applyBehaviour(particle, time, index) {
    this.calculate(particle, time, index);

    if (!this.same) {
      if (this.style === "to" || this.style === "TO" || this.style === "_") {
        particle.rotation +=
          particle.data.rotationB + (particle.data.rotationA - particle.data.rotationB) * this.energy;
      } else {
        particle.rotation += particle.data.rotationB;
      }
    } else if (this.a.a === "V" || this.a.a === "Velocity" || this.a.a === "v") {
      // beta...
      particle.rotation = particle.getDirection();
    }
  }
Applies this behaviour to a particle.
@param {object} particle - The particle to apply the behaviour to.
@param {number} time - The integrate time (1/ms).
@param {number} index - The particle index.