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169 | with Ada.Exceptions;
use Ada.Exceptions;
with Ada.Numerics.Elementary_Functions;
use Ada.Numerics.Elementary_Functions;
with Ada.Finalization;
with Ada.Calendar;
with Ada.Unchecked_Deallocation;
with Ada.Numerics.Generic_Complex_Types;
with Ada.Text_IO.Complex_IO;
with Ada.Text_IO;
use Ada.Text_IO;
with Ada.Streams;
use Ada.Streams;
-- Taken from https://ideone.com/a1ky4l
-- Author: David Given http://cowlark.com/
procedure Mandelbrot_Ascii is
-- We want to use complex numbers, which are defined in the Ada standard
-- library as a generic. (So you get to pick which precision you want.)
package Complex_Types is new Ada.Numerics.Generic_Complex_Types(float);
use Complex_Types;
-- Configuration constants.
bitmapsize: constant := 128; -- pixels
maxiterations: constant := 32;
threads: constant := 4;
-- Returns the intensity of a single point in the Mandelbrot set.
function RenderPixel(c: Complex) return float is
z: Complex := Complex'(0.0, 0.0);
begin
for n in integer range 0..maxiterations loop
z := z*z + c;
if (abs z > 2.0) then
return float(n) / float(maxiterations);
end if;
end loop;
return 0.0;
end;
-- The bitmap (well, floatmap) which the rendered Mandelbrot is going to
-- live in.
type Bitmap is array(integer range <>, integer range <>) of float;
type BitmapRef is access Bitmap;
-- Encapsulates the multithreaded render: creates a bunch of workers
-- and a scheduler, which hands out work units to the renderers.
procedure Mandelbrot(data: BitmapRef;
r1, i1, r2, i2: float) is
width: integer := data'length(1);
height: integer := data'length(2);
xdelta: float := (r2-r1) / float(width);
ydelta: float := (i2-i1) / float(height);
task Scheduler is
-- Each worker calls this to find out what it needs to do.
entry RequestWorkUnit(y: out integer; i: out float);
end;
task body Scheduler is
begin
-- Hand out each scanline in turn to tasks that want things to
-- do, then exit.
for yy in data'range(2) loop
accept RequestWorkUnit(y: out integer; i: out float) do
y := yy;
i := i1 + float(yy)*ydelta;
end RequestWorkUnit;
end loop;
end;
-- Actually does the rendering. Each of these is self contained and will
-- keep working until there's nothing left to do, at which point it
-- exits.
task type Worker;
task body Worker is
y: integer;
i: float;
c: Complex;
begin
-- Keep asking for stuff to do, then do it. When the Scheduler
-- has terminated, requesting a work unit will throw an exception and
-- the task will safely exit.
loop
Scheduler.RequestWorkUnit(y, i);
for x in data'range(1) loop
c := Complex'(r1 + float(x)*xdelta, i);
data(x, y) := RenderPixel(c);
end loop;
end loop;
end;
-- Create some work threads (which will automatically start).
scanlines: array(integer range 1..threads) of Worker;
begin
null; -- nothing to do in the main body, just wait for tasks to exit
end;
-- This sucks, but I couldn't find any other way to get ideone to emit
-- Unicode procedurally. (The UTF-8 representation of each of these is
-- three bytes. Coincidence? I think not.)
