向后运动抖动精神套件

Question

所以我在精灵套件中为角色实现了一些运动，向前运动工作正常、漂亮且流畅，但是当我应用相反的 （-） 力时，该部分用于向后移动，但它有效，但看起来仍然有一个小的向前力推动它，使其抖动，所以看起来很丑且不流畅，

这是我用于所有力的代码，包括重力和跳跃（以便更好地理解）

 - (void)update:(NSTimeInterval)delta
{
  CGPoint gravity = CGPointMake(0.0, -450.0);
  CGPoint gravityStep = CGPointMultiplyScalar(gravity, delta);

  //FORWARD MOVE
  CGPoint forwardMove = CGPointMake(800.0, 0.0);
  CGPoint forwardMoveStep = CGPointMultiplyScalar(forwardMove, delta);
  //BACKMOVE
  CGPoint BackwardsMove = CGPointMake(-800.0, 0.0);
  CGPoint BackMoveStep = CGPointMultiplyScalar(BackwardsMove, delta);
  self.velocity = CGPointAdd(self.velocity, gravityStep);
  self.velocity = CGPointMake(self.velocity.x * 0.9, self.velocity.y);
  CGPoint jumpForce = CGPointMake(0.0, 310.0);
  float jumpCutoff = 150.0;
  if (self.mightAsWellJump && self.onGround) {
    self.velocity = CGPointAdd(self.velocity, jumpForce);
    [self runAction:[SKAction playSoundFileNamed:@"jump.wav" waitForCompletion:NO]];
  } else if (!self.mightAsWellJump && self.velocity.y > jumpCutoff) {
    self.velocity = CGPointMake(self.velocity.x, jumpCutoff);
  }
  if (self.forwardMarch) {
    self.velocity = CGPointAdd(self.velocity, forwardMoveStep);
    CGPoint minMovement = CGPointMake(0.0, -450);
    CGPoint maxMovement = CGPointMake(120.0, 250.0);
    self.velocity = CGPointMake(Clamp(self.velocity.x, minMovement.x, maxMovement.x), Clamp(self.velocity.y, minMovement.y, maxMovement.y));
  }
  if (self.BackwardsMarch) {

    self.velocity = CGPointSubtract(self.velocity, BackMoveStep);
    //self.velocity = CGPointAdd(self.velocity, BackMoveStep);
    CGPoint minMovement = CGPointMake(0.0, -450);
    CGPoint maxMovement = CGPointMake(-120.0, 250.0);
    //self.velocity = CGPointMake(-16.0, self.velocity.y);
      self.velocity = CGPointMake(Clamp(self.velocity.x, minMovement.x, maxMovement.x), Clamp(self.velocity.y, minMovement.y, maxMovement.y));

  }
  //4
  CGPoint velocityStep = CGPointMultiplyScalar(self.velocity, delta);
  self.desiredPosition = CGPointAdd(self.position, velocityStep);
}

如果有人可以弄清楚正在发生的事情以及如何解决这个问题，那就太好了！

Answer 1

我的猜测是，当你应用向后速度时，仍然有向前速度，这会导致抖动。当您要应用向后速度时，首先将 self.velocity 设置为零。然后向后移动。

Answer 2

所以，我想通了，@Knight0fDragon走在正确的轨道上，

我修改了下面的代码。一切都在正常进行。

 if (self.velocity.x >0) {
  self.velocity = CGPointMake(self.velocity.x * 0.9, self.velocity.y);
  }
  else
  {
    self.velocity = CGPointMake(0.0, self.velocity.y);
    self.velocity = CGPointMake(self.velocity.x * 0.9, self.velocity.y);
  }