miaoda-game-beam-core

Use this package for lasers and other line-shaped attacks whose geometry is fixed or swept over time. It handles the warning, active damage, fade, segment geometry, and circular-target hit test without a rendering or engine dependency.

Choose this instead of miaoda-game-shooter-core when the attack is a beam rather than a moving bullet. Angles use degrees with 0 pointing along +X.

Install

pnpm add miaoda-game-beam-core

Create and update a beam

import { Beam, sweepAngle } from 'miaoda-game-beam-core';

const beam = new Beam({
  origin: bossPosition,
  angleDeg: -60,
  length: 900,
  width: 40,
  telegraph: 1, // warning seconds
  fire: 2,      // damage seconds
  fade: 0.4,    // visual tail seconds
});

beam.tick(dtSeconds);
const fireProgress = (beam.age - 1) / 2;
beam.aim(bossPosition, sweepAngle(-60, 60, fireProgress));

if (beam.hits(playerPosition, playerRadius)) {
  damagePlayer();
}
drawLine(beam.segment(), beam.widthNow, beam.progress);

The lifecycle is telegraph -> firing -> fading -> dead:

• telegraph is visible but never damages.
• firing is the only phase in which hits can return true.
• fading remains visible but is damage-free.
• dead is ready to remove or recycle.

All durations and tick values are in seconds. Configuration coordinates, angle, geometry, and durations must be finite; tick deltas must also be non-negative. Negative finite phase durations clamp to zero. progress and widthNow are presentation values; the core does not draw anything.

Manage many beams

import { BeamSet } from 'miaoda-game-beam-core';

const beams = new BeamSet();
beams.spawn(config);

const { alive, removed } = beams.tick(dtSeconds);
const hits = beams.beamsHitting(playerPosition, playerRadius);

Use BeamSet when a boss, turret group, or spell system owns multiple active beams. Remove or recycle the entries in removed; alive contains the still-active beams for rendering and tracking.

Geometry helpers

• pointToSegmentDistance(point, start, end) measures distance to a beam segment.
• sweepAngle(fromDeg, toDeg, t) interpolates the shortest angular route for t from 0 to 1.
• directionFromAngle(angleDeg) converts the shared degree convention to a unit vector.

The core reports hits only. Damage, invulnerability frames, hit de-duplication, and collision response remain game-owned.