Lane.cs

Source file unity-csharp/arcade-classics/frogger/Lane.cs from the GDnD code examples. Download raw file

// GDnD wiki example
// Demonstrates: timer-driven spawning of moving hazards from one screen edge, per lane
// Related pages: [[overview-arcade-classics-as-learning-projects]], [[monobehaviour-lifecycle]]
 
using UnityEngine;
 
// A single horizontal lane. On a timer it spawns one hazard at the entry edge and
// launches it across at the lane's speed. The sign of the speed decides the
// direction (and therefore which edge it enters from). Safe lanes spawn nothing.
// The game adds and configures these at runtime.
public class Lane : MonoBehaviour
{
    private FroggerGame.LaneType type;
    private float speed;
    private float spawnInterval;
    private Hazard hazardPrefab;
    private float laneY;
    private float spawnTimer;
    private Camera cachedCamera;
 
    public void Configure(FroggerGame.LaneType laneType, float laneSpeed, float interval, Hazard prefab, float y)
    {
        type = laneType;
        speed = laneSpeed;
        spawnInterval = interval;
        hazardPrefab = prefab;
        laneY = y;
        cachedCamera = Camera.main;
 
        // Stagger the first spawn so lanes do not all fire on the same frame.
        spawnTimer = Random.Range(0f, Mathf.Max(0.01f, spawnInterval));
    }
 
    private void Update()
    {
        if (hazardPrefab == null || spawnInterval <= 0f)
        {
            return;
        }
 
        spawnTimer += Time.deltaTime;
        if (spawnTimer >= spawnInterval)
        {
            spawnTimer -= spawnInterval;
            Spawn();
        }
    }
 
    private void Spawn()
    {
        float halfWidth = cachedCamera.orthographicSize * cachedCamera.aspect;
        float entryX = speed >= 0f ? -halfWidth - 1f : halfWidth + 1f;
 
        Hazard hazard = Instantiate(hazardPrefab, new Vector3(entryX, laneY, 0f), Quaternion.identity, transform);
        hazard.Launch(new Vector2(speed, 0f));
    }
}