Camera 2D follow

Camera2DFollow.cs

using UnityEngine;
using System.Collections;

namespace Adnc.Cam {
	public class Camera2DFollow : MonoBehaviour {
		Vector3 currentVelocity; // Velocity used for damping camera movement

		[Tooltip("Draws debug lines representing the camera's move logic (easing only)")]
		[SerializeField] bool debug;

		[Tooltip("Creates drag when moving to a new camera point. Increasing the value results in more drag.")]
		[SerializeField] float damping = 0.25f;						

		[Tooltip("Maximum look ahead distance (how far the camera will push in front of the player when moving forward). Allows the player to look forward when moving forward.")]
		[SerializeField] float lookAheadMax = 4.5f;

		[Tooltip("How much force to apply when the camera pushes ahead of the player")]
		[SerializeField] float lookAheadForce = 0.05f;

		[Tooltip("When the character moves past this box, the camera will begin panning forward")]
		[SerializeField] float boundaryWidth = 1.8f;

		public void Stop () {
			StopAllCoroutines();
		}

		public void SetTargetLock (Transform target) {
			StopAllCoroutines();
			StartCoroutine(FollowTargetLock(target));
		}

		IEnumerator FollowTargetLock (Transform target) {
			while (target != null) {
				Sm.camera.newPos = CameraHelper.ForceZAxis(target.position);
				yield return null;
			}
		}

		public void SetTargetEase (Transform target) {
			StopAllCoroutines();
			transform.position = target.position;
			StartCoroutine(FollowTargetEase(target));
		}

		// @TODO Consider this. The screen locations for the boxes need to be scaled based on the camera size.
		// All box sizes should be -1 to 1. With 0 being dead center and 1 being the far left or right side
		IEnumerator FollowTargetEase (Transform target) {
			Vector3 lookAheadDist = Vector3.zero;
			Vector3 targetPos = CameraHelper.ForceZAxis(target.position);
			Sm.camera.newPos = transform.position;
			
			Color innerColor = Color.yellow;
			float boxPush;

			bool touchLeftInner;
			bool touchRightInner;

			Vector3 targetPrevPos = transform.position;
			Vector3 boxInnerPos = targetPos;

			// Reset current velocity since it may have an inherited value from the last time the camera was used
			currentVelocity = Vector3.zero;

			while (target != null) {
				touchLeftInner = target.position.x < boxInnerPos.x - (boundaryWidth / 2f);
				touchRightInner = target.position.x > boxInnerPos.x + (boundaryWidth / 2f);

				boxInnerPos.y = target.position.y;

				if ((touchLeftInner || touchRightInner) && target.position != targetPrevPos) {
					// Push the inner box
					boxPush = Mathf.Abs(target.position.x - targetPrevPos.x);
					boxInnerPos.x += touchRightInner ? boxPush : -boxPush;

					// The inner box was pushed, so we should snap the camera to it
					targetPos.x = boxInnerPos.x;

					// Since the camera was pushed, accumulate offset in the appropriate direction
					lookAheadDist.x += touchLeftInner ? -lookAheadForce : lookAheadForce;
					lookAheadDist.x = Mathf.Clamp(lookAheadDist.x, (boundaryWidth + lookAheadMax) / -2f, (boundaryWidth + lookAheadMax) / 2f);
				}

				// Draw debug lines
				if (debug) {
					innerColor = touchLeftInner || touchRightInner ? Color.red : Color.yellow;

					DebugExt.DrawSides(boxInnerPos, boundaryWidth, 3f, innerColor);
					DebugExt.DrawSides(target.position, lookAheadMax, 3f, Color.magenta);

					DebugExt.DrawCrosshair(targetPos, 0.2f, Color.yellow);
					DebugExt.DrawCrosshair(targetPos + lookAheadDist, 0.2f, Color.magenta);
				}

				// Always attempt to match the player's y axis position
				targetPos.y = target.position.y;

				// Move to the new position with a slight drag
				Sm.camera.newPos = Vector3.SmoothDamp(Sm.camera.newPos, CameraHelper.ForceZAxis(targetPos + lookAheadDist), ref currentVelocity, damping);

				// Track the target's old position
				targetPrevPos = target.position;

				yield return null;
			}
		}
	}
}