Celebrations and fireworks!

The coin collection game is nearly finished. Coins can be collected and a timer expires, but the win condition itself is not truly handled. That is, when all coins are collected before time expiry, nothing actually happens to show the player that they've won. The countdown still proceeds and even restarts the level as though the win condition hadn't been satisfied at all. Let's fix this now. Specifically, when the win scenario happens, we should delete the timer object to prevent further countdown and show visual feedback to signify that the level has been completed. In this case, I'll add some fireworks! So, let's start by creating the fireworks. You can add these easily from the Unity Particle System packages. Navigate to the Standard Assets | ParticleSystems | Prefabs folder. Then, drag and drop the Fireworks particle system in Scene.

Add a second or even a third one if you want:

Figure 2.29: Adding two Fireworks prefabs

By default, all firework particle systems will play when the level begins. You can test this by pressing play on the toolbar. This is not the behavior that we want. We only want the fireworks to play when the win condition has been satisfied. To disable playback on level startup, select the Particle System object in the Scene and, from the Object Inspector, disable the Play On Awake checkbox, which can be found in the Particle System component.

See Figure 2.30, Disabling Play On Awake:

Figure 2.30: Disabling Play On Awake

Disabling Play On Awake prevents particle systems playing automatically at level startup. This is fine, but if they are ever to play at all, something must manually start them at the right time. We can achieve this through code. Before resorting to a coding solution, however, we'll first mark all firework objects with an appropriate tag. The reason for this is that, in code, we'll want to search for all firework objects in the scene and trigger them to play when needed. To isolate the firework objects from all other objects, we'll use tags. So, let's create a new Fireworks tag and assign them to the firework objects only in the Scene.

Tags were created earlier in this chapter when configuring the player character for coin collisions. See Figure 2.31:

Figure 2.31: Tagging firework objects

With the firework objects now tagged, we can refine the Coin.cs script class to handle a win condition for the scene, as shown in Code Sample 2.7. Comments follow:

//-------------------------
using UnityEngine;
using System.Collections;
//-------------------------
public class Coin : MonoBehaviour
{
  //-------------------------
  public static int CoinCount = 0;
  //-------------------------
  // Use this for initialization
  void Awake () 
  {
    //Object created, increment coin count
    ++Coin.CoinCount;
  }
  //-------------------------
  void OnTriggerEnter(Collider Col)
  {
    //If player collected coin, then destroy object
    if(Col.CompareTag("Player"))
      Destroy(gameObject);
  }
  //-------------------------
  void OnDestroy()
  {
    --Coin.CoinCount;

    //Check remaining coins
    if(Coin.CoinCount <= 0)
    {
      //Game is won. Collected all coins
      //Destroy Timer and launch fireworks
      GameObject Timer = GameObject.Find("LevelTimer");
      Destroy(Timer);

      GameObject[] FireworkSystems = GameObject.FindGameObjectsWithTag("Fireworks");
      foreach(GameObject GO in FireworkSystems)
      GO.GetComponent<ParticleSystem>().Play();
    }
  }
  //-------------------------
}
//-------------------------