refactor main loop

cmd/root.go

@@ -87,6 +87,23 @@ func handleEvent(event sdl.Event, m *milkDropWindow) bool {
 	return true
 }
 
+/*
+ * update handles events and renders new frames of the visualization. It
+ * returns a bool indicating whether the program should keep running and an
+ * error, if any.
+ */
+func update(m *milkDropWindow) (bool, error) {
+	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
+		keepRunning := handleEvent(event, m)
+		if !keepRunning {
+			return false, nil
+		}
+	}
+
+	keepRunning, err := m.render()
+	return keepRunning, err
+}
+
 /*
  * milkbucket sets up the program and starts a rendering loop.
  */
@@ -119,18 +136,7 @@ func milkbucket(cmd *cobra.Command, args []string) {
 
 	running := true
 	for running {
-		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
-			running = handleEvent(event, m)
-			if !running {
-				break
-			}
-		}
-
-		if !running {
-			break
-		}
-
-		running, err = m.render()
+		running, err = update(m)
 		if err != nil {
 			panic(err)
 		}