ReSkate/contrib/board-break.md

Board Break

A hard slam can break the local skater's board: at the nose, in the middle or at the tail. Half the time the grip tape holds the pieces together and the board folds or an end hangs; otherwise a piece comes off, flies and lies where it lands, truck and wheels with it. The board is whole again once the skater has picked it up, rides again or respawns. Built into ReSkate; the broken pieces themselves come from a content mod with the deck shapes in it.

Boards also wear: every hard landing, rail hit, grind and slam takes something out of the board of the deck in the game, and a worn board steers lazier, wobbles, breaks from less and in the end can give way under the rider. A boardslide or darkslide that comes down too hard onto a rail can snap the board and throw the rider. A break cracks (and sounds like metal when it happened on metal), and the body's hits in a bail are heard where and as hard as they land. The player sets all of it.

Code: board_break.cpp (client tick, the boards' render pose hook, wear, rail snaps), board_break_model.h (the rules and the geometry on their own) and board_break_feel.h (the settings, what each hit wears, what wear does, rail contacts), both with tests, board_break_audio.cpp (the sounds), board_break_commands.cpp (console), and the deck's place in the mod list in mod_catalog.cpp.

What the player gets

• A slam of force 10 or more always breaks the board, a lighter one a quarter of the time, rising in between (the force is the bail cause's that led to the wipeout). Now and then a board gives way while it is ridden: the nose goes.
• boardbreak 0|1, boardbreak deck [name|number|next], boardbreak snap [nose|mid|tail] to look at a break (that one stays until boardbreak mend or a respawn). The switch and the deck are in the menus beside Road Rash (Mod Options > Player, and the overlay's Skater page). The overlay has a card BOARD BREAK DECK with a button for each deck, on the Mods page and under the switch: a press asks for that deck, the mods are applied and the level loads again with it. The switch is saved with the profile.
• A break plays back in the replay editor as it happened.
• Wear and tear. Each deck's board wears from 0% (new) to 100% (worn out): a landing coming down faster than 3.5 m/s, a hit onto a rail or ledge (harder on a slide than on the trucks), every second of grinding or sliding, and a slam of force 4 or more. The menus call it new, used, worn, beat or done. From a fifth worn the board answers the steering less and its trucks go soft and twist further; worn out, it takes half the force to break and can give way under the rider. A board that broke is a new one once it is whole again; a worn one is renewed with the button New board or boardbreak worn 0. The scratches are the game's own board wear (Mod Options > Board wear), cleared with every new board.
• Rail snaps. A boardslide, lipslide or darkslide that comes down onto a rail or ledge at 3 m/s or more (2.2 on the grip) can snap the board in the middle, certainly 3 m/s above that, and the rider goes down with it. Grinds on the trucks never do.
• Sounds. A crack by the size of the break, a metal one on top when the board broke on metal, and the body's hits in a bail, louder the harder they land.
• Settings, on the overlay's Skater page in a card BOARD BREAK SETTINGS (with how worn the board is): always break (for replay clips), rail snaps, wear and tear, break sounds, body hit sounds, break sensitivity (10% to 400%), how many breaks the grip tape holds (0% to 100%), wear speed (0% to 500%), and New board. Always break and wear and tear are also rows in the game's Mod Options. The console has them all: boardbreak always|sensitivity|joined|rails|wear|wearrate|cracks|bodysounds [value], boardbreak worn [percent], boardbreak status, and for metal boardbreak metal mark|unmark|clear|list and boardbreak materials. They are kept, with each deck's wear and the materials marked as metal, in %LOCALAPPDATA%\ReSkate\BoardBreak.settings.
• Without a deck pack installed nothing breaks and nothing is changed.

