为了达到这种视差卷轴的效果，可以让背景层以不同的速度进行移动，越远的层，移动地越慢。如果操作得当，这可以造成深度的错觉，这将很酷，又是可以容易做到的效果。在这里存在两个滚动：
接下来，实现无限背景。当左侧的背景对象远离了摄像机的左边缘，那么就将它移到右侧去，一直这样无限循环，如下图所示：
要做到检查的对象渲染器是否在摄像机的可见范围内，需要一个类扩展。创建一个C#文件，命名为" RendererExtensions.cs"，代码如下：
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using UnityEngine;
public static class RendererExtensions
{
public static bool IsVisibleFrom( this Renderer renderer, Camera camera)
{
Plane[] planes = GeometryUtility.CalculateFrustumPlanes(camera);
return GeometryUtility.TestPlanesAABB(planes, renderer.bounds);
}
}
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修改" ScrollingScript"脚本文件，为如下：
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using System.Collections.Generic;
using System.Linq;
using UnityEngine;
/// <summary>
/// Parallax scrolling script that should be assigned to a layer
/// </summary>
public class ScrollingScript : MonoBehaviour
{
/// <summary>
/// Scrolling speed
/// </summary>
public Vector2 speed = new Vector2( 10, 10);
/// <summary>
/// Moving direction
/// </summary>
public Vector2 direction = new Vector2(- 1, 0);
/// <summary>
/// Movement should be applied to camera
/// </summary>
public bool isLinkedToCamera = false;
/// <summary>
/// 1 - Background is infinite
/// </summary>
public bool isLooping = false;
/// <summary>
/// 2 - List of children with a renderer.
/// </summary>
private List<Transform> backgroundPart;
// 3 - Get all the children
void Start()
{
// For infinite background only
if (isLooping)
{
// Get all the children of the layer with a renderer
backgroundPart = new List<Transform>();
for ( int i = 0; i < transform.childCount; i++)
{
Transform child = transform.GetChild(i);
// Add only the visible children
if (child.renderer != null)
{
backgroundPart.Add(child);
}
}
// Sort by position.
// Note: Get the children from left to right.
// We would need to add a few conditions to handle
// all the possible scrolling directions.
backgroundPart = backgroundPart.OrderBy(
t => t.position.x
).ToList();
}
}
void Update()
{
// Movement
Vector3 movement = new Vector3(
speed.x * direction.x,
speed.y * direction.y,
0);
movement *= Time.deltaTime;
transform.Translate(movement);
// Move the camera
if (isLinkedToCamera)
{
Camera.main.transform.Translate(movement);
}
// 4 - Loop
if (isLooping)
{
// Get the first object.
// The list is ordered from left (x position) to right.
Transform firstChild = backgroundPart.FirstOrDefault();
if (firstChild != null)
{
// Check if the child is already (partly) before the camera.
// We test the position first because the IsVisibleFrom
// method is a bit heavier to execute.
if (firstChild.position.x < Camera.main.transform.position.x)
{
// If the child is already on the left of the camera,
// we test if it's completely outside and needs to be
// recycled.
if (firstChild.renderer.IsVisibleFrom(Camera.main) == false)
{
// Get the last child position.
Transform lastChild = backgroundPart.LastOrDefault();
Vector3 lastPosition = lastChild.transform.position;
Vector3 lastSize = (lastChild.renderer.bounds.max - lastChild.renderer.bounds.min);
// Set the position of the recyled one to be AFTER
// the last child.
// Note: Only work for horizontal scrolling currently.
firstChild.position = new Vector3(lastPosition.x + lastSize.x, firstChild.position.y, firstChild.position.z);
// Set the recycled child to the last position
// of the backgroundPart list.
