rook/val Public Public: anyone can read this; nobody can change it.

/**

 * The gun in your hands: a crosshair, a shape at the bottom of the screen

 * that kicks when you fire, and a marker when a shot of yours lands.

 *

 * The client never decides whether it hit anything — it reads that off the

 * shots the server sent, the same ones the top-down view draws.

 */

/** `owed` is how many kicks have been shown ahead of the server saying a shot happened. */

export const makeGun = () => ({ kick: 0, mark: 0, ammo: null, owed: 0 });

/** Recoil and the hit marker both fade the same way: fast, and to zero. */

export const fade = (value, dt, life) => Math.max(0, value - dt / life);

/** A shot happened when the magazine went down, never when it was reloaded. */

export const firedNow = (before, ammo, reloading) =>

  before !== null && !reloading && ammo < before;

/** One of my shots landed: it started where I am standing and the server says it hit. */

export function hitMarked(shots, me) {

  for (const shot of shots) {

    if (!shot.hit) continue;

    if (Math.hypot(shot.x1 - me.x, shot.y1 - me.y) < 30) return true;

  }

  return false;

}

/**

 * The trigger was pulled here, now. If the gun can fire — alive, loaded, not

 * reloading — it kicks at once rather than a round trip later, and the kick

 * the server's snapshot would have given for the same shot is owed and not

 * shown twice. Whether the shot lands, and whether it even happened, is the

 * server's alone: a kick is the hand, not the bullet.

 */

export function gunFire(gun, snap) {

  if (!snap.me.alive || snap.me.reloading || snap.me.ammo <= 0) return false;

  if (gun.kick > 0.5) return false; // a held trigger, not a new pull

  gun.kick = 1;

  gun.owed += 1;

  return true;

}

/** Fold a fresh snapshot into the gun's state: kick on a shot, mark on a hit. */

export function gunSnapshot(gun, snap) {

  if (firedNow(gun.ammo, snap.me.ammo, snap.me.reloading)) {

    if (gun.owed > 0) gun.owed -= 1;

    else gun.kick = 1;

  }

  // A kick owed for longer than a shot could take to come back was refused.

  if (gun.owed > 0 && gun.kick === 0) gun.owed = 0;

  if (snap.me.alive && hitMarked(snap.shots, snap.me)) gun.mark = 1;

  gun.ammo = snap.me.ammo;

}

export function gunTick(gun, dt) {

  gun.kick = fade(gun.kick, dt, 0.12);

  gun.mark = fade(gun.mark, dt, 0.35);

}

/** The crosshair, the weapon and the marker, in that order of importance. */

export function drawGun(ctx, gun, width, height, snap) {

  const cx = width / 2;

  const cy = height / 2;

  const gap = 6 + gun.kick * 10;

  const arm = 9;

  ctx.lineWidth = 2;

  ctx.strokeStyle = "rgba(20,24,30,0.8)";

  ctx.beginPath();

  for (const [dx, dy] of [

    [1, 0],

    [-1, 0],

    [0, 1],

    [0, -1],

  ]) {

    ctx.moveTo(cx + dx * gap, cy + dy * gap);

    ctx.lineTo(cx + dx * (gap + arm), cy + dy * (gap + arm));

  }

  ctx.stroke();

  ctx.strokeStyle = snap.me.alive ? "#8ef0c4" : "#888";

  ctx.lineWidth = 1.4;

  ctx.stroke();

  if (gun.mark > 0) {

    ctx.strokeStyle = `rgba(255,120,110,${gun.mark})`;

    ctx.lineWidth = 2.5;

    ctx.beginPath();

    for (const [dx, dy] of [

      [1, 1],

      [-1, -1],

      [1, -1],

      [-1, 1],

    ]) {

      ctx.moveTo(cx + dx * 7, cy + dy * 7);

      ctx.lineTo(cx + dx * 15, cy + dy * 15);

    }

    ctx.stroke();

  }

  if (!snap.me.alive) return;

  // The weapon: a barrel and a body, off to the right, rising with the kick.

  const scale = height / 570;

  const lift = gun.kick * 22 * scale + (snap.me.reloading ? 40 * scale : 0);

  const bx = width * 0.66;

  const by = height + lift;

  ctx.fillStyle = "#23262e";

  ctx.beginPath();

  ctx.moveTo(bx - 34 * scale, by);

  ctx.lineTo(bx - 20 * scale, by - 130 * scale);

  ctx.lineTo(bx + 16 * scale, by - 150 * scale);

  ctx.lineTo(bx + 30 * scale, by - 40 * scale);

  ctx.lineTo(bx + 60 * scale, by);

  ctx.closePath();

  ctx.fill();

  ctx.fillStyle = "#3b414e";

  ctx.fillRect(bx - 8 * scale, by - 160 * scale, 22 * scale, 26 * scale);

  if (gun.kick > 0.35) {

    ctx.fillStyle = `rgba(255,220,140,${gun.kick})`;

    ctx.beginPath();

    ctx.arc(bx + 3 * scale, by - 162 * scale, 18 * scale * gun.kick, 0, 7);

    ctx.fill();

  }

}