How it works

• One deck model. Every board in the game draws the same deck mesh (characters/skateboard/unlicensed/deck/generic/popsicle/2022/deck_gen_popsicle_mesh); deck graphics and grip tapes are items on top of it, and an item cannot bring a mesh of its own. So a breakable deck is a content mod that replaces that mesh: the same deck, plus four stretches of it (nose, front, back, tail) cut along three rows of vertices the deck already has, each rigidly skinned to a bone of the board's rig that the game does not use (Trajectory, Connect, Ground, and Connect2 for the tail, which hangs on Connect).
• Only bones move. board_render_pose (the hook multiplayer already has for other players' boards) runs after a board's pose has been handed to the renderer, which is the one moment a change to the pose is still drawn and not yet rewritten: the board's animation writes every bone again every frame. A broken board gets its Deck bone moved 2 km down, the trucks (which hang on it) moved back by as much, and each stretch moved to where its piece lies. The piece that came off is flown by the hook itself, from the board's place at the break: a kick, gravity, the ground, and written relative to wherever the board is in each frame.
• Nothing is scaled. The first version shrank the deck and scaled the stretches up. The game's replay records where a bone is and how it is turned, and not its size: a shrunk deck played back as a small whole board, and stretches that were scaled up not at all. Moves play back exactly.
• Whole boards hide their stretches too. The deck is a hollow shell (the wood has no top face, the grip is a sheet over it), and the game draws wood and grip as layers that do not hide what lies just under them: stretches left inside a whole deck showed as cracks through the grip, fainter the deeper they lay and never gone (tried down to 4 mm). So every frame, on every board that passes the hook (the local one, other players'), the stretches of a whole board are moved away like a broken board's deck. The call into Board Break is the last thing the hook does, after another player's pose has been written, so that pose's bones do not bring them back.
• Which deck is in the game is a question for the mod list, because any mod that reshapes the deck replaces the same mesh and the one higher in the order has it. When the mods are put together, the Board Break deck the player chose goes first, and what would fight it is set aside for the run: the other Board Break decks, and other mods whose bundle lists name the deck's bundle. Those are left out whole (with the breakable deck in place of its own, a wide-deck mod has its trucks and wheels on a deck they were not made for). mods.json is not changed; the mod list shows them as SET ASIDE.
• Another deck without a restart. The deck mesh is in the items superbundle, which a live apply of the mods already refreshes, and the game reads the mesh when a level loads. Choosing a deck saves the choice, applies the mods and loads the level again (live_mods.h).
• The choice is a line in %LOCALAPPDATA%\ReSkate\BoardBreak.deck, not a profile preference: the mods are put together before the profile is there.
• The sound is a wave file from the sounds folder of an installed deck pack (subfolders light, medium, heavy, by the size of the break), played straight to the speakers.
• The slam's force comes through No Bail's existing hooks: the cause it records for the watched skater, and the cause collector at the moment the selector chooses Wipeout. Nothing new is hooked.
• The trucks' baseplates. The game's truck model (one for every truck item, characters/skateboard/unlicensed/truck/generic/default/2022/truck_gen_default_mesh) has its hangers on the trucks' bones and everything bolted to the deck, the baseplates and their bolts, on the deck's bone. With the deck's bone moved away to hide the real deck, a broken board had hangers and wheels and no baseplates. The decks inside a deck pack bring a copy of the truck model with those vertices on the trucks' effectors instead (eff_truckBack, eff_truckFront: a bone under each truck's that no model uses), and the hook writes each effector from its truck's bone as the animation left it, so that the truck's bone followed by the effector's is what the two are at rest: on a whole board the baseplate sits on the deck however the truck steers, and a truck that a piece carries off takes its baseplate along (baseplate_bone, with a test). That is done on every board that passes the hook. With the game's own truck model nothing is on the effectors and writing them shows nothing.
• On foot the grip tape always holds. A loose piece takes the ground from where the board rolled or lies; a board in the skater's hand does not tell where the ground is, and a piece that came off there hung in the air at hand height.
• Every physics step of the local skater (a step listener of No Bail's) is where wear, rail snaps and the body's hits are seen. How fast the board came down is its root body's speed in its last step in the air; a landing is that step followed by rolling (physics states 1xx), a hit onto a rail by grinding (4xx). What kind of contact it is comes from the board's axes, from the client tick, against how it moves (contact_of): across its way it slides, on its grip it is a darkslide, else it grinds on its trucks.
• What wear does to the handling is four values of the game's own physics tuning (PhysicsSteering.GeneralScalar, PhysicsTrucks.StaticTruckSpringStrength, StaticTruckDamping and TruckTwistLimit), each the game's value times a factor of the wear. A value the player changed (the trainer) is left alone, and nothing is changed in a multiplayer session, whose players share their tuning.
• A rail snap throws the rider through No Bail (no_bail_request_wipeout): the cause goes in just before the game's selector picks the next state, the way the game's own contact tests record theirs, and the pick becomes Wipeout. The force is kept low (2.5): the game reads a cause's force as how hard the rider was hit, and a slam's (10 and more) with the board flat on a rail threw the rider high into the air.
• Metal. Each contact effect the game plays (sparks, dust, landings) names a material of the level (Extension/Multiplayer/Remote/native_vfx.h, recent_local_impacts); Board Break installs that hook once in a world, as multiplayer would. The level's materials have no names that can be read, so which are metal is a list: marked in play with boardbreak metal mark while grinding a metal rail, and brought by a pack in sounds/metal/materials.txt.
• The body's hits are the ragdoll's contacts that Hall of Meat reads each step, one sound at a time, none below a graze.
• The sounds play through XAudio2 on a thread of their own, several at once and each at its own loudness; 16-bit and 32-bit float wave files both play.
• Wider decks, wider trucks. The game puts each wheel on its truck's bone along the axle, about 0.0876 m out. A deck that says so (deck.ini axle) has its wheels set further apart, or closer, by the render pose hook: set, not scaled, so a pose that comes by twice is not moved twice, and only what is drawn changes. The deck's own truck model is made to match.
• Off, the board holds. Without a deck pack in the game the hook returns at once.

