游戏开发中，主相机应该是最重要的GameObject之一，毕竟游戏呈现给玩家，就是通过它。
相机的使用，在不同的游戏中，有很大的不同。这里总结一下自己学到的一些相关知识。
固定位置-游戏过程中相机的Transform属性不改变。
- 调整好位置后就不要动了,一般使用正交相机，即Camera-Projection选择Orthographic。Unity Manual-Camera
适用：2D游戏。比如飞机大战，消消乐。 - 游戏开始后，相机追踪某一物体，然后固定不动。
游戏开始后，我们才能确定追踪物体的位置，先看代码：
using UnityEngine; public class CameraController : MonoBehaviour
{
public GameObject player;
private Vector3 offset;
void Start ()
{
offset = transform.position - player.transform.position;
}
void LateUpdate ()
{
transform.position = player.transform.position + offset;
}
}
适用：固定视角的3D游戏。
3D视角-围绕一个中心随意旋转
先看代码：
using UnityEngine; public class CameraContorller : MonoBehaviour
{
/// <summary>
/// 追踪目标
/// </summary>
public Transform target;
/// <summary>
/// 旋转速度
/// </summary>
public float xSpeed = , ySpeed = ;
/// <summary>
/// 缩放速度
/// </summary>
public float mSpeed = ;
/// <summary>
/// 最小/最大限制角度
/// </summary>
public float yMinLimit = -, yMaxLimit = ;
/// <summary>
/// 是否使用插值运算
/// </summary>
public bool needDamping = true;
/// <summary>
/// 速度
/// </summary>
public float damping = 5.0f; /// <summary>
/// 观察距离
/// </summary>
private float distance = ;
/// <summary>
/// 最小/最大观察距离
/// </summary>
private float minDistance = , maxDistance = ;
/// <summary>
/// 旋转角度
/// </summary>
private float x = 0.0f, y = 0.0f; void Start()
{
Vector3 angles = transform.eulerAngles;
x = angles.y;
y = angles.x;
//根据相机的初始位置初始化距离，最大距离，最小距离；
Vector3 offset = transform.position - target.position;
distance = offset.magnitude;
minDistance = distance / ;
maxDistance = distance * ;
} void LateUpdate()
{
if (target)
{
if (Input.GetMouseButton())//0-左键,1-右键,2-中键
{
x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f; y = ClampAngle(y, yMinLimit, yMaxLimit);
}
distance -= Input.GetAxis("Mouse ScrollWheel") * mSpeed;
distance = Mathf.Clamp(distance, minDistance, maxDistance); Quaternion rotation = Quaternion.Euler(y, x, 0.0f);
Vector3 disVector = new Vector3(0.0f, 0.0f, -distance);
Vector3 position = rotation * disVector + target.position;
if (needDamping)
{
transform.rotation = Quaternion.Lerp(transform.rotation, rotation, Time.deltaTime * damping);
Vector3 transformTemp = Vector3.Lerp(transform.position, position, Time.deltaTime * damping);
if (transformTemp.y <= )//如果相机位置在“水平面”以下，强制设置到水平面。
{
transform.position = new Vector3(transformTemp.x, , transformTemp.z);
}
else
{
transform.position = transformTemp;
}
}
else
{
transform.rotation = rotation;
if (position.y <= )//如果相机位置在“水平面”以下，强制设置到水平面。
{
transform.position = new Vector3(position.x, , position.z);
}
else
{
transform.position = position;
}
}
}
} static float ClampAngle(float angle, float min, float max)
{
if (angle < -)
angle += ;
if (angle > )
angle -= ;
return Mathf.Clamp(angle, min, max);
}
}
大部分3D游戏中，我这样理解：主角看作球心，球半径玩家可以自己改变，相机的位置就在“地面”以上的半球球体上。
上面这段代码基本做到了这个要求，并在相机到“地面”的时候有抬头看的效果。
代码有点问题，开始游戏后相机会跳动两次，暂时放到自己的问题清单中。
其他用法
官方教程Tanks tutorial 中有个不常见的用法。
不管两个Tank如何移动，相机通过前后缩放，大小缩放保证两个Tank肯定在相机视野内。
主要代码：（官方代码写得好啊）
private void Move ()
{
// Find the average position of the targets.
FindAveragePosition (); // Smoothly transition to that position.
transform.position = Vector3.SmoothDamp(transform.position, m_DesiredPosition, ref m_MoveVelocity, m_DampTime);
} private void FindAveragePosition ()
{
Vector3 averagePos = new Vector3 ();
int numTargets = ; // Go through all the targets and add their positions together.
for (int i = ; i < m_Targets.Length; i++)
{
// If the target isn't active, go on to the next one.
if (!m_Targets[i].gameObject.activeSelf)
continue; // Add to the average and increment the number of targets in the average.
averagePos += m_Targets[i].position;
numTargets++;
} // If there are targets divide the sum of the positions by the number of them to find the average.
if (numTargets > )
averagePos /= numTargets; // Keep the same y value.
averagePos.y = transform.position.y; // The desired position is the average position;
m_DesiredPosition = averagePos;
} private void Zoom ()
{
// Find the required size based on the desired position and smoothly transition to that size.
float requiredSize = FindRequiredSize();
m_Camera.orthographicSize = Mathf.SmoothDamp (m_Camera.orthographicSize, requiredSize, ref m_ZoomSpeed, m_DampTime);
} private float FindRequiredSize ()
{
// Find the position the camera rig is moving towards in its local space.
Vector3 desiredLocalPos = transform.InverseTransformPoint(m_DesiredPosition); // Start the camera's size calculation at zero.
float size = 0f; // Go through all the targets...
for (int i = ; i < m_Targets.Length; i++)
{
// ... and if they aren't active continue on to the next target.
if (!m_Targets[i].gameObject.activeSelf)
continue; // Otherwise, find the position of the target in the camera's local space.
Vector3 targetLocalPos = transform.InverseTransformPoint(m_Targets[i].position); // Find the position of the target from the desired position of the camera's local space.
Vector3 desiredPosToTarget = targetLocalPos - desiredLocalPos; // Choose the largest out of the current size and the distance of the tank 'up' or 'down' from the camera.
size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.y)); // Choose the largest out of the current size and the calculated size based on the tank being to the left or right of the camera.
size = Mathf.Max(size, Mathf.Abs(desiredPosToTarget.x) / m_Camera.aspect);
} // Add the edge buffer to the size.
size += m_ScreenEdgeBuffer; // Make sure the camera's size isn't below the minimum.
size = Mathf.Max (size, m_MinSize); return size;
}
暂时放下的内容
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