private void DoAsteroidCreation()
{
Asteroid a = new Asteroid ();
int drawIndex = mRandom.Next (0, 4);
a.DrawY = mAsteroidMinY + (drawIndex * 63);
a.DrawX = (mCanvasWidth - mAsteroids[0].Width);
a.StartTime = DateTime.Now.Ticks / TimeSpan.TicksPerMillisecond;
asteroids.Add (a);
}
// Update asteroid state including position and laser hit status.
protected void UpdateAsteroids(object inputContext)
{
if (asteroids == null | asteroids.Count == 0)
{
return;
}
for (int i = (asteroids.Count - 1); i >= 0; i--)
{
Asteroid asteroid = asteroids[i];
// If the asteroid is within laser range but not already missed
// check if the key was pressed close enough to the beat to make a hit
if (asteroid.DrawX <= mAsteroidMoveLimitX + 20 && !asteroid.Missed)
{
// If the laser was fired on the beat destroy the asteroid
if (mLaserOn)
{
// Track hit streak for adjusting music
scores.HitStreak++;
scores.HitTotal++;
// Replace the asteroid with an explosion
Explosion ex = new Explosion();
ex.AnimationIndex = 0;
ex.DrawX = asteroid.DrawX;
ex.DrawY = asteroid.DrawY;
explosions.Add(ex);
mJet.SetMuteFlag(24, false, false);
asteroids.RemoveAt(i);
// This asteroid has been removed process the next one
continue;
}
else
{
// Sorry, timing was not good enough, mark the asteroid
// as missed so on next frame it cannot be hit even if it is still
// within range
asteroid.Missed = true;
scores.HitStreak = scores.HitStreak - 1;
if (scores.HitStreak < 0)
{
scores.HitStreak = 0;
}
}
}
// Update the asteroids position, even missed ones keep moving
asteroid.DrawX -= mPixelMoveX;
// Update asteroid animation frame
asteroid.AnimationIndex = (asteroid.AnimationIndex + ANIMATION_FRAMES_PER_BEAT)
% mAsteroids.Length;
// if we have scrolled off the screen
if (asteroid.DrawX < 0)
{
asteroids.RemoveAt(i);
}
}
}