backgroundPart.Remove(firstChild);
backgroundPart.Add(firstChild);
}
}
}
}
}
}
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在
Start方法里，使用了LINQ将它们按X轴进行排序。将"
0 - Background"对象里的"
ScrollingScript"组件的"
Is Looping"属性勾选，现在运行，就可以看到视差卷轴的效果，如下图所示：
接下来，修改敌人脚本，让敌人静止不动，且无敌，直到摄像机看到它们。另外，当它们移出屏幕时，则立刻移除它们。修改" EnemyScript"脚本，代码为如下：
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u
sing UnityEngine;
/// <summary>
/// Enemy generic behavior
/// </summary>
public class EnemyScript : MonoBehaviour
{
private bool hasSpawn;
private MoveScript moveScript;
private WeaponScript[] weapons;
void Awake()
{
// Retrieve the weapon only once
weapons = GetComponentsInChildren<WeaponScript>();
// Retrieve scripts to disable when not spawn
moveScript = GetComponent<MoveScript>();
}
// 1 - Disable everything
void Start()
{
hasSpawn = false;
// Disable everything
// -- collider
collider2D.enabled = false;
// -- Moving
moveScript.enabled = false;
// -- Shooting
foreach (WeaponScript weapon in weapons)
{
weapon.enabled = false;
}
}
void Update()
{
// 2 - Check if the enemy has spawned.
if (hasSpawn == false)
{
if (renderer.IsVisibleFrom(Camera.main))
{
Spawn();
}
}
else
{
// Auto-fire
foreach (WeaponScript weapon in weapons)
{
if (weapon != null && weapon.enabled && weapon.CanAttack)
{
weapon.Attack( true);
}
}
// 4 - Out of the camera ? Destroy the game object.
if (renderer.IsVisibleFrom(Camera.main) == false)
{
Destroy(gameObject);
}
}
}
// 3 - Activate itself.
private void Spawn()
{
hasSpawn = true;
// Enable everything
// -- Collider
collider2D.enabled = true;
// -- Moving
moveScript.enabled = true;
// -- Shooting
foreach (WeaponScript weapon in weapons)
{
weapon.enabled = true;
}
}
}
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现在运行的话，会发现主角永远看不到敌人，因为敌人也跟随者层移动了。解决方法，只需将" 3 - Foreground"层上的" ScrollingScript"脚本移除掉即可。在游戏过程中，可以发现主角并不是限制在摄像机区域内的，可以随意离开摄像机，现在来修复这个问题。打开" PlayerScript"脚本，在 Update方法里面添加如下代码：
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void Update()
{
// ...
// 6 - Make sure we are not outside the camera bounds
var dist = (transform.position - Camera.main.transform.position).z;
var leftBorder = Camera.main.ViewportToWorldPoint(
new Vector3( 0, 0, dist)
).x;
var rightBorder = Camera.main.ViewportToWorldPoint(
new Vector3( 1, 0, dist)
).x;
var topBorder = Camera.main.ViewportToWorldPoint(
new Vector3( 0, 0, dist)
).y;
var bottomBorder = Camera.main.ViewportToWorldPoint(
new Vector3( 0, 1, dist)
).y;
transform.position = new Vector3(
Mathf.Clamp(transform.position.x, leftBorder, rightBorder),
Mathf.Clamp(transform.position.y, topBorder, bottomBorder),
transform.position.z
);
// End of the update method
}
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2.粒子效果
制作一个爆炸的粒子，用于敌人或者主角被摧毁时进行显示。创建一个"
Particle System"，导入烟图片到 "
Textures "文件夹，改变其"
Texture Type"为" Texture"，并且勾选"
Alpha Is Transparent"属性，附加这个纹理到粒子上，将其拖动到粒子对象上，更改其Shader为"
Particles "→" Alpha Blended"，接着更改一些属性，如下所示：
| Category |
Parameter name |
Value |
| General |
Duration |
1 |
| General |
Max Particles |
15 |
| General |
Start Lifetime |
1 |
| General |
Start Color |
Gray |
| General |
Start Speed |
3 |
| General |
Start Size |
2 |
| Emission |
Bursts |
0 : 15 |
| Shape |
Shape |
Sphere |
| Color Over Lifetime |
Color |
See below (N°1) |
| Size Over Lifetime |
Size |
See below (N°2) |
其中
Color Over Lifetime要设置成在结束时，有个淡出的效果，如下图所示：
Size Over Lifetime选择一个递减曲线，如下图所示：
当调整完成后，取消勾选"
Looping"，现在粒子效果为如下：
保存成预制，命名为"
