PhysicsConstants.hpp

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#pragma once

namespace physics
{
 
// Gravity & jumping
constexpr float k_gravity = 1000.0f; 
constexpr float k_playerGravity =
    2.0f * k_gravity; 
constexpr float k_jumpSpeed = 660.0f; 
 
// Ground movement
// Ground wish speed is stance-dependent — see tms::k_walkSpeed / k_sprintSpeed / k_crouchSpeed
// and systems::currentWishSpeed() which selects between them.
constexpr float k_groundAccel = 10.0f; 
 
// Air movement
constexpr float k_airAccel =
    700.0f; 
constexpr float k_airMaxSpeed = 30.0f; 
 
// Air wish-speed curve (lets you recover from low/zero air speed without breaking strafe-jump).
// Per-tick gain in wishDir is bounded by wishSpeed when below it, so this also bounds the
// initial "kick" from a stationary air state. Larger k_airMaxWishLowSpeed = stronger recovery
// but feels more teleporty at exactly the moment you start pressing a direction in air.
constexpr float k_airMaxWishLowSpeed = 120.0f; 
constexpr float k_airWishCurveTop = 250.0f;    
constexpr float k_airWishCurveExponent = 0.4f; 
 
// Friction
constexpr float k_friction = 7.5f; 
constexpr float k_stopSpeed = 150.0f; 
 
// Collision
constexpr float k_overbounceWall = 1.001f; 
constexpr float k_overbounceFloor = 1.0f;  
 
// Geometry
constexpr float k_stepHeight = 18.0f; 

constexpr float k_floorAngleCos = 0.7f;

constexpr float k_groundSnapDistance = 8.0f;

constexpr float k_emergencyUnstickRadius = 64.0f;

constexpr int k_maxDepenPasses = 6;
 
// Gravity flip
constexpr float k_gravityFlipCooldown = 0.5f; 
 
// Sub-stepping (Phase C of physics-future-path.md)
//
// The 128 Hz bump loop is conservative-advancement-via-sweep-TOI: each clip
// iteration advances to the swept time-of-impact, never penetrating past
// the swept-shape's safety margin.  This is exact for our plane / brush
// queries and the capsule-vs-triangle Voronoi sweep, and bounded
// conservative for capsule-vs-box/cyl/sphere.
//
// At normal player speeds (≤ 800 u/s, ≤ 6.25 u/tick at 128 Hz) and a 16 u
// capsule radius, one sweep per tick comfortably catches any thin feature.
// The failure mode shows up at extreme velocities (grapple-hook yank,
// explosion knockback, scripted teleports): when `|v|·dt` exceeds the
// shape's safety margin, the sweep's per-tick swept distance can exceed
// the size of thin geometry features, risking tunneling.
//
// Sub-stepping splits the tick into N equal substeps when the projected
// motion exceeds `k_substepSafetyRatio · min_shape_radius`.  Each
// substep runs the full bump loop with `dt/N`.  Determinism is preserved
// because both client and server compute the same `N` from the same
// inputs.  Depen runs once per tick (its idempotence + the bump loop's
// pushback handle the rest); slope-stick and ground-probe also run once
// at the end of the tick.
 
constexpr bool k_enableSubstepping = true;   
constexpr float k_substepSafetyRatio = 0.5f; 
constexpr int k_maxSubsteps = 8;             
 
} // namespace physics