public Particle Create(float creationTime)
{
var p = new Particle(creationTime);
p.LifeTime = 10f;
Func<float> Rnd01 = () => (float)random.NextDouble();
Func<float> RndCoord = () => (Rnd01() - 0.5f) * 2.0f;
//around emitter position
p.Position = emitterPos + new Vector3(RndCoord(), RndCoord(), RndCoord()) * .1f;
//speed between [.002, .004]
p.Velocity = Vector3.Zero;
//gravity
p.Acceleration = new Vector3(0, -.4f, 0);
return p;
}
public Particle Create(float creationTime)
{
var p = new Particle(creationTime);
p.LifeTime = 10f;
Func<float> Rnd01 = () => (float)random.NextDouble();
Func<float> RndCoord = () => (Rnd01() - 0.5f) * 2.0f;
//start at emitter position
p.Position = Emitter;
//slightly different upward vectors
var direction = new Vector3(0.3f * RndCoord(), 1, 0.3f * RndCoord());
//speed between [.2, .4]
p.Velocity = (.2f + .2f * Rnd01()) * direction;
p.Acceleration = Wind;
return p;
}
private void InitParticles()
{
var rnd = new Random(12);
Func<float> Rnd01 = () => (float)rnd.NextDouble();
Func<float> RndCoord = () => (Rnd01() - 0.5f) * 2.0f;
Func<float> RndSpeed = () => (Rnd01() - 0.5f) * 0.01f;
bufferParticles = new BufferObject(BufferTarget.ShaderStorageBuffer);
var data = new Particle[particelCount];
for (int i = 0; i < particelCount; ++i)
{
data[i].position = new Vector2(RndCoord(), RndCoord());
data[i].velocity = new Vector2(RndSpeed(), RndSpeed());
}
bufferParticles.Set(data, BufferUsageHint.StaticCopy);
}
private void OnAfterParticleUpdate(Particle particle)
{
Func<float> Rnd01 = () => (float)random.NextDouble();
Func<float> RndCoord = () => (Rnd01() - 0.5f) * 2.0f;
if (particle.Position.Y < 0)
{
//slightly different upward vectors
var direction = new Vector3(RndCoord(), Rnd01(), RndCoord()).Normalized();
var speed = particle.Velocity.Length;
particle.Velocity = direction * speed * 0.7f;
}
}