siege-protocol/js/weapons.js

// ═══ weapons.js ═══
// ============================================================
//  WEAPONS.JS — Firing logic for all weapon types
// ============================================================

const AIM_THRESHOLD = 0.18; // radians - tighter aim requirement
const HARDPOINT_BASE_ANGLE = -Math.PI / 2;

function getHardpointOrbit(totalSlots = Math.max(1, G.tower.weaponSlots)) {
  // Wider orbit as slots increase so each hardpoint stays readable.
  return 21 + Math.min(12, totalSlots * 1.6);
}

function getSlotHardpoint(slotIndex, cx, cy, totalSlots = Math.max(1, G.tower.weaponSlots)) {
  const orbit = getHardpointOrbit(totalSlots);
  const mountAngle = HARDPOINT_BASE_ANGLE + (slotIndex / totalSlots) * Math.PI * 2;
  return {
    slotIndex,
    totalSlots,
    mountAngle,
    x: cx + Math.cos(mountAngle) * orbit,
    y: cy + Math.sin(mountAngle) * orbit,
    orbit,
  };
}

function getWeaponHardpoints(cx, cy) {
  const totalSlots = Math.max(1, G.tower.weaponSlots);
  const result = [];
  for (let slotIndex = 0; slotIndex < totalSlots; slotIndex++) {
    const weapon = G.weapons[slotIndex];
    if (!weapon) continue;
    const mount = getSlotHardpoint(slotIndex, cx, cy, totalSlots);
    result.push({ ...mount, weapon });
  }
  return result;
}

function getWeaponBarrelLength(weapon) {
  const type = getWeaponDef(weapon)?.type;
  if (type === 'beam') return 24;
  if (type === 'mortar') return 14;
  if (type === 'cone') return 15;
  if (type === 'multi') return 19;
  if (type === 'chain') return 18;
  return 17;
}

function getWeaponMuzzle(hardpoint) {
  const w = hardpoint.weapon;
  const aimAngle = typeof w.aimAngle === 'number' ? w.aimAngle : hardpoint.mountAngle;
  const barrelLen = getWeaponBarrelLength(w);
  const recoilOffset = (w.recoil || 0) * 3.2;
  const reach = Math.max(7, barrelLen - recoilOffset);
  return {
    x: hardpoint.x + Math.cos(aimAngle) * reach,
    y: hardpoint.y + Math.sin(aimAngle) * reach,
    angle: aimAngle,
  };
}

function clampAimPoint(x, y) {
  const pad = 18;
  return {
    x: Math.max(pad, Math.min(canvas.width - pad, x)),
    y: Math.max(pad, Math.min(canvas.height - pad, y)),
  };
}

function predictEnemyFuturePoint(target, framesAhead) {
  if (typeof predictEnemyPositionAlongPath === 'function') {
    return predictEnemyPositionAlongPath(target, framesAhead);
  }
  return {
    x: target.x + (target.vx || 0) * framesAhead,
    y: target.y + (target.vy || 0) * framesAhead,
  };
}

function predictInterceptPoint(ox, oy, target, projectileSpeed, maxLeadFrames = 180) {
  const speed = Math.max(0.01, projectileSpeed);

  let t = Math.hypot(target.x - ox, target.y - oy) / speed;
  t = Math.max(0, Math.min(maxLeadFrames, t));

  for (let i = 0; i < 5; i++) {
    const p = predictEnemyFuturePoint(target, t);
    const dist = Math.hypot(p.x - ox, p.y - oy);
    const nextT = Math.max(0, Math.min(maxLeadFrames, dist / speed));
    if (Math.abs(nextT - t) < 0.2) {
      t = nextT;
      break;
    }
    t = nextT;
  }

  const predicted = predictEnemyFuturePoint(target, t);
  return clampAimPoint(predicted.x, predicted.y);
}

function getLeadAimPoint(w, target, ox, oy) {
  if (!w || !target) return null;
  const def = getWeaponDef(w);
  if (!def) return { x: target.x, y: target.y };

  if (def.type === 'projectile') {
    return predictInterceptPoint(ox, oy, target, Math.max(0.1, w.projectileSpeed || 0.1), 220);
  }

