fix(globe): arc sphere size independent of camera zoom using inverse distance scaling

templates/tianxuan/globe.html

@@ -200,6 +200,18 @@ function updatePulses(time) {
     }
 }
 
+var refCamDist = camera.position.length();
+function updateArcScale() {
+    var dist = camera.position.length();
+    var s = refCamDist / dist;
+    for (var a = 0; a < arcData.length; a++) {
+        var sps = arcData[a].spheres;
+        for (var i = 0; i < sps.length; i++) {
+            sps[i].scale.set(s, s, s);
+        }
+    }
+}
+
 var inertiaY = 0.0005, inertiaX = 0;
 function animate() {
     requestAnimationFrame(animate);
@@ -209,6 +221,7 @@ function animate() {
     earth.rotation.y += inertiaY; arcGroup.rotation.y += inertiaY; gridGroup.rotation.y += inertiaY; borderGroup.rotation.y += inertiaY;
     earth.rotation.x += inertiaX; arcGroup.rotation.x += inertiaX; gridGroup.rotation.x += inertiaX; borderGroup.rotation.x += inertiaX;
     updatePulses(Date.now() / 1000);
+    updateArcScale();
     renderer.render(scene, camera);
 }
 animate();