matter-js / dirty fix for CCD and velocity that doesn't scale with delta ticks

Entity.js

const update = (entity, delta) => {
  const { body } = entity

  // move using `setPosition` and scale it with time since `setVelocity` doesn't scale with time (yet ?)
  Body.setPosition(
    body,
    Vector.add(
      body.position,
      Vector.mult(
        { x: 1, y: 0 },
        0.5 * delta,
      ),
    ),
  )
}

export default {
  update,
}

physics.js

const fakedFrequence = (1000 / 60) // this is what we inject into physical engine (matter)
const realFrequence = (1000 / 120) // but in real life we target this frequence, here it means we run twice the engine per frame
let tickToCatchUp = 0 // number of milliseconds to catch up in cases where delta / frequence is not a round number

const loop = (delta) => {
  // engine
  // - run the engine several times, so we have the feeling the game is fast
  // - also, this avoid collision detecting issue since CCD is not implemented yet in matter-js
  const ticks = (delta / realFrequence)
  let ticksInt = Math.floor(ticks)
  tickToCatchUp += (ticks - ticksInt)
  if (tickToCatchUp >= 1) {
    tickToCatchUp -= 1
    ticksInt += 1
  }
  for (let i = 0; i < ticksInt; i += 1) {
    // entities
    // - remove them is not alive anymore
    bodies.forEach((body) => {
      const { entity } = body

      Body.setAngle(body, 0) // FIXME: look at friction, etc on bodies to avoid them to turn instead of doing this

      if (!Entity.update(entity, realFrequence)) World.remove(engine.world, body)
    })

    // matter-js
    Engine.update(engine, fakedFrequence) // fixed frequence
  }
}

Hi thanks for this, any chance you could elaborate on how delta is computed and how the loop func is hooked into? thanks again