SmokeEffect"，放在"
Prefabs/Particles"文件夹下。现在创建另一个粒子，火焰效果，使用默认材质即可。其他设置如下：
| Category |
Parameter name |
Value |
| General |
Looping |
false |
| General |
Duration |
1 |
| General |
Max Particles |
10 |
| General |
Start Lifetime |
1 |
| General |
Start Speed |
0.5 |
| General |
Start Size |
2 |
| Emission |
Bursts |
0 : 10 |
| Shape |
Shape |
Box |
| Color Over Lifetime |
Color |
See below (N°1) |
其中
Color Over Lifetime要设置成有一个黄色到橙色的渐变，最后淡出，如下图所示：
粒子效果为：
保存成预制，命名为" FireEffect"。创建一个脚本，命名为" SpecialEffectsHelper"，代码如下：
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using UnityEngine;
/// <summary>
/// Creating instance of particles from code with no effort
/// </summary>
public class SpecialEffectsHelper : MonoBehaviour
{
/// <summary>
/// Singleton
/// </summary>
public static SpecialEffectsHelper Instance;
public ParticleSystem smokeEffect;
public ParticleSystem fireEffect;
void Awake()
{
// Register the singleton
if (Instance != null)
{
Debug.LogError( "Multiple instances of SpecialEffectsHelper!");
}
Instance = this;
}
/// <summary>
/// Create an explosion at the given location
/// </summary>
/// <param name="position"></param>
public void Explosion(Vector3 position)
{
// Smoke on the water
instantiate(smokeEffect, position);
// Tu tu tu, tu tu tudu
// Fire in the sky
instantiate(fireEffect, position);
}
/// <summary>
/// Instantiate a Particle system from prefab
/// </summary>
/// <param name="prefab"></param>
/// <returns></returns>
private ParticleSystem instantiate(ParticleSystem prefab, Vector3 position)
{
ParticleSystem newParticleSystem = Instantiate(
prefab,
position,
Quaternion.identity
) as ParticleSystem;
// Make sure it will be destroyed
Destroy(
newParticleSystem.gameObject,
newParticleSystem.startLifetime
);
return newParticleSystem;
}
}
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这里创建了一个单例，可以让任何地方都可以产生烟和火焰的粒子。将这个脚本附加到"
Scripts"对象，设置其属性"
Smoke Effect"和"
Fire Effect"为对应的预制体。现在是时候调用这个脚本了，打开"
HealthScript"脚本文件，在
OnTriggerEnter方法里面，更新成如下代码：
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public Damage( int damageCount)
{
// ...
if (hp <= 0)
{
// 'Splosion!
SpecialEffectsHelper.Instance.Explosion(transform.position);
// Dead!
Destroy(gameObject);
}
// ...
}
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3.音乐和音效
现在来添加一些声音。将声音资源放入" Sounds"文件夹，取消勾选每一个声音的" 3D sound"属性，因为这是2D游戏。准备播放背景音乐，创建一个游戏对象，命名为" Music"，其 Position为(0, 0, 0)，将背景音乐拖到这个对象上，然后勾选" Mute"属性。因为音效总是在一定的时机进行播放，所以创建一个脚本文件，命名为" SoundEffectsHelper"，代码如下：
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using UnityEngine;
using System.Collections;
/// <summary>
/// Creating instance of sounds from code with no effort
/// </summary>
public class SoundEffectsHelper : MonoBehaviour
{
/// <summary>
/// Singleton
/// </summary>
public static SoundEffectsHelper Instance;
public AudioClip explosionSound;
public AudioClip playerShotSound;
public AudioClip enemyShotSound;
void Awake()
{
// Register the singleton
if (Instance != null)
{
Debug.LogError( "Multiple instances of SoundEffectsHelper!");
}
Instance = this;
}
public void MakeExplosionSound()
{
MakeSound(explosionSound);
}
public void MakePlayerShotSound()
{
MakeSound(playerShotSound);
}
public void MakeEnemyShotSound()
{
MakeSound(enemyShotSound);
}
/// <summary>
/// Play a given sound
/// </summary>
/// <param name="originalClip"></param>
private void MakeSound(AudioClip originalClip)
{
// As it is not 3D audio clip, position doesn't matter.
