CharacterController2D.cs

using System.Collections;
using System.IO;
using UnityEngine;

[System.Serializable]
public class CharacterController2D : MonoBehaviour {
	BoxCollider2D hitbox;
	Rigidbody2D rigidBody;

	public string statisticsFile;
	public float spawnPointX;
	public float spawnPointY;

	//character-specific values, set in the character script
	public float moveForce;
	public float stopDivisor;
	public float maxSpeed;
	public float maxFallSpeed;
	public float jumpForce;
	public int airJumps;
	public float scaleX;
	public float scaleY;

	//hitbox
	public float hitboxOffsetX;
	public float hitboxOffsetY;
	public float hitboxSizeX;
	public float hitboxSizeY;

	//shortcut values
	float hitboxLeft;
	float hitboxRight;
	float hitboxTop;
	float hitboxBottom;

	//movement
	float horizontal = 0f;
	bool jump = false;
	bool grounded = false;
	int airJumpCount = 0;

	//graphics
	float lastXSpeed = 0f;

	void Awake() {
		hitbox = GetComponent<BoxCollider2D> ();
		rigidBody = GetComponent<Rigidbody2D> ();
	}

	IEnumerator Start() {
		//hitbox
		hitbox.offset = new Vector2 (hitboxOffsetX, hitboxOffsetY);
		hitbox.size = new Vector2 (hitboxSizeX, hitboxSizeY);

		//scale
		Vector3 scale = transform.localScale;
		scale.x *= scaleX;
		scale.y *= scaleY;
		transform.localScale = scale;

		//calculate shortcuts
		hitboxLeft   = (hitboxOffsetX + hitboxSizeX/2) * scaleX;
		hitboxRight  = (hitboxOffsetX - hitboxSizeX/2) * scaleX;
		hitboxTop    = (hitboxOffsetY + hitboxSizeY/2) * scaleY;
		hitboxBottom = (hitboxOffsetY - hitboxSizeY/2) * scaleY;

		//BUG: can't jump before the first frame for some reason
		yield return null;
		Respawn ();
	}

	void Update() {
		//determine if on the ground
		grounded  = Physics2D.Linecast(transform.position, transform.position + new Vector3( hitboxLeft, hitboxBottom - 0.01f, 0), 1 << LayerMask.NameToLayer("World"));
		grounded |= Physics2D.Linecast(transform.position, transform.position + new Vector3(hitboxRight, hitboxBottom - 0.01f, 0), 1 << LayerMask.NameToLayer("World"));

		//get horizontal speed, potentially negative
		horizontal = Input.GetAxis ("Horizontal");

		if (grounded) {
			airJumpCount = 0;
		}

		//determine if jumping
		if (Input.GetButtonDown ("Jump") && (grounded || airJumps > airJumpCount)) {
			jump = true;
		}
	}

	void FixedUpdate() {
		//move in the inputted direction, if not at max speed
		if (horizontal * rigidBody.velocity.x < maxSpeed) {
			rigidBody.AddForce (Vector2.right * horizontal * moveForce);
		}

		//slow the player down horizontally if travelling too fast
		if (Mathf.Abs (rigidBody.velocity.x) > maxSpeed) {
			rigidBody.velocity = new Vector2 (Mathf.Sign (rigidBody.velocity.x) * maxSpeed, rigidBody.velocity.y);
		}

		//slow the player down if no input, or input is other direction
		if (horizontal * rigidBody.velocity.x <= 0) {
			rigidBody.velocity = new Vector2 (rigidBody.velocity.x/stopDivisor, rigidBody.velocity.y);
		}

		//slow the fall speed
		if (rigidBody.velocity.y < maxFallSpeed) {
			rigidBody.velocity = new Vector2 (rigidBody.velocity.x, Mathf.Sign (rigidBody.velocity.y) * -maxFallSpeed);
		}

		//jump up
		if (jump) {
			if (!grounded) {
				rigidBody.velocity = new Vector2 (rigidBody.velocity.x, 0f);
				airJumpCount++;
			}
			rigidBody.AddForce (new Vector2 (0f, jumpForce));
			jump = false;
		}

		//flip the sprite to face the right way
		if (rigidBody.velocity.x > 0.001f || rigidBody.velocity.x < -0.001f) {
			lastXSpeed = rigidBody.velocity.x;
		}
		Vector3 scale = transform.localScale;
		scale.x = lastXSpeed >= 0 ? Mathf.Abs(scale.x) : -Mathf.Abs(scale.x);
		transform.localScale = scale;
	}

	void OnTriggerExit2D(Collider2D collider) {
		Killbox killbox = collider.gameObject.GetComponent<Killbox> ();
		if (killbox != null) {
			Respawn ();
		}
	}

	void Respawn() {
		rigidBody.velocity = Vector2.zero;
		rigidBody.position = new Vector2 (spawnPointX, spawnPointY);
	}

	void OnDrawGizmos() {
		Gizmos.color = Color.red;
		Gizmos.DrawLine (transform.position, transform.position + new Vector3 (hitboxLeft, hitboxBottom - 0.01f, 0));
		Gizmos.DrawLine (transform.position, transform.position + new Vector3(hitboxRight, hitboxBottom - 0.01f, 0));
	}
}