public ParticleEmitter(ParticleData data)
{
if (r == null) r = new Random();
particleData = data;
particles = new List<Particle>();
ngon = new nGonBuilder(Color.White);
}
public static ParticleEmitter CreateStream(Color c, float time, float speed, float scaleMax)
{
ParticleData data = new ParticleData();
data.Blend = ColorBlendMode.TimeLerp;
data.Bounce = BounceMode.None;
data.Colors = new Color[] { Color.White, c, Color.Black };
data.MaxSides = 2;
data.MinSides = 2;
data.MaxSpeed = speed + 0.5f;
data.MinSpeed = speed;
data.MaxTime = time + 1;
data.MinTime = time;
data.Rotation = RotationMode.Direction;
data.RotationMult = 1;
data.Scale = ScaleMode.Time;
data.ScaleMax = scaleMax;
data.ScaleMin = 1;
ParticleEmitter emitter = new ParticleEmitter(data);
return emitter;
}
private Particle CreateParticle(ParticleData data, Vector2 pos, float? dir = null)
{
Particle p = new Particle();
p.color = particleData.Colors[0];
p.lifetime = 0;
p.position = pos;
if (dir.HasValue)
p.direction = new Vector2((float)Math.Cos(dir.Value), (float)Math.Sin(dir.Value));
else
p.direction = new Vector2((float)r.NextDouble() - 0.5f, (float)r.NextDouble() - 0.5f);
p.direction.Normalize();
p.velocity = ((float)r.NextDouble() * (data.MaxSpeed - data.MinSpeed)) + data.MinSpeed;
p.lifespan = ((float)r.NextDouble() * (data.MaxTime - data.MinTime)) + data.MinTime;
switch(data.Scale)
{
case ScaleMode.Pick:
if (r.NextDouble() > 0.5)
p.scale = data.ScaleMin;
else p.scale = data.ScaleMax;
break;
case ScaleMode.Random:
p.scale = ((float)r.NextDouble() * (data.ScaleMax - data.ScaleMin)) + data.ScaleMin;
break;
case ScaleMode.Time:
p.scale = data.ScaleMin;
break;
case ScaleMode.Velocity:
p.scale = ((p.velocity - data.MinSpeed) / (data.MaxSpeed - data.MinSpeed)) * (data.ScaleMax - data.ScaleMin) + data.ScaleMin;
break;
}
p.sides = r.Next(data.MinSides, data.MaxSides + 1);
p.rotation = (float)Math.Atan2(p.direction.Y, p.direction.X);
return p;
}
public float velocity; //velocity of the particle
#endregion Fields
#region Methods
public bool Update(ParticleData data)
{
lifetime += Time.Delta;
if (lifetime > lifespan)
return false;
position += direction * velocity * Time.Delta;
if (data.Bounce == BounceMode.Both || data.Bounce == BounceMode.Vertical)
{
if (position.Y > Screen.Y && direction.Y > 0 ||
position.Y < -Screen.Y && direction.Y < 0)
{
direction.Y *= -1;
rotation = (float)Math.Atan2(direction.Y, direction.X);
}
}
if (data.Bounce == BounceMode.Both || data.Bounce == BounceMode.Horizontal)
{
if (position.X > Screen.X && direction.X > 0 ||
position.X < -Screen.X && direction.X < 0)
{
direction.X *= -1;
rotation = (float)Math.Atan2(direction.Y, direction.X);
}
}
switch (data.Scale)
{
case ScaleMode.Time:
scale = ((lifetime / lifespan) * (data.ScaleMax - data.ScaleMin)) + data.ScaleMin;
break;
case ScaleMode.Velocity:
scale = ((velocity - data.MinSpeed) / (data.MaxSpeed - data.MinSpeed)) * (data.ScaleMax - data.ScaleMin) + data.ScaleMin;
break;
}
int id = 0;
float step = lifespan / (data.Colors.Length - 1);
while ((id + 1) * step < lifetime) id++;
color = Color.Lerp(data.Colors[id], data.Colors[id + 1], (lifetime - (id * step)) / step);
return true;
}