AudioSource.PlayClipAtPoint(originalClip, transform.position);
}
}
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将此脚本附加到"
Scripts"对象上，然后设置其属性值，如下图所示：
接着，在" HealthScript"脚本文件里，播放粒子效果后面，添加代码：
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SoundEffectsHelper.Instance.MakeExplosionSound();
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在" PlayerScript"脚本文件里，代码 weapon.Attack(false);后面，添加代码：
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SoundEffectsHelper.Instance.MakePlayerShotSound();
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在" EnemyScript"脚本文件里，代码 weapon.Attack(false);后面，添加代码：
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SoundEffectsHelper.Instance.MakeEnemyShotSound();
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现在运行，就可以听到声音了。
4.菜单
创建简单的菜单，以便游戏可以重新开始。导入背景图片和LOGO图片到 " Textures "文件夹的子文件夹" Menu"。创建一个新的场景，命名为"Menu"。添加背景 Sprite对象，其Position为 (0, 0, 1)，Size为 (2, 2, 1)。添加LOGO的Sprite对象，其Position为 (0, 2, 0)，Size为 (0.75, 0.75, 1)。添加一个空对象，命名为"Scripts"，用来加载脚本。现在为这个启动画面，添加一个开始按钮。创建一个脚本文件，命名为" MenuScript"，代码如下：
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using UnityEngine;
/// <summary>
/// Title screen script
/// </summary>
public class MenuScript : MonoBehaviour
{
void OnGUI()
{
const int buttonWidth = 84;
const int buttonHeight = 60;
// Draw a button to start the game
if (
GUI.Button(
// Center in X, 2/3 of the height in Y
new Rect(
Screen.width / 2 - (buttonWidth / 2),
( 2 * Screen.height / 3) - (buttonHeight / 2),
buttonWidth,
buttonHeight
),
"Start!"
)
)
{
// On Click, load the first level.
// "Stage1" is the name of the first scene we created.
Application.LoadLevel( "Stage1");
}
}
}
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将此脚本附加到"
Scripts"对象上。现在运行，可以 看到如下效果：
但是，点击按钮会崩溃，因为没有将 Stage1场景添加进来。打开" File"→" Build Settings"，将场景" Menu"和" Stage1"拖动到上面的" Scenes In Build"里面。再次运行，就可以看到按钮正常切换场景了。当主角被摧毁时，需要可以重新开始游戏。创建一个脚本文件，命名为" GameOverScript"，代码如下：
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using UnityEngine;
/// <summary>
/// Start or quit the game
/// </summary>
public class GameOverScript : MonoBehaviour
{
void OnGUI()
{
const int buttonWidth = 120;
const int buttonHeight = 60;
if (
GUI.Button(
// Center in X, 1/3 of the height in Y
new Rect(
Screen.width / 2 - (buttonWidth / 2),
( 1 * Screen.height / 3) - (buttonHeight / 2),
buttonWidth,
buttonHeight
),
"Retry!"
)
)
{
// Reload the level
Application.LoadLevel( "Stage1");
}
if (
GUI.Button(
// Center in X, 2/3 of the height in Y
new Rect(
Screen.width / 2 - (buttonWidth / 2),
( 2 * Screen.height / 3) - (buttonHeight / 2),
buttonWidth,
buttonHeight
),
"Back to menu"
)
)
{
// Reload the level
Application.LoadLevel( "Menu");
}
}
}
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在主角死亡的时候，调用这个脚本。打开"
PlayerScript"文件，添加如下代码：
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oid OnDestroy()
{
// Game Over.
// Add the script to the parent because the current game
// object is likely going to be destroyed immediately.
transform.parent.gameObject.AddComponent<GameOverScript>();
}
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现在运行，当死亡时，就会出现按钮，如下图所示：
如文章存在错误之处，欢迎指出，以便改正。转载请注明出处。
