RosettaCodeData/Task/Animate-a-pendulum/Ada/animate-a-pendulum-2.ada

39 lines
1.3 KiB
Ada

with Ada.Numerics.Generic_Elementary_Functions;
package body Pendulums is
package Math is new Ada.Numerics.Generic_Elementary_Functions (Float_Type);
function New_Pendulum (Length : Float_Type;
Theta0 : Float_Type) return Pendulum is
Result : Pendulum;
begin
Result.Length := Length;
Result.Theta := Theta0 / 180.0 * Ada.Numerics.Pi;
Result.X := Math.Sin (Theta0) * Length;
Result.Y := Math.Cos (Theta0) * Length;
Result.Velocity := 0.0;
return Result;
end New_Pendulum;
function Get_X (From : Pendulum) return Float_Type is
begin
return From.X;
end Get_X;
function Get_Y (From : Pendulum) return Float_Type is
begin
return From.Y;
end Get_Y;
procedure Update_Pendulum (Item : in out Pendulum; Time : in Duration) is
Acceleration : constant Float_Type := Gravitation / Item.Length *
Math.Sin (Item.Theta);
begin
Item.X := Math.Sin (Item.Theta) * Item.Length;
Item.Y := Math.Cos (Item.Theta) * Item.Length;
Item.Velocity := Item.Velocity +
Acceleration * Float_Type (Time);
Item.Theta := Item.Theta +
Item.Velocity * Float_Type (Time);
end Update_Pendulum;
end Pendulums;