public bool DetectCollision(GameStagePlay stage)
{
if (this.Status == SaucerStatus.Active)
{
Missile missile = stage.Missile;
if (missile.IsActive &&
missile.YCenter >= this.YCenter &&
missile.YCenter <= this.YCenter + 1 &&
missile.XCenter >= this.XCenter - 1 &&
missile.XCenter <= this.XCenter + 2)
{
//got it!
this.Status = SaucerStatus.StartExplosion;
missile.IsActive = false;
//decide score, then accumulate it
this.PromisedScore = 10 * (1 + stage.Context.Rnd.Next(9));
stage.Context.CurrentScore += this.PromisedScore;
return(true);
}
}
return(false);
}
public void Update(GameStagePlay stage)
{
switch (this.Status)
{
case SaucerStatus.Inactive:
double hash;
if ((hash = stage.Context.Rnd.NextDouble()) < Probability)
{
if (hash < Probability / 2)
{
//will flight from left to right
this.XCenter = -8;
this._xLimit = stage.ViewportRight + 4;
}
else
{
//will flight from right to left
this.XCenter = stage.ViewportRight + 4;
this._xLimit = -8;
}
this.Status = SaucerStatus.Active;
}
break;
case SaucerStatus.Active:
if (stage.Context.IsEvenClock)
{
if (this.XCenter < this._xLimit)
{
this.XCenter++;
}
else
{
this.XCenter--;
}
if (this.XCenter == this._xLimit)
{
//sauce gone off screen being not hit
this.Status = SaucerStatus.Inactive;
}
else
{
//play releated sound
stage.Context.PlaySound(stage.Context.SoundSaucer);
}
}
break;
case SaucerStatus.StartExplosion:
this.Status = SaucerStatus.ExplodeExpand;
this._explosionClock = ExplosionTime;
//play related sound
stage.Context.PlaySound(stage.Context.SoundShipDestroyed);
break;
case SaucerStatus.ExplodeExpand:
if (--this._explosionClock == 0)
{
this.Status = SaucerStatus.ExplodeMax;
this._explosionClock = ExplosionTime;
}
break;
case SaucerStatus.ExplodeMax:
if (--this._explosionClock == 0)
{
this.Status = SaucerStatus.ExplodeCollapse;
this._explosionClock = ExplosionTime;
}
break;
case SaucerStatus.ExplodeCollapse:
if (--this._explosionClock == 0)
{
this.Status = SaucerStatus.Inactive;
stage.ShowSaucerWorth();
}
break;
}
}
