94 lines
2.8 KiB
Ada
94 lines
2.8 KiB
Ada
with Ada.Numerics.Generic_Complex_Types;
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with SDL.Video.Windows.Makers;
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with SDL.Video.Renderers.Makers;
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with SDL.Video.Palettes;
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with SDL.Events.Events;
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procedure Julia_Set is
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Width : constant := 1_200;
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Height : constant := 900;
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type Real is new Float;
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package Complex_Real is
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new Ada.Numerics.Generic_Complex_Types (Real);
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use Complex_Real;
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Iter : constant := 100;
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C : constant Complex := (Re => -0.70000, Im => 0.27015);
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Move : constant Complex := (Re => 0.000, Im => 0.000);
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Zoom : constant := 0.800;
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Window : SDL.Video.Windows.Window;
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Renderer : SDL.Video.Renderers.Renderer;
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Event : SDL.Events.Events.Events;
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function Map (Width, Height : in Integer;
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X, Y : in Integer) return Complex
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is
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C : Complex;
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L : constant Real := Real (Integer'Max (Width, Height));
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begin
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C := (2.0 * Real (X - Width / 2) / (L * Zoom),
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2.0 * Real (Y - Height / 2) / (L * Zoom));
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return C + Move;
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end Map;
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procedure Draw_Julia_Set is
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use type SDL.C.int;
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use SDL.Video.Palettes;
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Z : Complex;
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begin
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for Y in 0 .. Height loop
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for X in 0 .. Width loop
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Z := Map (Width, Height, X, Y);
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for N in 1 .. Iter loop
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Z := Z ** 2 + C;
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if abs (Z) > 2.0 then
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Renderer.Set_Draw_Colour ((Red => 2 * Colour_Component (N),
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Green => 255 - 2 * Colour_Component (N),
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Blue => 150, Alpha => 255));
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Renderer.Draw (Point => (X => SDL.C.int (X),
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Y => SDL.C.int (Y)));
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exit;
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end if;
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end loop;
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end loop;
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end loop;
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end Draw_Julia_Set;
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procedure Wait is
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use type SDL.Events.Event_Types;
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begin
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loop
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while SDL.Events.Events.Poll (Event) loop
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if Event.Common.Event_Type = SDL.Events.Quit then
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return;
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end if;
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end loop;
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end loop;
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end Wait;
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begin
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if not SDL.Initialise (Flags => SDL.Enable_Screen) then
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return;
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end if;
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SDL.Video.Windows.Makers.Create (Win => Window,
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Title => "Julia set",
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Position => SDL.Natural_Coordinates'(X => 10, Y => 10),
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Size => SDL.Positive_Sizes'(Width, Height),
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Flags => 0);
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SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface);
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Renderer.Set_Draw_Colour ((0, 0, 0, 255));
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Renderer.Fill (Rectangle => (0, 0, Width, Height));
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Draw_Julia_Set;
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Window.Update_Surface;
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Wait;
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Window.Finalize;
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SDL.Finalise;
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end Julia_Set;
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