  if (def.type === 'mortar') {
    // Mortar progress uses speed^2 * 0.6 in updateProjectiles.
    const ps = Math.max(0.1, w.projectileSpeed || 0.1);
    const planarSpeed = ps * ps * 0.6;
    return predictInterceptPoint(ox, oy, target, planarSpeed, 260);
  }

  return { x: target.x, y: target.y };
}

function getWeaponColor(w) {
  const el = getWeaponElements(w)[0];
  return ELEMENTS[el]?.color || getWeaponDef(w)?.color || '#fff';
}

function getIdleScanAngle(hardpoint) {
  const sweep = Math.PI / 4; // 90 degree cone, centered away from tower.
  const phase = hardpoint.slotIndex * 1.7;
  return normalizeAngle(hardpoint.mountAngle + Math.sin(G.frame * 0.0125 + phase) * sweep);
}

function updateWeapons() {
  const cx = ARENA_CX, cy = ARENA_CY;
  const hardpoints = getWeaponHardpoints(cx, cy);
  let hasPrimaryAim = false;

  for (const hardpoint of hardpoints) {
    const w = hardpoint.weapon;
    const mountAngle = hardpoint.mountAngle;

    if (typeof w.aimAngle !== 'number') w.aimAngle = mountAngle;
    if (typeof w.cooldown !== 'number') w.cooldown = 0;
    if (typeof w.recoil !== 'number') w.recoil = 0;
    if (typeof w.muzzleFlash !== 'number') w.muzzleFlash = 0;

    w.recoil *= 0.68;
    if (w.recoil < 0.01) w.recoil = 0;
    if (w.muzzleFlash > 0) w.muzzleFlash--;

    const target = pickTarget(w);
    let aimPoint = null;
    let desiredAngle = null;
    if (target) {
      aimPoint = getLeadAimPoint(w, target, hardpoint.x, hardpoint.y);
      desiredAngle = Math.atan2(aimPoint.y - hardpoint.y, aimPoint.x - hardpoint.x);
      w.aimAngle = stepTowardAngle(w.aimAngle, desiredAngle, G.tower.aimSpeed);
    } else {
      const scanDelta = shortestAngleDelta(w.aimAngle, mountAngle);
      if (Math.abs(scanDelta) > Math.PI / 4) w.aimAngle = mountAngle;
      desiredAngle = getIdleScanAngle(hardpoint);
      w.aimAngle = stepTowardAngle(w.aimAngle, desiredAngle, G.tower.aimSpeed * 0.45);
    }

    if (!hasPrimaryAim) {
      G.tower.cannonAngle = w.aimAngle;
      hasPrimaryAim = true;
    }

    if (w.cooldown > 0) {
      w.cooldown--;
      continue;
    }
    if (!target) continue;

    const dx = target.x - hardpoint.x;
    const dy = target.y - hardpoint.y;
    const dist = Math.hypot(dx, dy);
    if (dist > w.range) continue;

    let fireAngle = w.aimAngle;

    // Aim check for directional weapons.
    if (w.defId !== 'flamethrower' && w.defId !== 'laser') {
      const aimDelta = shortestAngleDelta(w.aimAngle, desiredAngle);
      if (Math.abs(aimDelta) > AIM_THRESHOLD) continue;
      // Snap to exact target angle on shot so first-round accuracy is reliable.
      fireAngle = desiredAngle;
      w.aimAngle = desiredAngle;
    } else if (desiredAngle != null) {
      fireAngle = desiredAngle;
      w.aimAngle = desiredAngle;
    }

    const muzzle = getWeaponMuzzle(hardpoint);
    fireWeapon(w, target, muzzle.x, muzzle.y, fireAngle, aimPoint);
    w.cooldown = Math.max(4, w.fireRate);
    w.recoil = 1;
    w.muzzleFlash = 4;
    w.lastFireFrame = G.frame;
  }

  if (!hasPrimaryAim) G.tower.cannonAngle = normalizeAngle((G.tower.cannonAngle || 0) + 0.006);

  // Update projectiles
  updateProjectiles();
  updateBeams();
  updateChainArcs();
  updateAoeZones();
}