UrZoo Developer Diary: Zoo Sharing & Cloud Storage (pt.2)

By Will Bolam: Lead Programmer

In my previous diary I explained how we integrated Facebook into UrZoo to create an in game screen showing the player all of their friends. The next step was to let the player visit their friend’s zoos.

Traditionally, and indeed on every other games I have worked on over the last 10 years, a player’s save data is stored locally on the device on which they are playing the game. This is great for speed and security, but no good at all for sharing that save data with other players! In order to share player’s zoos we needed to store the save data online, ‘in the cloud’. Every time a player saves their zoo it is saved to the cloud, and then when another player wants to visit that zoo they can download the zoo from the cloud and interact with it in game.

We looked at a number of online data storage services, as well as considering building our own, and eventually decided to use Amazon Web Service’s Simple DB (http://aws.amazon.com/simpledb/). We chose Simple DB as it was cheap (at least until usage becomes very large) and highly scalable to meet demand in the future. Another factor in favour of Simple DB was that there was an iOS library that we could use (http://simpledb.ios-aws.com/home/download) to reduce the amount of code we needed to write to get everything up and running.

With this sytem integrated, players could visit the zoos of their Facebook friends playing UrZoo. The final part to implement was to allow players to interact with their friend’s zoos, and for their friend’s to see these interactions happen. We created a set of behaviours that players could perform, including petting and giving treats to friend’s animals, watering friend’s crops and helping out in friend’s refreshment stalls. We also allow friend’s to award kudos (our harder-to-obtain in-game currency) to zoo’s they have visited, so players can choose to reward their friend’s zoos if they have enjoyed visiting! When a player returns back to their own zoo, we save the visitor interactions to the cloud using Simple DB ready to be downloaded by the friend next time they load their zoo.

Having created all this we still have more ideas to implement, we really believe that one of the most fun elements of our game is going to be showing your zoo off to your mates so we are looking into ways for players to message each other within zoos, and also for players to sell each other exotic animals they may have created!