siege-protocol/js/weapon-projectiles.js

// ═══ weapon-projectiles.js ═══
// ============================================================
//  WEAPON PROJECTILES — projectile, beam, AoE, and chain updates
// ============================================================

// ── UPDATE PROJECTILES ────────────────────────────────────────
function updateProjectiles() {
  const W = canvas.width, H = canvas.height;
  const cx = W / 2, cy = H / 2;

  for (const p of G.projectiles) {
    if (p.life <= 0) continue;

    if (p.type === 'mortar') {
      // Arc toward target
      p.progress += (p.speed * 0.6) / Math.hypot(p.tx - p.sx, p.ty - p.sy);
      p.progress = Math.min(p.progress, 1);
      p.x = p.sx + (p.tx - p.sx) * p.progress;
      p.y = p.sy + (p.ty - p.sy) * p.progress;
      // Arc height
      const arc = Math.sin(p.progress * Math.PI) * 60;
      p.y -= arc;

      if (p.progress >= 1) {
        // Explode
        explodeMortar(p);
        p.life = 0;
      }
      continue;
    }

    // Homing
    if (p.homing && p.targetId) {
      let target = p.targetRef && p.targetRef.alive ? p.targetRef : null;
      if (!target) {
        for (const e of G.enemies) {
          if (e.id === p.targetId && e.alive) {
            target = e;
            p.targetRef = e;
            break;
          }
        }
      }
      if (target) {
        const angle = Math.atan2(target.y - p.y, target.x - p.x);
        const currentAngle = Math.atan2(p.vy, p.vx);
        const delta = normalizeAngle(angle - currentAngle);
        const newAngle = currentAngle + Math.sign(delta) * Math.min(Math.abs(delta), p.homingStrength);
        const spd = Math.hypot(p.vx, p.vy);
        p.vx = Math.cos(newAngle) * spd;
        p.vy = Math.sin(newAngle) * spd;
      }
    }

    p.x += p.vx;
    p.y += p.vy;

    // Out of bounds
    if (p.x < -50 || p.x > W+50 || p.y < -50 || p.y > H+50) {
      p.life = 0;
      continue;
    }

    // Hit detection
    for (const e of G.enemies) {
      if (!e.alive || e.spawnImmunity > 0) continue;
      const hitRadius = e.radius + p.radius;
      if (distSq(p.x, p.y, e.x, e.y) < hitRadius * hitRadius) {
        // Evasion check
        if (e.evasion && Math.random() < e.evasion) {
          spawnFloater(e.x, e.y - 14, 'DODGE', '#aaaaaa', 0.9);
          p.life = 0;
          break;
        }
        if (p.aoeRadius > 0) {
          explodeProjectile(p);
        } else {
          dealDamage(e, p.damage, p.elements, true, p.critChance, p.armorShred);
          if (e.hp <= 0) killEnemy(e, true);
        }

        if (p.pierceLeft > 0) {
          p.pierceLeft--;
        } else {
          p.life = 0;
          break;
        }
      }
    }
  }

  compactLiveArray(G.projectiles, p => p.life > 0);
}

function explodeMortar(p) {
  sfx_mortar_explode();
  spawnParticleBurst(p.x, p.y, p.color, 20);
  // Screen shake feel: big particle burst
  spawnParticleBurst(p.x, p.y, '#ffffff', 6);

  if (p.dotDamage > 0) {
    // Lingering zone (poison cloud)
    G.aoeZones.push({
      id: uid(),
      x: p.x, y: p.y,
      radius: p.aoeRadius,
      color: p.color,
      life: 1,
      duration: p.dotDuration || 180,
      remaining: p.dotDuration || 180,
      dotDamage: p.dotDamage,
      dotInterval: p.dotInterval || 30,
      dotTick: 0,
      elements: p.elements,
      freezeDuration: p.freezeDuration || 0,
    });
    return;
  }

  for (const e of G.enemies) {
    if (!e.alive || e.spawnImmunity > 0) continue;
    const hitRadius = p.aoeRadius + e.radius;
    if (distSq(e.x, e.y, p.x, p.y) < hitRadius * hitRadius) {
      dealDamage(e, p.damage, p.elements, false);
      if (p.freezeDuration > 0) applyFreeze(e, p.freezeDuration);
      if (e.hp <= 0) killEnemy(e, true);
    }
  }
}

function explodeProjectile(p) {
  spawnParticleBurst(p.x, p.y, p.color, 24);
  spawnParticleBurst(p.x, p.y, '#ffffff', 5);

  for (const e of G.enemies) {
    if (!e.alive || e.spawnImmunity > 0) continue;
    const hitRadius = p.aoeRadius + e.radius;
    if (distSq(e.x, e.y, p.x, p.y) < hitRadius * hitRadius) {
      dealDamage(e, p.damage, p.elements, true, p.critChance, p.armorShred);
      if (e.hp <= 0) killEnemy(e, true);
    }
  }
  p.life = 0;
}

function updateBeams() {
  compactLiveArray(G.beams, b => {
    b.life -= b.decay;
    return b.life > 0;
  });
}

function updateAoeZones() {
  for (const z of G.aoeZones) {
    z.remaining--;
    z.life = z.remaining / z.duration;
    z.dotTick++;
    if (z.dotTick >= z.dotInterval) {
      z.dotTick = 0;
      for (const e of G.enemies) {
        if (!e.alive || e.spawnImmunity > 0) continue;
        const hitRadius = z.radius + e.radius;
        if (distSq(e.x, e.y, z.x, z.y) < hitRadius * hitRadius) {
          dealDamage(e, z.dotDamage, z.elements, false);
          if (e.hp <= 0) killEnemy(e, true);
        }
      }
    }
  }
  compactLiveArray(G.aoeZones, z => z.remaining > 0);
}

// Chain arc visual helper — pushes a glowing zigzag bolt to G.chainArcs
function spawnChainArc(x1, y1, x2, y2, color) {
  const dx = x2 - x1, dy = y2 - y1;
  const len = Math.hypot(dx, dy) || 1;
  const perpX = -dy / len, perpY = dx / len;
  const steps = 10;
  const pts = [{ x: x1, y: y1 }];
  for (let i = 1; i < steps; i++) {
    const t = i / steps;
    const maxOff = 26 * Math.sin(t * Math.PI); // taper to 0 at both ends
    const off = (Math.random() - 0.5) * 2 * maxOff;
    pts.push({ x: x1 + dx * t + perpX * off, y: y1 + dy * t + perpY * off });
  }
  pts.push({ x: x2, y: y2 });
  G.chainArcs.push({ pts, color, life: 1.0, decay: 0.16 });

  // Short branch off the midpoint for realism
  const mid = pts[Math.floor(steps / 2)];
  const branchAngle = Math.atan2(dy, dx) + (Math.random() < 0.5 ? 1 : -1) * (Math.PI * 0.3 + Math.random() * 0.4);
  const branchLen = len * 0.3;
  const bpts = [{ x: mid.x, y: mid.y }];
  const bSteps = 4;
  for (let i = 1; i <= bSteps; i++) {
    const t = i / bSteps;
    const off = (Math.random() - 0.5) * 12 * Math.sin(t * Math.PI);
    bpts.push({
      x: mid.x + Math.cos(branchAngle) * branchLen * t + perpX * off,
      y: mid.y + Math.sin(branchAngle) * branchLen * t + perpY * off,
    });
  }
  G.chainArcs.push({ pts: bpts, color, life: 0.65, decay: 0.20 });
}

function updateChainArcs() {
  compactLiveArray(G.chainArcs, a => {
    a.life -= a.decay;
    return a.life > 0;
  });
}