glyphs: constant array(0..255) of string(1..3) :=
("⠀", "⠁", "⠂", "⠃", "⠄", "⠅", "⠆", "⠇", "⠈", "⠉", "⠊", "⠋", "⠌", "⠍",
"⠎", "⠏", "⠐", "⠑", "⠒", "⠓", "⠔", "⠕", "⠖", "⠗", "⠘", "⠙", "⠚", "⠛",
"⠜", "⠝", "⠞", "⠟", "⠠", "⠡", "⠢", "⠣", "⠤", "⠥", "⠦", "⠧", "⠨", "⠩",
"⠪", "⠫", "⠬", "⠭", "⠮", "⠯", "⠰", "⠱", "⠲", "⠳", "⠴", "⠵", "⠶", "⠷",
"⠸", "⠹", "⠺", "⠻", "⠼", "⠽", "⠾", "⠿", "⡀", "⡁", "⡂", "⡃", "⡄", "⡅",
"⡆", "⡇", "⡈", "⡉", "⡊", "⡋", "⡌", "⡍", "⡎", "⡏", "⡐", "⡑", "⡒", "⡓",
"⡔", "⡕", "⡖", "⡗", "⡘", "⡙", "⡚", "⡛", "⡜", "⡝", "⡞", "⡟", "⡠", "⡡",
"⡢", "⡣", "⡤", "⡥", "⡦", "⡧", "⡨", "⡩", "⡪", "⡫", "⡬", "⡭", "⡮", "⡯",
"⡰", "⡱", "⡲", "⡳", "⡴", "⡵", "⡶", "⡷", "⡸", "⡹", "⡺", "⡻", "⡼", "⡽",
"⡾", "⡿", "⢀", "⢁", "⢂", "⢃", "⢄", "⢅", "⢆", "⢇", "⢈", "⢉", "⢊", "⢋",
"⢌", "⢍", "⢎", "⢏", "⢐", "⢑", "⢒", "⢓", "⢔", "⢕", "⢖", "⢗", "⢘", "⢙",
"⢚", "⢛", "⢜", "⢝", "⢞", "⢟", "⢠", "⢡", "⢢", "⢣", "⢤", "⢥", "⢦", "⢧",
"⢨", "⢩", "⢪", "⢫", "⢬", "⢭", "⢮", "⢯", "⢰", "⢱", "⢲", "⢳", "⢴", "⢵",
"⢶", "⢷", "⢸", "⢹", "⢺", "⢻", "⢼", "⢽", "⢾", "⢿", "⣀", "⣁", "⣂", "⣃",
"⣄", "⣅", "⣆", "⣇", "⣈", "⣉", "⣊", "⣋", "⣌", "⣍", "⣎", "⣏", "⣐", "⣑",
"⣒", "⣓", "⣔", "⣕", "⣖", "⣗", "⣘", "⣙", "⣚", "⣛", "⣜", "⣝", "⣞", "⣟",
"⣠", "⣡", "⣢", "⣣", "⣤", "⣥", "⣦", "⣧", "⣨", "⣩", "⣪", "⣫", "⣬", "⣭",
"⣮", "⣯", "⣰", "⣱", "⣲", "⣳", "⣴", "⣵", "⣶", "⣷", "⣸", "⣹", "⣺", "⣻",
"⣼", "⣽", "⣾", "⣿");
-- Writes the bitmap to stdout, using funky Unicode hackery to make it
-- look pretty. Sort of.
procedure DumpBitmap(data: BitmapRef) is
function IsSet(x, y: integer) return boolean is
begin
return data(x, y) > 0.0;
end;
type byte is mod 2**8;
x, y: integer;
b: byte;
begin
y := 0;
while (y <= data'last(2)) loop
x := 0;
while (x < data'last(1)) loop
b := 0;
if IsSet(x+0, y+0) then b := b or 1; end if;
if IsSet(x+0, y+1) then b := b or 2; end if;
if IsSet(x+0, y+2) then b := b or 4; end if;
if IsSet(x+0, y+3) then b := b or 64; end if;
if IsSet(x+1, y+0) then b := b or 8; end if;
if IsSet(x+1, y+1) then b := b or 16; end if;
if IsSet(x+1, y+2) then b := b or 32; end if;
if IsSet(x+1, y+3) then b := b or 128; end if;
Put(glyphs(byte'pos(b)));
x := x + 2;
end loop;
Put_Line("");
y := y + 4;
end loop;
end;
image: BitmapRef;
width: constant := bitmapsize;
height: constant := width;
begin
-- Render, print, then leak a bitmap.
image := new Bitmap(0..(width-1), 0..(height-1));
Mandelbrot(image, -2.0, -2.0, +2.0, +2.0);
DumpBitmap(image);
exception
when e: others =>
Put_Line(Exception_Information(e));
end;
|