examples/vr_crop/vr_crop.js
function animate() {
    // render
    controls.update();

    if (ready && modified) {
      renderer.render(sceneT, camera, rtTexture, true);
      renderer.render(scene, camera);
      modified = false;
    }

    stats.update();

    // request new frame
    requestAnimationFrame(function() {
      animate();
    });
  }
function animate() {
    // render
    controls.update();

    if (ready && modified) {
      renderer.render(sceneT, camera, rtTexture, true);
      renderer.render(scene, camera);
      modified = false;
    }

    stats.update();

    // request new frame
    requestAnimationFrame(function() {
      animate();
    });
  }
this function is executed on each animation frame