mrdoob/three.js#29353

line2.ts

import * as THREE from "three";

function isLineBasicMaterial(mat: THREE.Material & { isLineBasicMaterial?: boolean }): mat is THREE.LineBasicMaterial {
  return Boolean(mat.isLineBasicMaterial);
}

function isOrthographicCamera(camera: THREE.Camera & { isOrthographicCamera?: boolean }): camera is THREE.OrthographicCamera {
  return Boolean(camera.isOrthographicCamera);
}

// Returns the maximum line width in `mat`, or undefined.
function getLineWidth(mat: THREE.Material | THREE.Material[]) {
  if (Array.isArray(mat)) {
    let maxWidth = 0;

    for (const m of mat) {
      if (isLineBasicMaterial(m) && m.linewidth > maxWidth) {
        maxWidth = m.linewidth;
      }
    }
  } else {
    if (isLineBasicMaterial(mat)) {
      return mat.linewidth;
    }
  }

  return undefined;
}

interface ExtendedRaycasterParameters extends THREE.RaycasterParameters {
  Line: THREE.RaycasterParameters["Line"] & {
    // Whether to perform ray casting based on `LineBasicMaterial`
    // properties.
    material?: boolean;
  };
}

// Returns the type-cast parameters.
export function getExtendedRaycasterParams(raycaster: THREE.Raycaster) {
  return raycaster.params as ExtendedRaycasterParameters;
}

// A Line that can perform ray casting based on
// `LineBasicMaterial.linewidth`. This behavior is enabled if
// `raycaster.params.Line.screenSpace` is true.
//
// Workaround for https://github.com/mrdoob/three.js/issues/29353.
export class Line2 extends THREE.Line {
  override raycast(raycaster: THREE.Raycaster, intersects: THREE.Intersection[]) {
    const params = getExtendedRaycasterParams(raycaster).Line;

    if (params.material) {
      if (!this.material) return undefined;

      let lw = getLineWidth(this.material);
      if (lw === undefined) return undefined;
      if (isOrthographicCamera(raycaster.camera)) {
        lw /= raycaster.camera.zoom;
      }

      params.threshold = lw;
    }

    return super.raycast(raycaster, intersects);
  }
}