Entropie – rules for changing the code

Do's and don'ts that keep the game clean and quick. Short on purpose: add a rule when a mistake shouldn't happen twice, drop one when it no longer holds. Structure: ARCHITECTURE.md.

Do

• Keep the layers: render never includes world, people or game.
• Turn things with the helpers in math/linalg.h (yaw_facing, yaw_along,

yaw_front). Fronts are +Z, lengths are +X.

• Tunables as #define at the top of the file, with unit and meaning.
• Ask "what's near" through the Grid, rays through World_rayCast /

Collider_ray, the ground through World_groundHeight.

• Static things go in before the terrain; things lying on the ground are

placed after it (Scene_finish, Site_finish).

• A new building part: manor.c's Plan (boxes, walls with gaps, openings).
• Rebuild a mesh only when what it shows changes.
• Compile without warnings: -Wall -Wextra -Wpedantic -Wshadow.
• Characters moved by script (stepping over, onto, sitting down) use the set

moves, never a jump of the position. Feet set down by script: the surface plus BODY_ANKLE_Y (scaled), not the ankle's height of the moment.

• A collider's "up" face can be any of its axes (things lie on their side).
• Every version: bump VERSION, update STATE.md (done items out of the to-do

list, version line at the end), keep README.md short (a few lines per area: the details go into STATE.md "Playing it"), write commit_message.txt with this version's changes only.

Don't

• No atan2f for a yaw in new code, no mat4_rotate_y for an object's turn.
• No allocation per frame, no loop over all objects inside a loop over all objects.
• No reusing another kind's fields for a new meaning: add a field, say whose it is.
• No moving static objects behind physics' back (use their own function, then

Object_syncColliders).

• No game rules in render, no input handling in world or people.
• No snapping a character up more than a stair (SNAP_UP_MOST).
• No copying a slab test, ray or spring: there is one of each (Collider_ray,

springStep).

• README: never name Ubuntu (Debian or "any Linux"), always the

"100% Vibecode – but tested" line, no extra files nobody asked for.