The deck packs

A deck is a content mod's copy of the deck model (no code), and comes in one of two ways:

• a mod folder named Board_Break_<Name> holds the deck <name>;
• a deck pack, a mod folder of any name, holds a deck in each decks/<name>/, laid out like a mod folder (layout.toc, Win32/...). The launcher installs one mod folder per package, so this is how one package brings every deck. When the mods are put together each deck inside becomes a mod of its own for the run, listed as <folder>#<name>: it is chosen, set aside and switched like a deck in a folder of its own (its archives are placed like a disabled mod's). mods.json and the mod list only know the pack, which counts as loaded when one of its decks is. The launcher takes a folder for a mod only when it has a layout.toc of its own. That layout is not one of the pack's decks, whatever the folder is named, and is set aside like any other deck model; it is what an older ReSkate loads from the pack. ReSkate 2.0.6 knows a deck by its folder's name only, so a pack in a folder named Board_Break_<Name> (the package Board_Break_Pack, installed as Team-Board_Break_Pack) with a breakable deck as its own layout breaks boards there with that one deck, and brings all its decks from this version on. The truck model with the baseplates on the effectors belongs in the decks inside the pack only: a ReSkate that does not place those bones would draw the baseplates turning with the hangers, and such a version reads the pack's own layout, never decks/.

The name is what the deck goes by. The ten the feature was made with are standard, wide, concave, powell, slim, egg, square, shaped, oldschool and pig, and the console also knows those by number. Any other deck that follows the recipe works, with no change to ReSkate:

