public void Render(float x, float y, float ox, float oy)
{
// modulate gain
_Gain += _Parent.NextRandomFloat(-0.05f, 0.05f);
_Gain = _Gain.Clamp(0, 1);
// calculate grains by distance
//int grains = int(sqrt((ox-x)*(ox-x)+(oy-y)*(oy-y)));
const int grains = 64;
// lay down grains of sand (transparent pixels)
float w = _Gain / (grains - 1);
for (int i = 0; i < grains; i++)
{
var cx = ox + (x - ox) * (float)Math.Sin(Math.Sin(i * w));
var cy = oy + (y - oy) * (float)Math.Sin(Math.Sin(i * w));
float a = 0.1f - (float)i / (grains * 10.0f);
a *= 10;
_Parent.DrawPoint(cx, cy, _Color.WithAlpha((int)(a * 256)));
}
}