This week, once we made the final finishing touches to Amazing Racer, we took at look at a small project which introduced a number of new concepts, which are very useful when building games:

• Creating objects at run-time
• Creating a coroutine
• Using random values
• Using array parameters to specify multiple values

To create object at run-time, we saw the Instantiate method. This method is provided with a reference to an existing game object or prefab and it will create a new copy of it in the scene. Optionally, a new position and a new rotation can be specified for the duplicated object. The Unity documentation has more information on Instantiate.

A coroutine is a special kind of method. It is a method that can do some work, relinquish control temporarily to the game engine for a period, and then continue from where it left off. It has the special return type of IEnumerator. By calling yield return it can relinquish control. By calling yield return new WaitForSeconds(n) it can relinquish control for a specific period of time. To start a coroutine, we use the StartCoroutine method. You can read the Unity documentation for more information on coroutines.

We saw how Random.Range(min, max) can be used to give a random value between a maximum and minimum. This randomness can add interest and naturalism to our scene. The Unity manual reference for the Random class is here. You will see that there are many other ways to get random values, apart from the Range method.

Finally, we saw how a parameter can be an array. We used an array to specify multiple game objects which could be created by our source object. In the source our property objectsToSpawn is an array, as indicated by the square brackets [].

In the inspector panel, we can see Objects To Spawn which offers a size that can be set, in this case we’ve entered 3, and as many boxes as the array is large.

The Coroutine Test project is available here.

Our completed Amazing Racer project is available here.

Finally, I was asked to provide the completed Roll-A-Ball project too. That’s here.

All these projects are compatible with Unity V5.3.2f1.

We look forward to seeing you in two weeks! Remember to work on your game ideas over the break!

We had an enjoyable session today and we were indebted to Chris for his drone demonstration.

In the Unity group, we looked at how the player could be automatically placed at the spawn point at the start of the game and returned there should they fall into the water at any point. We also saw how a sound effect can be added to help the user understand that they’ve been teleported when this occurs.

The whoosh sound effect that I created can be downloaded from here. For those who weren’t there today: I simply recorded myself making a whooshing noise with my mouth. I then used a freeware, cross-platform, program called Audacity to remove the silence at the start and end of what I’d recorded and to add a few random effects until the sound was less human-sounding and more game appropriate. Audacity can be found here, for anyone who wishes to play around with sound effects.

We added a finish point and surrounded it with a sphere collider; this is to detect when the user reaches the finish point beyond all the small lakes.

We also added some fireworks to draw the players eye to the finish zone, so that the user instinctively knows to head in that direction once the game starts.

Finally, we saw how to stop the user moving at the start of the game until a start button is pressed. We will expand on the techniques shown here to show the time taken to cross the map, to allow the user to see their best time and to restart the game. When that’s done, our game will be complete.

The project I uploaded late last week to Dropbox has been updated with all the changes from today. It includes the sound file I described earlier. It also has the latest version of the Standard Assets, which have recently been updated to Version 1.1. You can download the updated project from here. Please remember: install the latest version of Unity before opening this project!

One final note: the fireworks are currently disabled in the project. While they work perfectly, from a player perspective when the game is running, a bug in Unity Version 5.3.1f1 means that they generate a huge number of console errors. It’s fine to enable them when you want to run and hopefully we will be able to switch them on again permanently after the next program update without any console errors.

See you all next week!