g., aimSwayIntensity override and duration).
• Client handler should apply incoming medical-augmented trauma params and respect cooldown visuals (e.g., show a small HUD icon for morphine/adrenaline cooldown).
• For adrenaline: if you apply bleed chance increase server-side, client can show a warning icon "Elevated Bleeding Risk".

Balancing & Anti-exploit rules

• Cooldowns: morphine/adrenaline must use cooldown; first-aid no cooldown but is rare and expensive.
• Stacking: medical item effects of the same type do not stack. E.g., using morphine while morphine active refreshes duration but does not double effect; using both morphine and adrenaline applies the stronger immediate benefits but both cooldowns still apply.
• Severity floor: first-aid and morphine can reduce severity by 1 tier each time, but cannot go below 0 or reduce to "no-damage" — severe trauma requires time to fully heal.
• PvP limitations: add server toggles to disable adrenaline/morphine in PvP servers if desired.

Testing checklist

1. Use morphine during moderate head trauma: verify nausea ticks drop, aim-sway reduced, cooldown set.
2. Use adrenaline while severely stunned: verify instant aim recovery, sprint speed restored for duration, bleed chance increased for configured time.
3. Use first-aid kit during severe trauma: severity drops by 1 tier, durations halved, health restored per config.
4. Validate bandage stops bleeding and reduces subsequent bleed chance; confirm splint removes broken-limb movement penalty.
5. Attempt rapid morphine spam: ensure cooldown prevents repeated usage and no stacking.
6. Verify server-client sync: when item used on server, client receives packet and visual/audio cues.

UX notes (recommended)

• Play a distinct "injection" sound and show a small icon + timer for morphine/adrenaline.
• First-aid kit should have a longer animation (so players are exposed while using it) to prevent instant use in combat.
• Bandages should be quick to apply (small animation) so players can triage mid-fight.
• Consider adding log messages in debug builds that report trauma state changes for tuning.