Smooth Animation with frameend

Relevant Cesium Source

Relevant Google Earth Source (link)

function startAnimation() {
                        if (!animRunning) {
                            ge.getOptions().setFlyToSpeed(ge.SPEED_TELEPORT);
                            animRunning = true;
                            google.earth.addEventListener(ge, 'frameend', tickAnimation);

// start it off
                            tickAnimation();
                        }
                    }

function stopAnimation() {
                        if (animRunning) {
                            google.earth.removeEventListener(ge, 'frameend', tickAnimation);
                            animRunning = false;
                        }
                    }

function tickAnimation() {
                        // an example of some camera manipulation that's possible w/ the Earth API
                        var camera = ge.getView().copyAsCamera(ge.ALTITUDE_RELATIVE_TO_GROUND);
                        var dest = destination(camera.getLatitude(), camera.getLongitude(), 10, camera.getHeading());

camera.setAltitude(ANIM_ALTITUDE);
                        camera.setLatitude(dest[0]);
                        camera.setLongitude(dest[1]);

ge.getView().setAbstractView(camera);
                    }

/* Helper functions, courtesy of
                       http://www.movable-type.co.uk/scripts/latlong.html */
                    function distance(lat1, lng1, lat2, lng2) {
                        var a = Math.sin(lat1 * Math.PI / 180) * Math.sin(lat2 * Math.PI / 180);
                        var b = Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) * Math.cos((lng2 - lng1) * Math.PI / 180);
                        return 6371000 * Math.acos(a + b);
                    }

function destination(lat, lng, dist, heading) {
                        lat *= Math.PI / 180;
                        lng *= Math.PI / 180;
                        heading *= Math.PI / 180;
                        dist /= 6371000; // angular dist

var lat2 = Math.asin(Math.sin(lat) * Math.cos(dist) + Math.cos(lat) * Math.sin(dist) * Math.cos(heading));

return [180 / Math.PI * lat2, 
                                180 / Math.PI * (lng + Math.atan2(Math.sin(heading) * Math.sin(dist) * Math.cos(lat2), 
                                        Math.cos(dist) - Math.sin(lat) * Math.sin(lat2)))];
                    }