private void FixedUpdate()
{
//注：Time.deltaTime在FixUpdate()内是固定时间，取决于物理系统设置
if (!m_Started)
{
return;
}
//no need to update we have a single node in the path
if (m_Current == m_Next)
{
return;
}
if (m_WaitTime > 0)
{
m_WaitTime -= Time.deltaTime;
return;
}
float distanceToGo = speed * Time.deltaTime;
//当需要移动的距离大于0
while (distanceToGo > 0)
{
Vector2 direction = m_WorldNode[m_Next] - transform.position;
float dist = distanceToGo;
//当 离下一个节点的距离 小于 将要移动的位移时，即继续执行会超出目标点时
if (direction.sqrMagnitude < dist * dist)
{ //we have to go farther than our current goal point, so we set the distance to the remaining distance
//then we change the current & next indexes
dist = direction.magnitude;
m_Current = m_Next;
m_WaitTime = waitTimes[m_Current];
if (m_Dir > 0)
{
m_Next += 1;
if (m_Next >= m_WorldNode.Length)
{ //we reach the end
switch (platformType)
{
case MovingPlatformType.BACK_FORTH:
m_Next = m_WorldNode.Length - 2;
m_Dir = -1;
break;
case MovingPlatformType.LOOP:
m_Next = 0;
break;
case MovingPlatformType.ONCE:
m_Next -= 1;
StopMoving();
break;
}
}
}
else
{
m_Next -= 1;
if (m_Next < 0)
{ //reached the beginning again
switch (platformType)
{
case MovingPlatformType.BACK_FORTH:
m_Next = 1;
m_Dir = 1;
break;
case MovingPlatformType.LOOP:
m_Next = m_WorldNode.Length - 1;
break;
case MovingPlatformType.ONCE:
m_Next += 1;
StopMoving();
break;
}
}
}
}
//移动的距离+方向
m_Velocity = direction.normalized * dist;
//transform.position += direction.normalized * dist;
m_Rigidbody2D.MovePosition(m_Rigidbody2D.position + m_Velocity);
platformCatcher.MoveCaughtObjects(m_Velocity);
//We remove the distance we moved. That way if we didn't had enough distance to the next goal, we will do a new loop to finish
//the remaining distance we have to cover this frame toward the new goal
//这里利用浮点数减法的结果判断是否大于0来执行while循环，有待商榷
//Debug.Log(distanceToGo + "-" + dist + "=" + (distanceToGo - dist));
distanceToGo -= dist;
// we have some wait time set, that mean we reach a point where we have to wait. So no need to continue to move the platform, early exit.
//跳出，执行等待
if (m_WaitTime > 0.001f)
{
break;
}
}
}
private void FixedUpdate()
{
if (!m_Started)
{
return;
}
//no need to update we have a single node in the path
if (m_Current == m_Next)
{
return;
}
if (m_WaitTime > 0)
{
m_WaitTime -= Time.deltaTime;
return;
}
var distanceToGo = speed * Time.deltaTime;
while (distanceToGo > 0)
{
Vector2 direction = m_WorldNode[m_Next] - transform.position;
var dist = distanceToGo;
if (direction.sqrMagnitude < dist * dist)
{
//we have to go farther than our current goal point, so we set the distance to the remaining distance
//then we change the current & next indexes
dist = direction.magnitude;
m_Current = m_Next;
m_WaitTime = waitTimes[m_Current];
if (m_Dir > 0)
{
m_Next += 1;
if (m_Next >= m_WorldNode.Length)
{
switch (platformType)
{
case MovingPlatformType.BACK_FORTH:
m_Next = m_WorldNode.Length - 2;
m_Dir = -1;
break;
case MovingPlatformType.LOOP:
m_Next = 0;
break;
case MovingPlatformType.ONCE:
m_Next -= 1;
StopMoving();
break;
}
}
}
else
{
m_Next -= 1;
if (m_Next < 0)
{
switch (platformType)
{
case MovingPlatformType.BACK_FORTH:
m_Next = 1;
m_Dir = 1;
break;
case MovingPlatformType.LOOP:
m_Next = m_WorldNode.Length - 1;
break;
case MovingPlatformType.ONCE:
m_Next += 1;
StopMoving();
break;
}
}
}
}
m_Velocity = direction.normalized * dist;
//transform.position += direction.normalized * dist;
m_Rigidbody2D.MovePosition(m_Rigidbody2D.position + m_Velocity);
platformCatcher.MoveCaughtObjects(m_Velocity);
//We remove the distance we moved. That way if we didn't had enough distance to the next goal, we will do a new loop to finish
//the remaining distance we have to cover this frame toward the new goal
distanceToGo -= dist;
// we have some wait time set, that mean we reach a point where we have to wait. So no need to continue to move the platform, early exit.
if (m_WaitTime > 0.001f)
{
break;
}
}
}