• Start from the deck mesh as ReSkate Studio exports it (three parts on the bone Deck: the grip sheet, the wood, and a plain copy of the whole deck). Studio only takes back a mesh whose triangles are the donor's own, so a shape is made by moving vertices, never by adding any. Keep every vertex where it is along the board: the break rows (z = 0.260, 0.009 and -0.260 m) and the truck bolts stay put.
• For each of the four stretches, append a copy of every part's vertices and triangles, skinned to that stretch's bone, with every vertex on the far side of its break rows folded onto the row's cross-section (top skin onto its top line, bottom skin onto its bottom line). That leaves the deck's own edge faces standing in the gap as the broken end. Push the row itself along the board by a jagged line, the same line for both sides of a break, so the pieces fit together.
• Build the stretches at their own size, in the place they have in the whole deck.
• The truck model for a deck inside a pack: the game's own, with every vertex that is on the bone Deck moved to eff_truckBack (behind the middle of the board) or eff_truckFront (ahead of it). Nothing else changes; Studio takes it back as it is.
• The sounds are sounds/light|medium|heavy|metal|body/*.wav in the folder of any mod that brings a deck (a crack size without sounds of its own takes the nearest that has some), and sounds/metal/materials.txt may list the level's materials that are metal, by number.
• A deck may say something of itself in a deck.ini in its folder (a pack's decks/<name>/, or the Board_Break_<Name> folder): label = Old School, its name in the menus, and axle = 1.17, how far apart its wheels sit against a standard board's (0.8 to 1.6), for a deck wider or narrower than the standard one.

Seen working in game

Offline, on main at f4292d6, with eight decks installed, each in a folder of its own and all of them in one deck pack: breaks from real slams at the nose, in the middle and at the tail, clean and held by the grip, the board whole again in hand and on respawn; breaks from the console on foot (folded, nose and tail hanging) that stay until mended. The grip side of a whole board, close up in the board menu, shows no cracks. A deck chosen while the game runs is the one in the board menu and in the world after the level has loaded again (about 20 s), and the one the next launch starts with. With a wide-deck mod switched on and first in the order, the breakable deck is still the one in the game and the mod is set aside; so is an older deck mod of Board Break's own. The mod list shows the decks that are set aside as such, with nothing waiting to be applied. With a pack first in the order (on main at 1b15a04, 2.0.6), the deck the game starts with and the deck chosen while it runs both come from inside the pack, the deck list has the pack's eight decks and no more, and the pack's own layout is set aside: tried with the game's own deck there, and with a breakable deck there in a folder named FourthStudio-Board_Break_Pack. That last pack on 2.0.6 as released: its own layout is the deck "pack", loads first and breaks at the nose, in the middle and at the tail. The switch on the overlay's Skater page turns it off and on. On the older build the feature was developed on, a middle break played back in the replay editor.

On main at 8351654, with the pack as the only source of decks (its decks with the truck model that has the baseplates on the effectors): a dozen breaks from real slams at the nose, in the middle and at the tail, clean and held by the grip, with the baseplates on the pieces, and on the whole board in hand and on the ground. The effectors are bones 5 and 9 of the pose, each at 0.0395 m along its truck's bone and not turned, as the rig has them. A press on Shaped in the overlay's deck card: the mods applied in 3.8 s, the level loaded again in 15 s with that deck, which then broke. In the game's Mod Options > Player page, on 2.0.6: one press on Board Break deck is one deck further and one reload.

Wear, rail snaps, sounds and settings, in the player's own game offline, on the first build of them (on main at 6c45e96): boardslides that came down onto rails at 4.6 to 7.0 m/s snapped the board in the middle; the settings card switched always break on; boards wore, at that time far too fast (the rates are a third of that now).

Not tried yet

• Multiplayer: other players' boards are only handled by the code path (their stretches are moved away), not seen; what peers see of a broken board, with and without the packs.
• The online route: all of the above ran on the offline profile.
• The replay editor on this branch (the replay was checked on the older build the feature was developed on).
• The deck card with a deck that is not one of the eight, and with none installed (it draws nothing then).
• A board that does not pass the render pose hook, with the truck model from a pack: its baseplates would follow the hangers.
• A mod that brings a truck model of its own beside a deck pack: the pack's is the one that loads.
• A level change in the middle of a break.
• The rider going down with a board that snapped on a rail, and the material a board broke on: both changed after the build that was played. No material is marked as metal yet, so the metal sound waits for boardbreak metal mark or a pack's list.
• The body's hit sounds in a real bail.
• Wear's effect on the handling, felt in play, and a worn-out board giving way.
• The Old School and Pig decks, and wheels set further apart by axle, in play.
• This branch as it is, on main at 6df4f9a: built without warnings and its tests run, not played.