我试图确定用户以何种方式在屏幕上以圆周运动旋转手指。我目前正在尝试使用叉积和z组件来确定用户的旋转方式。这产生的结果适用于的下半部分,而在旋转的上半部分则相反。
有人能说明我做错了什么吗?
if ( ( Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Moved && GameStateManager.CurrentGameState == GameState.Minigame) )
{
Vector3 touchPos = Vector3.zero;
if( Camera.mainCamera != null )
{
touchPos = Camera.mainCamera.ScreenToWorldPoint( new Vector3( Input.GetTouch(0).position.x, Input.GetTouch(0).position.y, Camera.mainCamera.nearClipPlane ));
}
if( prevTouchPos == Vector2.zero )
{
prevTouchPos = new Vector2( touchPos.x, touchPos.y );
return;
}
//need angle between last finger position and this finger position
Vector2 prevVec = new Vector2( prevTouchPos.x - transform.position.x, prevTouchPos.y - transform.position.y );
Vector2 currVec = new Vector2( touchPos.x - transform.position.x, touchPos.y - transform.position.y );
float ang = Vector2.Angle(prevVec, currVec);
Vector3 cross = Vector3.Cross( new Vector3(prevVec.x, prevVec.y, 0), new Vector3(currVec.x, currVec.y, 0));
Debug.Log(cross.normalized);
if (cross.z < 0)
{
Debug.Log("Prev Vec: " + prevVec);
Debug.Log("Curr Vec: " + currVec);
Debug.Log("ROTATE RIGHT");
transform.Rotate( 0, 0, ang);
}
else
{
Debug.Log("Prev Vec: " + prevVec);
Debug.Log("Curr Vec: " + currVec);
Debug.Log("ROTATE LEFT");
transform.Rotate( 0, 0, -ang);
}
//Debug.Log(ang);
//Debug.Log( "TouchPos: " + touchPos );
prevTouchPos = new Vector2( touchPos.x, touchPos.y);
}
我过去也做过类似的事情,看起来很接近,这是我使用的代码,它确定用户是否在一个或另一个方向上完成了完整的360。请注意,这是C++中的内容,但这个想法应该会有所帮助。
thumbDir.Cross( thumbCur, thumbPrev );
float z = clamp( thumbDir.z, -1.0f, 1.0f );
float theta = asin( z );
if ( z > 0.0f )
{
// clockwise
if ( fDegrees > 0.0f )
fDegrees = -theta; // Reset angle if changed
else
fDegrees -= theta;
}
else if ( z < 0.0f )
{
// counter-clockwise
if ( fDegrees < 0.0f )
fDegrees = -theta; //Reset angle if changed
else
fDegrees -= theta;
}