prendy/src/helpers/babylonjs/pointIsInside.ts

Make games with prerendered backdrops using babylonjs and repond

import {
  AbstractMesh,
  Axis,
  DeepImmutableObject,
  // Mesh,
  Ray,
  Vector3,
} from "@babylonjs/core";

// Check When a Point is Inside a Mesh
// from https://doc.babylonjs.com/toolsAndResources/utilities/IsInside

const RAY_LIMIT = 100;
const SCALE_DOWN_AMOUNT = 0.00001; // originally 0.00000001 but caused too many iterations

// const ray = new Ray(Vector3.Zero(), Axis.X, 2);

export default function pointIsInside(point: Vector3, mesh: AbstractMesh) {
  // return false;
  let boundInfo = mesh.getBoundingInfo();
  // let max = boundInfo.maximum;
  // let min = boundInfo.minimum;
  let diameter = 2 * boundInfo.boundingSphere.radius;
  // if (point.x < min.x || point.x > max.x) {
  //   return false;
  // }
  // if (point.y < min.y || point.y > max.y) {
  //   return false;
  // }
  // if (point.z < min.z || point.z > max.z) {
  //   return false;
  // }

  if (!mesh.intersectsPoint(point)) return false;

  let pointFound = false;
  // let d = 0;
  let hitCount = 0;
  // let gap = 0;
  // let distance = 0;
  let ray = new Ray(Vector3.Zero(), Axis.X, diameter);
  let pickInfo;
  let direction = point.clone();
  let refPoint = point.clone();

  // let rayDistance = null as null | number;

  hitCount = 0;
  ray.origin = refPoint;
  ray.direction = direction;
  ray.length = diameter;
  pickInfo = ray.intersectsMesh(mesh as any);
  while (pickInfo.hit && hitCount < RAY_LIMIT) {
    hitCount++;
    pickInfo.pickedPoint?.addToRef(direction.scale(SCALE_DOWN_AMOUNT), refPoint);
    ray.origin = refPoint;
    pickInfo = ray.intersectsMesh(mesh as any);
  }

  if (hitCount % 2 === 1) pointFound = true;

  return pointFound;
}