private void MakeButterflyFaceProperDirectionAndAdjustAnimationSpeed(DefaultAnimatedSpriteParticle cParticle)
{
// If the butterfly should face left
if (cParticle.Velocity.X < 0)
{
cParticle.FlipMode = SpriteEffects.FlipVertically;
}
// Else it should face right (the image default)
else
{
cParticle.FlipMode = SpriteEffects.None;
}
// Make the Butterfly animation go faster based on how fast it is moving upwards
float fNormalizedYVelocity = (cParticle.Velocity.Y + miButterflyMaxSpeed) / (miButterflyMaxSpeed * 2);
float fNewAnimationTime = MathHelper.Lerp(mfMinTimeBetweenAnimationImages, mfMaxTimeBetweenAnimationImages, fNormalizedYVelocity);
cParticle.Animation.CurrentAnimationsPictureRotationTime = fNewAnimationTime;
}
protected void ChangeDirectionRandomly(DefaultAnimatedSpriteParticle cParticle, float fElapsedTimeInSeconds)
{
// If this is the Mouse butterfly
if (ActiveParticles.Last != null && cParticle == ActiveParticles.Last.Value)
{
// Exit without doing anything
return;
}
// If we should pick a new Direction (happens randomly) (-1 is specified when initializing new particles)
float fClamped = MathHelper.Clamp(fElapsedTimeInSeconds, -1f, 0.01f);
if (RandomNumber.NextFloat() < fClamped || fElapsedTimeInSeconds < 0)
{
// Calculate a new Velocity direction
cParticle.Velocity = new Vector3(RandomNumber.Next(-miButterflyMaxSpeed, miButterflyMaxSpeed),
RandomNumber.Next(-miButterflyMaxSpeed, miButterflyMaxSpeed),
0);
// Calculate the new Direction the Butterfly should face
MakeButterflyFaceProperDirectionAndAdjustAnimationSpeed(cParticle);
}
}
public void InitializeParticleAnimatedButterfly(DefaultAnimatedSpriteParticle cParticle)
{
InitializeParticleUsingInitialProperties(cParticle);
cParticle.Animation.CopyFrom(mcButterflyAnimation);
// If this is the first Particle to be added
if (NumberOfActiveParticles == 0)
{
// Set the Particle to live forever
cParticle.Lifetime = -1.0f;
// Place the Particle in the middle of the screen to begin with
cParticle.Position = new Vector3(miScreenWidth / 2, miScreenHeight / 2, 0);
// Make sure it does not move on it's own
cParticle.Velocity = Vector3.Zero;
cParticle.Acceleration = Vector3.Zero;
cParticle.ExternalForce = Vector3.Zero;
// Set the Animation to play forever (since the particles die when the animation ends)
cParticle.Animation.CurrentAnimationsNumberOfTimesToPlay = 0;
}
else
{
// Set this new Particle to start from the same position in the Animation as the Mouse Butterfly current is
cParticle.Animation.CurrentAnimationsPictureRotationOrderIndex = ActiveParticles.Last.Value.Animation.CurrentAnimationsPictureRotationOrderIndex;
// Have this butterfly go in a random direction
ChangeDirectionRandomly(cParticle, -1);
}
}
//===========================================================
// Particle Update Functions
//===========================================================
protected void BounceOffScreenEdges(DefaultAnimatedSpriteParticle cParticle, float fElapsedTimeInSeconds)
{
int iLeft = (int)(cParticle.Position.X - (cParticle.Width / 4));
int iRight = (int)(cParticle.Position.X + (cParticle.Width / 4));
int iTop = (int)(cParticle.Position.Y - (cParticle.Height / 4));
int iBottom = (int)(cParticle.Position.Y + (cParticle.Height / 4));
// If the Particle is heading off the left or right side of the screen
if ((iLeft < 0 && cParticle.Velocity.X < 0) ||
(iRight > miScreenWidth && cParticle.Velocity.X > 0))
{
// Reverse it's horizontal direction
cParticle.Velocity.X *= -1;
}
// If the Particle is heading off the top or bottom of the screen
if ((iTop < 0 && cParticle.Velocity.Y < 0) ||
(iBottom > miScreenHeight && cParticle.Velocity.Y > 0))
{
// Reverse it's vertical direction
cParticle.Velocity.Y *= -1;
}
// Make sure the Butterfly is still orientated properly
MakeButterflyFaceProperDirectionAndAdjustAnimationSpeed(cParticle);
}
public void InitializeParticleAnimatedExplosion(DefaultAnimatedSpriteParticle cParticle)
{
InitializeParticleUsingInitialProperties(cParticle);
cParticle.Animation.CopyFrom(mcExplosionAnimation);
}
