.history/fetch_ex_bbox_20241120093705.js

/**
 * Fetch bounding box data from a JSON file in the specified directory.
 * @param {string} dirUrl - The directory URL where the boundingBox.json is located.
 * @returns {Promise<Array<THREE.Vector2>>} - Returns a promise resolving to an array of 2D vectors.
 */
async function fetchBoundingBox(dirUrl) {
    try {
      // Extract the base directory by removing everything after the last "/"
      const baseDir = dirUrl.split('/')[0];
  
      // Construct the full path for the boundingBox.json
      const boundingBoxPath = `${baseDir}/boundingBox.json`;
  
      // Use the loadJSONFile function to fetch the bounding box
      const jsonData = await loadJSONFile(boundingBoxPath);
  
      // Extract the sphere positions from the boundingBox data
      const spheres = jsonData.boundingBox.spheres || [];
      const vertices = spheres.map(sphere => new THREE.Vector2(sphere.x, sphere.z));
  
      return vertices;
    } catch (error) {
      console.error('Erreur lors de la récupération des données de la bounding box :', error);
      throw error;
    }
  }
  
  /**
   * Sets up camera restriction using bounding box data.
   * @param {THREE.Camera} gCamera - The camera to restrict.
   * @param {THREE.Renderer} gRenderer - The renderer for rendering the scene.
   * @param {THREE.Scene} gRayMarchScene - The scene to which restrictions are applied.
   * @param {string} dirUrl - The directory URL where the boundingBox.json is located.
   */
  async function setupCameraRestriction(gCamera, gRenderer, gRayMarchScene, dirUrl) {
    const fixedHeight = 0.5; // Fixed y-coordinate for the camera
  
    // Fetch the bounding box data
    const polygonVertices = await fetchBoundingBox(dirUrl);
  
    // Visualize the bounding box in the scene
    function createPolygonVisualization() {
      const material = new THREE.LineBasicMaterial({ color: 0x00ff00 });
      const points = [];
  
      // Convert 2D points to 3D for visualization
      polygonVertices.forEach(vertex => {
        points.push(new THREE.Vector3(vertex.x, fixedHeight, vertex.y));
      });
  
      // Close the polygon by adding the first point to the end
      points.push(new THREE.Vector3(polygonVertices[0].x, fixedHeight, polygonVertices[0].y));
  
      // Create a line geometry for visualization
      const geometry = new THREE.BufferGeometry().setFromPoints(points);
      const line = new THREE.Line(geometry, material);
      gRayMarchScene.add(line);
  
      // Add spheres to mark the vertices
      const sphereGeometry = new THREE.SphereGeometry(0.01, 16, 16);
      const sphereMaterial = new THREE.MeshBasicMaterial({ color: 0xff0000 });
      polygonVertices.forEach(vertex => {
        const sphere = new THREE.Mesh(sphereGeometry, sphereMaterial);
        sphere.position.set(vertex.x, fixedHeight, vertex.y);
        gRayMarchScene.add(sphere);
      });
    }
  
    createPolygonVisualization();
  
    // Check if a point is inside the polygon
    function isPointInPolygon(point, vertices) {
      let intersects = 0;
      for (let i = 0; i < vertices.length; i++) {
        const v1 = vertices[i];
        const v2 = vertices[(i + 1) % vertices.length];
  
        if ((v1.y > point.y) !== (v2.y > point.y) &&
          point.x < ((v2.x - v1.x) * (point.y - v1.y)) / (v2.y - v1.y) + v1.x) {
          intersects++;
        }
      }
      return intersects % 2 === 1;
    }
  
    // Restrict camera position based on bounding box
    function restrictCameraPosition() {
      gCamera.position.y = fixedHeight;
  
      const cameraPos2D = new THREE.Vector2(gCamera.position.x, gCamera.position.z);
  
      if (!isPointInPolygon(cameraPos2D, polygonVertices)) {
        let closestPoint = cameraPos2D;
        let minDistance = Infinity;
  
        for (let i = 0; i < polygonVertices.length; i++) {
          const v1 = polygonVertices[i];
          const v2 = polygonVertices[(i + 1) % polygonVertices.length];
  
          const closestPointOnEdge = closestPointOnLineSegment(cameraPos2D, v1, v2);
          const distance = cameraPos2D.distanceTo(closestPointOnEdge);
  
          if (distance < minDistance) {
            minDistance = distance;
            closestPoint = closestPointOnEdge;
          }
        }
  
        gCamera.position.x = closestPoint.x;
        gCamera.position.z = closestPoint.y;
      }
    }
  
    function closestPointOnLineSegment(point, v1, v2) {
      const lineVec = new THREE.Vector2().subVectors(v2, v1);
      const pointVec = new THREE.Vector2().subVectors(point, v1);
      const lineLen = lineVec.length();
      const lineUnitVec = lineVec.normalize();
      const projection = pointVec.dot(lineUnitVec);
      const t = Math.max(0, Math.min(lineLen, projection));
      return new THREE.Vector2().copy(v1).add(lineUnitVec.multiplyScalar(t));
    }
  
    function animate() {
      requestAnimationFrame(animate);
  
      restrictCameraPosition();
      gRenderer.render(gRayMarchScene, gCamera);
    }
  
    animate();
  }