Object Behaviors and GUI

The camera (Size 100), hero, eggs, enemy spawning and collisions, status text and Q all behave exactly as in Exercise 2, with these changes:

• Eggs are also destroyed when they hit a (visible) waypoint.
• Enemies now move: they patrol the waypoints (below).
• The hero does not collide with waypoints; it simply passes over them.

A UI bar shows how much of the 0.2-second egg cool-down is left:

• Right after an egg is fired, the bar is 200 pixels wide.
• It shrinks gradually to 0 pixels over the 0.2 seconds, when the next egg is allowed.
• Place it in the UI (e.g., under the status text).

Six waypoint objects, named A to F, each an image sprite at Transform Scale (8, 8, 1) showing its letter (the WayPointLabels images in EX3_Textures.zip), at:

• Every enemy travels along its own transform.up at a constant 20 units/second.
• At all times an enemy has a target waypoint. A newly spawned enemy starts with a random target.
• Each frame, it turns gradually toward the target by calling PointAtPosition() from Module 3.1 with a rate of 1.5 per second, i.e., PointAtPosition(target, 1.5f * Time.smoothDeltaTime).
• When an enemy comes within 25 units of its target, it picks the next waypoint as its new target and starts turning toward it.
• If the target waypoint is re-positioned (after its 4th hit), the enemy heads for the new position.

// Module 3.1: gradually turn transform.up toward p, at rate r
// (v is normalized, so the turning speed doesn't depend on distance)
private void PointAtPosition(Vector3 p, float r)
{
    Vector3 v = (p - transform.localPosition).normalized;
    transform.up = Vector3.LerpUnclamped(transform.up, v, r);
}

Everything from EX2, plus the waypoint mode (Sequence/Random). For example:

HERO: Drive(Mouse)  TouchedEnemy(3)
EGG: OnScreen(12)
ENEMY: Count(10)  Destroyed(7)
WAYPOINTS: (Sequence)

Give each waypoint a BoxCollider2D with Is Trigger checked, like the enemies. In the waypoint's OnTriggerEnter2D, respond only to eggs, so the hero passes over. To stop a hidden waypoint from being hit, disable its collider as well as its SpriteRenderer.

Same idea as EX2: copy SpriteRenderer.color, subtract 0.25 from the copy's a, and assign it back.

The object that knows all six waypoints and the current mode (for example the Game Manager) can provide a NextWaypoint(current) function that the enemies call. For random mode, pick among the other five.

An enemy turns slowly, so it can't hit a waypoint exactly. Switching targets when it gets close makes it curve smoothly on to the next one.

The cool-down bar lives in a Canvas, so its RectTransform is in pixels; the hero, eggs, enemies and waypoints are in world units. Switch between the two in the Scene view with the 2D view and by double-clicking the Canvas or Main Camera in the Hierarchy.

• Show each enemy's current target letter in the status text or above the enemy.
• Let the player change the turn rate at run time and see how the patrol paths change.

One submission per team:

1. A zip file named TeamNameEX3.zip containing your entire project: every file in Assets, Packages and ProjectSettings, and nothing more.
2. A separate folder with your PC EXE build. We'll double-click the EXE to run your project.

List every team member's name in the submission comment and at the top of your enemy script.

Self-check before you submit

• I unzipped our zip into a new, empty folder and opened it in Unity 6000.3.11f1. It opens and runs.
• The zip has only Assets, Packages and ProjectSettings.
• Double-clicking the EXE runs the game, and Q quits it.
• All EX2 features still work, including mouse mode and the egg count.
• The cool-down bar shrinks from 200 pixels to 0 every time an egg is fired.
• Four egg hits move a waypoint, but never more than 15 units from its starting position.
• With the waypoints hidden (H), eggs fly through them and enemies still patrol.
• In sequence mode, enemies visit A, B, C, D, E, F in order; in random mode, never the same waypoint twice in a row.
• The hero passes over waypoints without affecting them.
• Our enemy script lists the team members and has the 2–3 sentence explanation comment.