使用Unity 2D制作简单的UFO游戏

发表于2017-04-29

这篇教程将教大家使用Unity 2D功能制作一个非常简单的UFO游戏，适合Unity初学者以及对Unity 2D不甚熟悉的开发者们。

第一步新建项目设置场景
首先下载项目所需的资源，或者在Asset Store中下载Unity官方的2D UFO Tutorial。

新建2D项目，在Assets文件夹下新建三个文件夹：Prefabs、Scripts、Scenes。将下载的资源导入项目，会看到Sprites文件夹。将Sprites文件夹下的Background和UFO图片拖拽至层级视图（Hierarchy），将UFO重命名为Player。如下：

依次点击菜单项Edit > Project Settings > Tags and Layers，新建三个Sorting Layer分别命名为Background、Pickups和Players，然后设置各Sprite的Sorting Layer。

将Player的Scale设为(0.75, 0.75, 0)，如下：

将Main Camera的Size设为16.5，背景颜色设为RGB(32, 32, 32)，如下：

将场景保存到新建的Scenes文件夹下，任意命名即可，本例中命名为Main。

第二步添加控制主角的脚本
首先为Player游戏对象添加Rigibody 2D组件。然后新建脚本CompletePlayerController
用于控制Player对象，脚本代码如下：

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using UnityEngine;
using System.Collections;
 
//Adding this allows us to access members of the UI namespace including Text.
using UnityEngine.UI;
 
public class CompletePlayerController : MonoBehaviour {
 
        public float speed;                                //Floating point variable to store the player's movement speed.
        public Text countText;                        //Store a reference to the UI Text component which will display the number of pickups collected.
        public Text winText;                        //Store a reference to the UI Text component which will display the 'You win' message.
 
        private Rigidbody2D rb2d;                //Store a reference to the Rigidbody2D component required to use 2D Physics.
        private int count;                                //Integer to store the number of pickups collected so far.
 
        // Use this for initialization
        void Start()
        {
                //Get and store a reference to the Rigidbody2D component so that we can access it.
                rb2d = GetComponent ();
 
                //Initialize count to zero.
                count = 0;
 
                //Initialze winText to a blank string since we haven't won yet at beginning.
                winText.text = "";
 
                //Call our SetCountText function which will update the text with the current value for count.
                SetCountText ();
        }
 
        //FixedUpdate is called at a fixed interval and is independent of frame rate. Put physics code here.
        void FixedUpdate()
        {
                //Store the current horizontal input in the float moveHorizontal.
                float moveHorizontal = Input.GetAxis ("Horizontal");
 
                //Store the current vertical input in the float moveVertical.
                float moveVertical = Input.GetAxis ("Vertical");
 
                //Use the two store floats to create a new Vector2 variable movement.
                Vector2 movement = new Vector2 (moveHorizontal, moveVertical);
 
                //Call the AddForce function of our Rigidbody2D rb2d supplying movement multiplied by speed to move our player.
                rb2d.AddForce (movement * speed);
        }
 
        //OnTriggerEnter2D is called whenever this object overlaps with a trigger collider.
        void OnTriggerEnter2D(Collider2D other) 
        {
                //Check the provided Collider2D parameter other to see if it is tagged "PickUp", if it is...
                if (other.gameObject.CompareTag ("PickUp")) 
                {
                        //... then set the other object we just collided with to inactive.
                        other.gameObject.SetActive(false);
                         
                        //Add one to the current value of our count variable.
                        count = count + 1;
                         
                        //Update the currently displayed count by calling the SetCountText function.
                        SetCountText ();
                }
                 
 
        }
 
        //This function updates the text displaying the number of objects we've collected and displays our victory message if we've collected all of them.
        void SetCountText()
        {
                //Set the text property of our our countText object to "Count: " followed by the number stored in our count variable.
                countText.text = "Count: " + count.ToString ();
 
                //Check if we've collected all 12 pickups. If we have...
                if (count >= 12)
                        //... then set the text property of our winText object to "You win!"
                        winText.text = "You win!";
        }
}

依次点击Edit > Project Settings > Input设置控制键，如下：

将Player对象的Rigibody 2D组件的Gravity Scale属性设为0以防止Player向下坠落，并将PlayerController脚本的Speed属性设为10。

第三步添加碰撞
为Player添加Circle Collider 2D组件并将Radius属性设为2.15，如下：

接下来为背景添加碰撞体，让玩家不要跑出墙壁。为背景边框添加4个Box Collider 2D组件，各组件属性设置如下：

第四步让摄像机跟随主角
新建脚本CompleteCameraController绑定到Main Camera上，用于控制相机跟随主角移动。脚本代码如下：

[C#] 纯文本查看复制代码

using UnityEngine;
using System.Collections;
 
public class CompleteCameraController : MonoBehaviour {
 
        public GameObject player;                //Public variable to store a reference to the player game object
 
 
        private Vector3 offset;                        //Private variable to store the offset distance between the player and camera
 
        // Use this for initialization
        void Start () 
        {
                //Calculate and store the offset value by getting the distance between the player's position and camera's position.
                offset = transform.position - player.transform.position;
        }
         
        // LateUpdate is called after Update each frame
        void LateUpdate () 
        {
                // Set the position of the camera's transform to be the same as the player's, but offset by the calculated offset distance.
                transform.position = player.transform.position + offset;
        }
}

将Player游戏对象赋给CameraController脚本的player字段。

第五步设置宝石
将Sprites文件夹下的Pickup图片拖拽至层级视图，将其Sorting Layer设为Pickup并添加Circle Collider 2D组件。然后新建脚本CompleteRotator用于旋转宝石，脚本代码如下：

[C#] 纯文本查看复制代码

using UnityEngine;
using System.Collections;
 
public class CompleteRotator : MonoBehaviour {
 
        //Update is called every frame
        void Update () 
        {
                //Rotate thet transform of the game object this is attached to by 45 degrees, taking into account the time elapsed since last frame.
                transform.Rotate (new Vector3 (0, 0, 45) * Time.deltaTime);
        }
}

将该游戏对象拖拽至项目视图（Project）的Prefabs文件夹下存为预设体，在层级视图复制出11个宝石对象。然后在层级视图新建GameObject命名为Pickups，并将这12个对象均拖至Pickups下，分别设置合适的位置，如下图：

将Pickup预设体的Tag设为PickUp，并将所有Pickup对象的Circle Collider 2D组件的isTrigger属性勾选上：

第六步添加UI
右键点击层级视图，在弹出菜单中选择UI > Text新建文本，层级视图中除了Text外还会添加Canvas和EventSystem组件。将新建的Text命名为CountText，在检视面板中打开Rect Transform的锚点设置面板后按下Shift＋Alt／Option键点选左上角，让Text自动吸附到界面左上角并选择合适的文本颜色，如下图：