bezier line

Ermol

After some time I come back to Particles. The decision was not difficult and will be possible interesting to someone. We create function which under the formula of cubic Bezier curve counts a point finding:

Code:

function TMainForm.Points(P0, P1, P2, P3: TPoint;
  Count, Index: Integer): TPoint;
var
  T, C0, C1, C2, C3: Extended;
begin
  T := Index / Count;
  C3 := T * T * T;
  C0 := C3 * -1 + T * T * 3 + T * -3 + 1;
  C1 := C3 * 3 + T * T * -6 + T * 3;
  C2 := C3 * -3 + T * T * 3;
  Result.X := Trunc(C0 * P0.X + C1 * P1.X + C2 * P2.X + C3 * P3.X);
  Result.Y := Trunc(C0 * P0.Y + C1 * P1.Y + C2 * P2.Y + C3 * P3.Y);
end;

In FormCreate we set four points (they can be set during program performance):

Code:

  A := Point(763, 310);
  A1 := Point(100, -300);
  B1 := Point(-100, 1500);
  B := Point(763, 0);

In RenderEvent we cause function and Particles:

Code:

   begin
    if (i < 200) then
    begin
      inc(i);
      Count:=200;
      if i mod 3=0 then
      begin
      P := Points(A, A1, B1, B, Count, i);
      XPS:=XPM.Launch('poem2',point2(p.x, p.y));
      XPS.FSettings.ColorStart:= cRGB1(0,0,255,55);
      end;
    end;

They are obediently sprayed, moving on a curve.

The task is solved.. But I in a silly condition once again. I can include particles only on standard events of the form, such as FormClick or FormCreate. Prompt, please, as I can to cause them on Collision. In Hasteroids example collisions are described separately in HAObjects.pas

P.S. to Aegis: Good day and should I begin a new thread?