HarmonyOS鸿蒙Next中如何获取node节点的世界坐标

尊敬的开发者，您好，node节点位置坐标也可以代表世界坐标节点坐标，详细参考：node

Node

3D场景由树状层次结构的节点组成，其中每个节点都实现了Node接口。继承自SceneResource。

属性

系统能力： SystemCapability.ArkUi.Graphics3D

示例代码如下：

import {
  Image,
  Shader,
  MaterialType,
  Material,
  ShaderMaterial,
  Animation,
  Environment,
  Container,
  SceneNodeParameters,
  LightType,
  Light,
  Camera,
  SceneResourceParameters,
  SceneResourceFactory,
  Scene,
  Node,
  Vec3
} from '@kit.ArkGraphics3D';
import { LengthMetrics } from '@kit.ArkUI';

@Entry
@Component
 struct Index {
  scene: Scene | null = null;
  @State sceneOpt: SceneOptions | null = null;
  cam: Camera | null = null;
  @State x: number = 0
  @State y: number = 0
  @State z: number = 0

  aboutToAppear(): void {
    this.Init();
  }

  Init(): void {
    if (this.scene == null) {
      // 加载模型，将gltf文件放置到相关路径，加载时以实际路径为准
      Scene.load($rawfile("box.glb"))
        .then(async (result: Scene) => {
          this.scene = result;
          let rf: SceneResourceFactory = this.scene.getResourceFactory();
          // 创建相机
          this.cam = await rf.createCamera({ "name": "Camera" });
          // 设置合适的相机参数
          this.cam.enabled = true;
          this.sceneOpt = { scene: this.scene, modelType: ModelType.SURFACE } as SceneOptions;

          if (result && result.root) {
            let targetNode = result.root.getNodeByPath(`Scene/Cube`)
            if (targetNode) {
              console.info(`节点的世界坐标为: x=${targetNode.position.x}, y=${targetNode.position.y}, z=${targetNode.position.z}`);

              let worldPos: Vec3 = targetNode.position;

              // 2. 向上追溯父节点，累加其坐标得到绝对世界坐标
              let parent = targetNode.parent;
              while (parent && parent !== result.root) {
                worldPos.x += parent.position.x;
                worldPos.y += parent.position.y;
                worldPos.z += parent.position.z;
                parent = parent.parent;
              }

              console.info(`节点的世界坐标为: x=${worldPos.x}, y=${worldPos.y}, z=${worldPos.z}`);
            }
          }
        })
        .catch((reason: string) => {
          console.log(reason);
        });
    }
  }

  build() {
    Flex({ direction: FlexDirection.Column }) {
      if (this.sceneOpt) {
        // 通过Component3D呈现3D场景
        Component3D(this.sceneOpt)
          .flexGrow(1).flexBasis(1).flexShrink(1)

        Flex({ space: { main: LengthMetrics.vp(5), cross: LengthMetrics.vp(5) } }) {
          Column() {
            Row() {
              Text(`x:${this.x.toFixed(1)}`)
              Slider({
                value: this.x,
                min: -50,
                max: 50,
                step: 0.1,
                style: SliderStyle.OutSet
              }).onChange((value: number) => {
                if (this.cam) {
                  this.x = this.cam.position.x = value
                }
              }).showSteps(true)
            }

            Row() {
              Text(`y:${this.y.toFixed(1)}`)
              Slider({
                value: this.y,
                min: -50,
                max: 50,
                step: 0.1,
                style: SliderStyle.OutSet
              }).onChange((value: number) => {
                if (this.cam) {
                  this.y = this.cam.position.y = value
                }
              }).showSteps(true)
            }

            Row() {
              Text(`z:${this.z.toFixed(1)}`)
              Slider({
                value: this.z,
                min: -50,
                max: 50,
                step: 0.1,
                style: SliderStyle.OutSet
              }).onChange((value: number) => {
                if (this.cam) {
                  this.z = this.cam.position.z = value
                }
              }).showSteps(true)
            }
          }
        }

      } else {
        Text("loading ...")
      }
    }.width('100%').height('100%')
  }
}