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| 1 | # val |
| 2 | |
| 3 | Five attackers with the spike, five defenders, abilities on cooldown. First to 13. |
| 4 | |
| 5 | A 5v5 played in a browser, from inside the player's head — the map is a tile |
| 6 | grid and the view is a raycaster over it, so there is no 3D library and no |
| 7 | dependency at all. One match is always running on the server: open the page |
| 8 | and you are given a seat in the round that is happening, taken from a bot |
| 9 | where it stands. When a match ends it shows the result for a few seconds and |
| 10 | starts a new one, so nobody ever arrives at a frozen board. |
| 11 | |
| 12 | ## What is real |
| 13 | |
| 14 | Everything that decides a round is computed on the server and only the |
| 15 | server: |
| 16 | |
| 17 | - **Movement, shooting and hit detection.** The client sends intent — a |
| 18 | direction, an angle, a held key — never a position. Damage is by hit |
| 19 | location (how close the ray passes the target) with falloff and armour: |
| 20 | a Vandal head shot kills through full armour at any range, a Phantom's |
| 21 | does not past fifteen metres. |
| 22 | - **Line of sight.** A snapshot only carries the enemies that viewer can |
| 23 | see. A wall of the map blocks the sight line, a smoke blocks it, a flash |
| 24 | blinds by the angle you were facing, and a blinded player is sent no |
| 25 | enemies at all. A dead player watches through their living team mates' |
| 26 | eyes rather than through walls, so dying is not a wallhack to call out. |
| 27 | No spawn can see the other spawn: mid is staggered on purpose. A patched |
| 28 | client learns nothing a plain one does not. |
| 29 | - **The spike.** 100s round, 4s plant, 45s fuse, 7s defuse with a |
| 30 | checkpoint at 3.5s — a defender killed past half way leaves the defuse |
| 31 | half done for the next one. |
| 32 | - **Credits.** 800 to start, 9,000 cap, +200 a kill, +300 to the team on a |
| 33 | plant, loss bonus 1,900 / 2,400 / 2,900. A buy you cannot afford is |
| 34 | refused server-side. |
| 35 | - **Who is alive.** The roster under the view lists your five with their |
| 36 | health from the snapshot's own team data, and the kill feed is derived in |
| 37 | `src/arena.ts` by comparing the players either side of a tick — it carries |
| 38 | names, the gun and an age, and never a position. |
| 39 | - **Bots** fill every empty seat and use their kit: smokes on the way in, |
| 40 | flashes before the entry, a recon dart, a molly on the planted spike. They |
| 41 | shoot through the same spread everyone does, and they aim like something |
| 42 | with hands: 200–350ms to react to a target they have just seen, an aim |
| 43 | cone that opens several degrees on the swing and only settles while they |
| 44 | hold the same target, and more of both when you are crossing their view |
| 45 | (`src/aim.ts`). Every roll of it comes from the match's seeded random, so |
| 46 | a seed replays the same round. |
| 47 | |
| 48 | Agents: Ember, Veil, Sable, Mender, Rook — two basics bought with credits |
| 49 | (charges last the round), a free signature on a cooldown, and an ultimate |
| 50 | paid for with ult points from kills, plants and the two orbs on the map. |
| 51 | |
| 52 | Guns: Classic, Ghost, Sheriff, Spectre, Phantom, Vandal, Operator. |
| 53 | |
| 54 | ## What is not |
| 55 | |
| 56 | - Your own body is *drawn* from a guess — the browser runs your own movement |
| 57 | forward from your own keys between snapshots, through the same |
| 58 | step-and-slide the server uses (`src/glide.ts`), and carries the last |
| 59 | snapshot forward by up to a quarter second of held input. It is a drawing |
| 60 | optimisation only: nothing is sent, every snapshot leans the drawn body |
| 61 | back onto the server's answer, and a real disagreement is taken outright. |
| 62 | The lag your own keys take to reach the server (a send every 50ms, a hop, |
| 63 | a tick — `LEAD_SLACK` in `static/predict.js`) is not a disagreement: the |
| 64 | drawn body may lead the answer by that much along the way it is going and |
