PHYSICS/physics.ts

import IParams from "./IParams.ts";
import IPoint from "./IPoint.ts";

function getV0(params: IParams) {
  return Math.sqrt(2 * params.g * params.h);
}

function getCollisionPoints(params: IParams): IPoint[] {
  const interpolationPoints = interpolation(params);
  const points: IPoint[] = [];

  for (let i = 0; i < interpolationPoints.length - 1; i++) {
    if (interpolationPoints[i].angle - interpolationPoints[i+1].angle < 0) {
      points.push(interpolationPoints[i]);
    }
  }

  return [{x: 0, y: 0, angle: 0, velocity: 0, time: 0}, ...points];
}

function interpolation(params: IParams): IPoint[] {
  const T = (2 * getV0(params)) / params.g;

  const points: IPoint[] = [];
  let lastX = 0;

  let i = 0;
  while (lastX*Math.cos(params.alpha) < params.l) {
    const t = i / 100;

    const vx = getV0(params)*Math.sin(params.alpha) + params.g*Math.sin(params.alpha)*t;
    const vy = getV0(params)*Math.cos(params.alpha) - params.g*Math.cos(params.alpha)*(t % T);

    lastX = getV0(params) * Math.sin(params.alpha) * t + (params.g * Math.sin(params.alpha) * t ** 2) / 2;

    points.push({
      x: lastX,
      y: getV0(params) * Math.cos(params.alpha) * (t % T) - (params.g * Math.cos(params.alpha) * (t % T) ** 2) / 2,
      time: t,
      velocity: Math.sqrt(vx*vx + vy*vy),
      angle: Math.atan2(vy, vx)
    });
    i++;
  }

  return points;
}

function firstPoint(params: IParams): IPoint[] {
  const points: IPoint[] = [
    {
      x: 0,
      y: 0,
      time: 0,
      angle: -Math.PI / 2,
      velocity: 0
    }
  ];

  let t = 0.01;
  while(points[points.length - 1].y >= -params.h) {
    points.push({
      x: 0,
      y: -params.g*t**2,
      time: t,
      angle: -Math.PI / 2,
      velocity: -params.g*t
    })
    t += 0.01;
  }

  return points.slice(0, points.length-1);
}

export { getCollisionPoints, interpolation, firstPoint };