Unity 2D移动轨迹预测

Question

我需要帮助在移动设备上进行轨迹预测。

我可以在电脑上用鼠标做到这一点，但在手机上用触摸功能做不到。

我有一个我在开始时复制的点，当我拖动球时，我想计算我的轨迹。

触摸结束后，我将摧毁这些点。

正如我所说，我可以使用Input.GetMouseButton/Up/Down，但我不能使用触摸功能。

这是我的代码：

private void Update()
{
//if (Input.touchCount > 0)
//{

Touch touch = Input.GetTouch(0);
if (touch.phase == TouchPhase.Began)
{
startPosition = Input.GetTouch(0).position;

for (int i = 0; i < number; i++)
{
trajectoryDots[i] = Instantiate(trajectoryDot, gameObject.transform);
} 
}
if (Input.touchCount > 0)
{
for (int i = 0; i < number; i++)
{
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
}
if (touch.phase == TouchPhase.Ended)
{
for (int i = 0; i < number; i++)
{
Destroy(trajectoryDots[i]);
}
endPoisiton = Input.GetTouch(0).position;
force = startPosition - endPoisiton;
ballRigid.gravityScale = 1;
ballRigid.velocity = new Vector2(force.x * power, force.y * power);
}
//}
}
private Vector2 calculatePosition(float elapsedTime)
{
return new Vector2(endPoisiton.x, endPoisiton.y) +
new Vector2(force.x * power, force.y * power) * elapsedTime +
0.5f * Physics2D.gravity * elapsedTime * elapsedTime;

}

我用于鼠标输入的代码

if (Input.GetMouseButtonDown(0))
{ //click
startPos = gameObject.transform.position;
for (int i = 0; i < number; i++)
{
trajectoryDots[i] = Instantiate(trajectoryDot, gameObject.transform);
}
}
if (Input.GetMouseButton(0))
{ //drag
endPos = Camera.main.ScreenToWorldPoint(Input.mousePosition) + new Vector3(0, 0, 10);
gameObject.transform.position = endPos;
forceAtPlayer = endPos - startPos;
for (int i = 0; i < number; i++)
{
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
}
if (Input.GetMouseButtonUp(0))
{ //leave
rigidbody.gravityScale = 1;
rigidbody.velocity = new Vector2(-forceAtPlayer.x * forceFactor, -forceAtPlayer.y * forceFactor);
for (int i = 0; i < number; i++)
{
Destroy(trajectoryDots[i]);
}
}

所以，经过一些小的改变后，情况好多了，我离我想要的越来越近了，我想还是有一些小故障，因为触摸。移动了，所以当我用手指在显示器上只做一些小动作时，球就会在屏幕上跳起来这是代码

private void Update()
{
if (Input.touchCount > 0)
{
var touch = Input.GetTouch(0);
switch (touch.phase)
{
case TouchPhase.Began:
initPosition = gameObject.transform.position;
startPosition = cam.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
for (int i = 0; i < number; i++)
{
trajectoryDots[i] = Instantiate(trajectoryDot, gameObject.transform);
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
break;
case TouchPhase.Moved:
endPosition = Camera.main.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
gameObject.transform.position = initPosition;
force = startPosition - endPosition;
for (int i = 0; i < number; i++)
{
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
break;
case TouchPhase.Ended:
ballRigid.gravityScale = 1;
ballRigid.velocity = new Vector2(force.x * power, force.y * power);
for (int i = 0; i < number; i++)
{
Destroy(trajectoryDots[i]);
}
break;
}
}
}
private Vector2 calculatePosition(float elapsedTime)
{
return new Vector2(initPosition.x, initPosition.y) +
new Vector2(force.x * power, force.y * power) * elapsedTime +
0.5f * Physics2D.gravity * elapsedTime * elapsedTime;
}

好的，我有最后的搜索，它工作正常

private void Update()
{
if (Input.touchCount > 0)
{
var touch = Input.GetTouch(0);
switch (touch.phase)
{
case TouchPhase.Began:
initPosition = gameObject.transform.position;
startPosition = cam.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
for (int i = 0; i < number; i++)
{
trajectoryDots[i] = Instantiate(trajectoryDot, gameObject.transform);
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
break;
case TouchPhase.Ended:
ballRigid.gravityScale = 1;
ballRigid.velocity = new Vector2(force.x * power, force.y * power);
for (int i = 0; i < number; i++)
{
Destroy(trajectoryDots[i]);
}
break;
}
endPosition = Camera.main.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
gameObject.transform.position = initPosition;
force = startPosition - endPosition;
for (int i = 0; i < number; i++)
{
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
}
}
private Vector2 calculatePosition(float elapsedTime)
{
return new Vector2(initPosition.x, initPosition.y) +
new Vector2(force.x * power, force.y * power) * elapsedTime +
0.5f * Physics2D.gravity * elapsedTime * elapsedTime;
}

Answer 1

因此，只需将鼠标代码转换为触摸代码，它可能看起来像

if(Input.touchCount > 0)
{
var touch = Input.GetTouch(0);
switch(touch.phase)
{
case TouchPhase.Began:
// Note: to be more accurate you actually probably would 
// rather also here use ScreenToWorldPoint on the touch.position
// same way as later. Otherwise you might allways get a force even if touch wasn't moved at all
//startPos = transform.position;
startPos = Camera.main.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
for (int i = 0; i < number; i++)
{
trajectoryDots[i] = Instantiate(trajectoryDot, gameObject.transform);
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
break;
case TouchPhase.Moved:
// These were missing in your touch version
// You did it only in the end so there were no preview trajectory
// And note that also touch is in pixel screenspace so if you
// want to use world positions you need to convert them just the same as for mouse input!
endPos = Camera.main.ScreenToWorldPoint(touch.position) + new Vector3(0, 0, 10);
transform.position = endPos;
force = endPos - startPos;
for (int i = 0; i < number; i++)
{
trajectoryDots[i].transform.position = calculatePosition(i * 0.1f);
}
break;
case TouchPhase.Ended:
rigidbody.gravityScale = 1;
// Not sure why but in your mouse code you used a negative force here 
// but in this case your trajectory would have been wrong since there you didn't use negative values...
rigidbody.velocity = force * forceFactor;
for (int i = 0; i < number; i++)
{
Destroy(trajectoryDots[i]);
}
break;
}
}

顺便说一句，计算方法读起来更像

private Vector2 calculatePosition(float elapsedTime)
{  
return endPoisiton 
+ force * power * elapsedTime 
+ Physics2D.gravity * 0.5f * elapsedTime * elapsedTime;
}

---

注意：在智能手机上打字，但我希望这个想法能清楚