| 65 | is left alone there, so a start is not yanked back and a stop is not |
| 66 | dragged on. Anywhere the server would refuse — a wall, the spawn pen in |
| 67 | the buy phase, a barrier an ability put up — the drawing holds its last |
| 68 | good place rather than snapping to the server's. The gun kicks the moment |
| 69 | the trigger is pulled, and the server's word about the same shot is not a |
| 70 | second kick; whether it landed is still only the server's to say. |
| 71 | Where you are *looking* is the browser's too: the mouse moves it at frame |
| 72 | rate, and the server's angle is taken back only when it is telling you |
| 73 | something you did not say (`static/yaw.js`). |
| 74 | - Everybody else is drawn by entity interpolation (`static/interp.js`): each |
| 75 | body keeps the last few snapshots, and the frame is drawn about one |
| 76 | snapshot interval in the past, between the two that bracket that moment. |
| 77 | So they move at the speed the server moved them and arrive where it put |
| 78 | them, one interval late. A missed snapshot is carried one interval further |
| 79 | and then held. Snapshots are filed under an even clock — one interval |
| 80 | after the last, nudged a tenth of the way toward when each really landed — |
| 81 | rather than the moment they happened to arrive, because a rate is not a |
| 82 | rhythm: thirty a second delivered a few milliseconds early and late is a |
| 83 | body drawn slow, then fast. The moment being drawn advances at real time |
| 84 | and creeps toward its delay at no more than two percent of it, so the |
| 85 | delay adapting never shows as a short frame. Snapshots go out every tick |
| 86 | (30Hz, some 3.4 KiB a seat) while two or fewer seats are filled, and every |
| 87 | other tick above that. |
| 88 | - The view is a raycaster: walls are one tile tall and flat-shaded, there is |
| 89 | no looking up or down, and everything that is not a wall — bodies, the |
| 90 | spike, ability zones — is a flat billboard scaled by distance and clipped |
| 91 | against the walls. It is drawn into an offscreen canvas 960 columns wide |
| 92 | (`static/resolution.js`, never more than the canvas has pixels), one ray |
| 93 | every other column, and scaled onto the visible one, so the frame costs the |
| 94 | same on a retina screen as on any other; the crosshair, the HUD and the |
| 95 | minimap are drawn on top at full device resolution. Columns that would draw |
| 96 | the same rectangle are batched into one fill (`static/slices.js`), the |
| 97 | map's tiles are drawn once a size and blitted after that, and if the frame |
| 98 | still runs over 20ms the render width drops a rung until it fits |
| 99 | (`static/budget.js`). Fidelity is cheap here and frame rate is not. |
| 100 | All of it is presentation: the simulation and the snapshots are untouched. |
| 101 | - A body you have only just been shown is faded and grown into sight over a |
| 102 | tenth of a second, and slid in from the direction it came if it was seen |
| 103 | near there before; where somebody was last seen alive leaves an outline |
| 104 | that dims away over a second (`static/presence.js`). The server still sends |
| 105 | only what you can see — that is the rule, and nothing here bends it. This |
| 106 | is a drawing about information you already had: an enemy who steps into a |
| 107 | sightline has no history, and without it they appear mid-stride rather than |
| 108 | walking into the room. |
| 109 | - One map, one match at a time, ten seats. There is no matchmaking, no |
| 110 | ranking and no account: your seat belongs to a session cookie, and a |
| 111 | playing seat is capped one per client address so a cookie — free to mint |
| 112 | again — cannot buy a second one on the other team. A second machine on a |
| 113 | second network is still a second person as far as the server can tell, |
| 114 | the same as any anonymous game without accounts; a socket that does not |
| 115 | get a seat is sent a spectator view with no position in it, never a side: |
