public void Update(float frameTime)
{
Age += frameTime;
if (Age >= Lifetime)
{
Alive = false;
}
Velocity += Acceleration * frameTime;
RadialVelocity += RadialAcceleration * frameTime;
TangentialVelocity += TangentialAcceleration * frameTime;
//Calculate delta p due to radial velocity
var positionRelativeToEmitter = Position - EmitterPosition;
var deltaRadial = RadialVelocity * frameTime;
var deltaPosition = positionRelativeToEmitter * (deltaRadial / positionRelativeToEmitter.Length);
//Calculate delta p due to tangential velocity
var radius = positionRelativeToEmitter.Length;
if (radius > 0)
{
var theta = MathUtility.ATan(positionRelativeToEmitter.Y, positionRelativeToEmitter.X);
theta += TangentialVelocity * frameTime;
deltaPosition += new Vector2D(radius * MathUtility.Cos(theta), radius * MathUtility.Sin(theta))
- positionRelativeToEmitter;
}
//Calculate delta p due to Velocity
deltaPosition += Velocity * frameTime;
Position += deltaPosition;
Spin += SpinVelocity * frameTime;
Size += SizeDelta * frameTime;
Color += ColorDelta * frameTime;
}