public BTracker(SpriteX sprite, ref float moveSpeed, float RotSpeed,
float RotSpeedInc)
{
currentTarget = sprite.GetPosition();
newTarget = sprite.GetPosition();
Speed = moveSpeed;
this.sprite = sprite;
IsTracking = false;
IsReached = false;
this.MaxRotSpeed = RotSpeed;
this.RotSpeed = RotSpeed;
this.RotSpeedInc = RotSpeedInc;
}
public BTracker(SpriteX sprite,ref float moveSpeed,float RotSpeed,
float RotSpeedInc)
{
currentTarget = sprite.GetPosition();
newTarget = sprite.GetPosition();
Speed = moveSpeed ;
this.sprite =sprite;
IsTracking = false;
IsReached = false;
this.MaxRotSpeed = RotSpeed;
this.RotSpeed = RotSpeed;
this.RotSpeedInc = RotSpeedInc;
}
void TrackNow(Vector2 newPos)
{
Vector2 nowPos = sprite.GetPosition();
if (Maths.VectorsEquals(nowPos, currentTarget, 10f))
{ //到目标位置 就停止
IsTracking = false;
IsReached = true;
}
Vector2 targetDir = currentTarget - nowPos;
Maths.Normalize(ref targetDir);
//用叉乘来确定两个向量的位置关系
float cross = -sprite.NowDirection.X * targetDir.Y -
-sprite.NowDirection.Y * targetDir.X;
//选择旋转方向
if (Maths.VectorsEquals(targetDir, sprite.NowDirection, 0.16f))
{
cross = 0;
RotSpeed = MaxRotSpeed;
}
else
{
#region 旋转……
if (cross >= 0)
{
RotSpeed = Maths.Abs(RotSpeed);
RotSpeed += RotSpeedInc;
}
if (cross < 0)
{
RotSpeed = -Maths.Abs(RotSpeed);
RotSpeed -= RotSpeedInc;
}
#endregion
sprite.Rotate(RotSpeed);
}
sprite.SetPosition(sprite.GetPosition() +
sprite.NowDirection * Speed);
}