Constraints

Engine & Game Limits

The hard numbers the current build enforces. Most are compiled-in defaults; where a level or a def can override one, the row says so. Everything here is checked against the source or the level format, not remembered.

Rule of thumb for authoring: any limit marked silent fails without an error, so a level can look correct and still be unplayable. Those are the ones make test / worldcheck guards.

Player and movement

Limit	Value	Where	Notes
Body height	2.8	PlayerMovement::Height	anchored at the feet
Jump rise	2.25	jump^2 / (2 * gravity) at the 9/18 defaults
Clearance needed to jump	5.05	2.8 + 2.25	a gap below this is a trap: you can stand, not jump
Step height	1.0	kStepHeight	author 0.9; 1.0 sits on a float boundary
Doorway opening	5.5	shipped convention	a lintel below 5.05 jams a jump in the doorway
Storey height	8.0 floor-to-ceiling	shipped convention	7.55 usable over a 0.45 slab; tallest standable prop is 2.5
Gravity	18	PhysicsInfo default	per-zone gravity=
Jump impulse	9	PhysicsInfo default	per-zone jump=
Terminal velocity	60	PhysicsInfo default	per-zone terminal=
Water gravity / drag / swim-up	8 / 0.95 / 5	PhysicsInfo defaults	per-zone water_gravity=, water_drag=, swim_up=
Ladder speed	6	PhysicsInfo default	per-zone ladder_speed=
Fly / noclip multiplier	1.5	PhysicsInfo default	per-zone fly_mult=
Fall damage	none	by design	a long drop is survivable

worldcheck --headroom-all audits the 5.05 rule over every floor plane and reports WARNINGS, not errors, because the shipped worlds carry pre-existing instances.

Collision and level geometry

Limit	Value	Notes
Collision shape	AABB only	rotation is handled by a conservative rotated AABB, which over-covers corners but never under-covers
Heightmap lateral collision	none	a heightmap supplies a surface (ground clamp) only; a steep heightmap cliff is walk-through
CSG carve budget	4096 splits per brush	measured against the growth one brush causes, not the world total; overflow_count() is surfaced as a warning
AutoConvex budget	2048 boxes per action	the build aborts rather than returning a partial hull
AutoConvex cell size	max(0.25, extent / 16)	editor default
sub / intersect	modifiers, not shapes	they carve solids that already exist; a world containing only a sub has no collision at all (silent)

Rendering

Limit	Value	Notes
raylib	5.5	system-wide on Linux/macOS; vendored build on Windows
Light slots	32 per program	MAX_LIGHTS in rlights.h, LitFog.fs and Surface.fs; a test fails if the three disagree
Transient lights	8 reserved	submitted first and never evicted; a level authored to 32 loses 8 the moment a weapon fires
Design budget	24 authored lights	32 − 8
Spot cone	cosines, not degrees	inner_cone / outer_cone
Fog density	exponential rate per world unit	not a linear multiplier; shipped values are 0.0022 – 0.007
Skybox	6 quads at 700 units, V from world elevation	capped at 55° elevation by the wall quads
Per-face surfaces	up to 6 draw calls per brush	only when NeedsPerFaceDraw() is true
Shadows / lens flare	none	castShadow and the flare are stored but have no implementation; see Wiki/Lighting-Plan.md
God rays, PBR, refraction	none	water is a scrolling translucent sheet

Game rules and networking

Limit	Value	Where
Protocol version	2 (enforced)	net::PROTOCOL_VERSION — a mismatched CLIENT_AUTH is dropped
Wire player cap	32	net::MAX_PLAYERS
Advertised slots	levelinfo maxPlayers (shipped 8)	the browser shows the level's number, not 32
Hotbar	8 slots	HOTBAR_SIZE, mirrored by slot < 8 on the server
Zone types	6 — water, ladder, sky, reverb, gameplay-sound, portal	ZoneType
Objective ids	bounded by net::kObjectiveIdMax (ObjectiveStateData::id width)	a longer id is warned once at seed time and would truncate on the wire
Master listing expiry	90 s	heartbeats are 30 s with jitter
LAN discovery	UDP 27100	optional ;http=;map=;pw= tail
Save formats	TF.sav, POS.sav (x:y:z:level:world:), Script.sav, Campaign.sav v1 (v0 still loads)	an unknown version is rejected → fresh start
Player profiles	System/PlayerProfiles.ini, one [Profiles] section
Auth payload	v2, structSize-guarded; every field client-claimed and sanitised	shorter payload = v1 peer, still accepted

Matches run a fixed 20 Hz simulation tick with interpolated movement sub-steps; dt is clamped so a stalled frame cannot tunnel the player through collision.

Content and authoring constraints

Constraint	Why
No folder name may contain a space or a parenthesis	the .ozls stats parser reads one whitespace-delimited token and OZONE has no quote parsing
No quote parsing in OZONE	texPath="my tex.png" splits at the space; only whole-token fields tolerate quotes
A .ozls stat value is one token	slot_rects, sound paths and vec3s must be written without spaces (quotes are only stripped by some consumers)
zone needs an explicit, unique name=	auto-generated names are per-load counters and collide across worlds (silent)
A zone's name= must match its .ozls entity name	the registry drops a def owned by another world, logging only at DEBUG (silent)
Only playerstart #1 is used	#2 onwards is ignored by the client
A once trigger containing the spawn burns its fire on step 1	TriggerSystem treats "inside on the first sample" as an enter
panU=/panV=/surfGlow= need their flag bit	the shader gates the uniform on the flag (silent)
flags= replaces the whole set	OR the bits; never overwrite a brush that carries flags=8
pln is a fixed 10×10 quad	use it as a patch, and give it NO_BSP_CUTS or it becomes invisible collision
cyl / pyr cz is the TOP	box is centre-based; the two conventions differ
UPnP / port forwarding is not automatic	the server announces --public-ip; the host must forward both ports

Where to change them

• Movement and physics defaults: Source/Physics/PhysicsInfo.hpp (per-zone overrides live in Source/World/ZoneTypes.hpp).
• Light budget: Source/Renderer/rlights/rlights.h, GameData/Shaders/LitFog.fs, GameData/Shaders/Surface.fs — all three together; tests/Surface.test.cpp enforces parity.
• Protocol and wire limits: Source/Network/Network.hpp.
• CSG and AutoConvex budgets: Source/Physics/OzBsp.hpp, Source/Physics/AutoConvex.hpp.
• Player slots per level: the world's levelinfo line.