| 116 | the page draws the score, the round, the clock and the kill feed, says |
| 117 | which of the two reasons it is watching for, and draws no map and no |
| 118 | bodies, because it is never told where anybody is. |
| 119 | - No overtime — first to 13 ends it at 12–12 too. |
| 120 | - Sight is a full circle rather than a view cone — you are drawn what is in |
| 121 | front of you, but the server reveals anything you have line of sight to, |
| 122 | so a team mate behind you still appears on the minimap. The world has no |
| 123 | vertical, so the hit location comes from how precisely the shot passes |
| 124 | the target. |
| 125 | - Assists are counted as a field but never awarded. |
| 126 | - The live match lives in memory and is gone if the process restarts; only |
| 127 | finished match results are written to SQLite under `FORGE_APP_DATA`. |
| 128 | |
| 129 | ## Playing |
| 130 | |
| 131 | Click the view to capture the mouse, then WASD move and the mouse looks; |
| 132 | **Esc** gives the pointer back. Click fires, **R** reloads, **F** plants and |
| 133 | defuses (hold it), **C / Q / E / X** cast, **B** opens the buy, **Tab** |
| 134 | holds the big map open, **V** swaps to the top-down view, **H** or **?** |
| 135 | brings back the how-to-play card, and **F3** or **`** prints the frame |
| 136 | readout: frame rate, mean frame, snapshots a second, the interpolation delay |
| 137 | in force, the width the world is being drawn at, and how many times the |
| 138 | drawing has taken the server's word outright (your body anchored, somebody |
| 139 | else started again, the view re-pointed) — every one of those is a jump, and |
| 140 | the number a minute is what "it stutters" should be argued with. On a phone |
| 141 | it stays top-down: the left thumb walks and the right thumb aims and fires. |
| 142 | |
| 143 | sh |
| 144 | PORT=8080 FORGE_APP_DATA=./data bun run src/server.ts # run it here |
| 145 | bun test # the check every pull runs |
| 146 | VAL_URL=http://127.0.0.1:8080 bun run src/tty.ts # the terminal interface |
| 147 | |
| 148 | |
| 149 | The terminal plays the same match over the same socket: it draws the grid, |
| 150 | the scoreboard and the round, and takes a seat. The exact command that |
| 151 | reaches it is in `FORGE_APP_SSH` when the app runs, and the page prints it. |
| 152 | |
| 153 | The forge sets `PORT`, `FORGE_APP_DATA`, `FORGE_APP_ENV`, `FORGE_APP_URL`, |
| 154 | `FORGE_APP_SSH` and `FORGE_APP_COMMIT` when it starts the app; `forge.json` |
| 155 | says how. |
| 156 | |
| 157 | ## Shape |
| 158 | |
| 159 | `src/map.ts` the grid and its geometry · `src/weapons.ts` the damage table · |
| 160 | `src/economy.ts` credits · `src/abilities.ts` the agent kits · |
| 161 | `src/match.ts` the round loop (`tick(state, dt)` is the whole game and takes |
| 162 | no clock) · `src/bots.ts` the seats nobody is in · `src/arena.ts` the one |
| 163 | live match and its sockets · `src/server.ts` the door · `static/` the browser client — |
| 164 | `val.js` wires the socket, the keys and the HUD, `raycast.js` is the ray |
| 165 | maths, `scene.js` the first-person view, `slices.js` batches its wall |
| 166 | columns, `resolution.js` and `budget.js` decide how wide to draw it, |
| 167 | `presence.js` fades bodies into sight and marks where they left it, |
| 168 | `topdown.js` the minimap, |
| 169 | `gun.js`, `beep.js`, `steer.js`, `roster.js`, `yaw.js`, `interp.js` and `prompt.js` the rest; the server bundles |
| 170 | them into one content-named file at start-up. The rules are pure functions and the tests play whole matches |
| 171 | headlessly. |
| 172 | |
| 173 | ## It only runs while somebody is there |
| 174 | |
| 175 | The match is not a daemon playing to an empty room. One beat of the clock |
| 176 | happens per tick **while at least one connection is open** — a seat or a |
| 177 | watcher — and freezes otherwise, resuming exactly where it stopped. So the |
| 178 | score you find is the score you left, nothing burns CPU on the box overnight, |
| 179 | and no round is ever decided with nobody watching it. |