我正在开发一个使用高度贴图创建三维地形的可视化，并希望为地图上的城市位置添加一些标记。我猜某种raycaster和intersectObject可能会这样做，但我很遗憾如何将标记直接放在地形表面上。例如，我知道一个城市在我的纹理的像素单位（640,480），所以我做的事情如下：
// This is the terrain, loaded from a PNG of the digital elevation model
var planeGeo = new THREE.PlaneGeometry( bumpTexture.image.width, bumpTexture.image.height, 600, 450 );
var plane = new THREE.Mesh( planeGeo, customMaterial );
plane.rotation.x = -Math.PI / 2;
plane.position.y = 0;
scene.add( plane );
// At (640, 480) of the image, there should be a marker directly on top of the mesh.
var cube = new THREE.Mesh( new THREE.CubeGeometry( 20, 20, 20 ), new THREE.MeshNormalMaterial() );
cube.position.x = 640;
cube.position.y = 0;
cube.position.z = 480;
scene.add(cube);
raycaster.setFromCamera(cube, camera );
var intersects = raycaster.intersectObject(plane);
console.log(raycaster, intersects);
// no intersects???
任何建议，Threejs巫师？