title: OpenLayers Map as texture on THREE.js plane
body: <p>I am looking to use an OpenLayers map as a texture for a plane in THREE.js. I know you can load a canvas element as texture for a plane material, so I've tried different ways of accomplishing that but with no success. First I create a canvas element in the DOM, with a <code>id=map</code>. Then, I create a map on it:</p>
  
  <pre><code>  const layers = [
        new ol.layer.Tile({
           source: new ol.source.OSM()
        })
    ];
    const map = new ol.Map({
        layers: layers,
        target: 'map',
        view: new ol.View({
           center: [-10997148, 4569099],
           zoom: 4
        })
    });
  </code></pre>
  
  <p>And then I attempt to load the map as texture in my THREE scene like:</p>
  
  <pre><code>const texture = new THREE.Texture(canvas);
  texture.needsUpdate = true;
  const material = new THREE.MeshBasicMaterial({ map : texture, });
  const plane = new THREE.Mesh(geometry, material);
  
  scene.add(this.plane);
  </code></pre>
  
  <p>When doing so, I can only see a black plane. The rest of elements in the scene render properly, and I can see the map perfectly fine in the 2D canvas element. If instead of using an OpenLayers map I draw on the canvas with <code>fillRect</code> or something like that, the plane gets the texture well. What am I doing wrong? (I'm using OL3 and THREE r71)</p>