WebCAD/src/Common/LightUtils.ts

import { Box3, DirectionalLight as TDirLight, Mesh, OrthographicCamera } from "three";
import { app } from "../ApplicationServices/Application";
import { DirectionalLight } from "../DatabaseServices/Lights/DirectionalLight";
import { GetBox } from "../Geometry/GeUtils";
import { CameraUpdate } from "../GraphicsSystem/CameraUpdate";

let cameraUpdate = new CameraUpdate();
cameraUpdate.SetSize(2028, 2048);
let box = new Box3();

export function DirLightShadowArea(light: DirectionalLight, calcBox = true)
{
    let direction = light.Position.clone().sub(light.Target).normalize();
    cameraUpdate.LookAt(direction.negate());

    if (calcBox)
    {
        box.makeEmpty();
        //场景内的包围盒
        for (let obj of app.Viewer.VisibleObjects)
            if (obj instanceof Mesh)
                box.union(GetBox(obj));
        cameraUpdate.ZoomExtensBox3(box);
    }

    light.DrawObject.traverse(o =>
    {
        if (o instanceof TDirLight)
        {
            o.shadow.camera.copy(cameraUpdate.Camera as OrthographicCamera);
            o.shadow.camera.updateProjectionMatrix();
        }
    });

}