Image noise

Image noise
You are encouraged to solve this task according to the task description, using any language you may know.

Generate a random black and white 320x240 image continuously, showing FPS (frames per second).

Sample image:

C

Translation of: OCaml

Library: SDL

<lang c>#include <stdlib.h>

1. include <stdio.h>
2. include <time.h>
3. include <SDL/SDL.h>

unsigned int frames = 0; unsigned int t_acc = 0;

void print_fps () {

 static Uint32 last_t = 0;
 Uint32 t = SDL_GetTicks();
 Uint32 dt = t - last_t;
 t_acc += dt;
 if (t_acc > 1000)
 {
   unsigned int el_time = t_acc / 1000;
   printf("- fps: %g\n",
           (float) frames / (float) el_time);
   t_acc = 0;
   frames = 0;
 }
 last_t = t;

}

void blit_noise(SDL_Surface *surf) {

 unsigned int i;
 long dim = surf->w * surf->h;
 while (1)
 {
   SDL_LockSurface(surf);
   for (i=0; i < dim; ++i) {
     ((unsigned char *)surf->pixels)[i] = ((rand() & 1) ? 255 : 0);
   }
   SDL_UnlockSurface(surf);
   SDL_Flip(surf);
   ++frames;
   print_fps();
 }

}

int main(void) {

 SDL_Surface *surf = NULL;
 srand((unsigned int)time(NULL));
 SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO);
 surf = SDL_SetVideoMode(320, 240, 8, SDL_DOUBLEBUF | SDL_HWSURFACE);
 blit_noise(surf);

}</lang>

C#

Max 185 FPS on .NET 4.0/Windows 7 64-bit on Athlon II X4 620 - ATI Radeon X1200.

<lang csharp>using System; using System.Collections.Generic; using System.ComponentModel; using System.Drawing; using System.Drawing.Imaging; using System.Linq; using System.Runtime.InteropServices; using System.Windows.Forms;

class Program {

   static Size size = new Size(320, 240);
   static Rectangle rectsize = new Rectangle(new Point(0, 0), size);
   static int numpixels = size.Width * size.Height;
   static int numbytes = numpixels * 3;

   static PictureBox pb;
   static BackgroundWorker worker;

   static double time = 0;
   static double frames = 0;
   static Random rand = new Random();

   static byte tmp;
   static byte white = 255;
   static byte black = 0;
   static int halfmax = int.MaxValue / 2; // more voodoo! calling Next() is faster than Next(2)!

   static IEnumerable<byte> YieldVodoo()
   {
       // Yield 3 times same number (i.e 255 255 255) for numpixels times. 

       for (int i = 0; i < numpixels; i++)
       {
           tmp = rand.Next() < halfmax ? black : white; // no more lists!  

           // no more loops! yield! yield! yield!
           yield return tmp;
           yield return tmp;
           yield return tmp;
       }
   }

   static Image Randimg()
   {
       // Low-level bitmaps  
       var bitmap = new Bitmap(size.Width, size.Height);
       var data = bitmap.LockBits(rectsize, ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);

       Marshal.Copy(
           YieldVodoo().ToArray<byte>(),// source
           0, // start
           data.Scan0, // scan0 is a pointer to low-level bitmap data
           numbytes); // number of bytes in source

       bitmap.UnlockBits(data);
       return bitmap;
   }

   [STAThread]
   static void Main()
   {
       var form = new Form();

       form.AutoSize = true;
       form.Size = new Size(0, 0);
       form.Text = "Test";

       form.FormClosed += delegate
       {
           Application.Exit();
       };

       worker = new BackgroundWorker();

       worker.DoWork += delegate
       {
           System.Threading.Thread.Sleep(500); // remove try/catch, just wait a bit before looping

           while (true)
           {
               var a = DateTime.Now;
               pb.Image = Randimg();
               var b = DateTime.Now;

               time += (b - a).TotalSeconds;
               frames += 1;

               if (frames == 30)
               {
                   Console.WriteLine("{0} frames in {1:0.000} seconds. ({2:0} FPS)", frames, time, frames / time);

                   time = 0;
                   frames = 0;
               }
           }
       };

       worker.RunWorkerAsync();

       FlowLayoutPanel flp = new FlowLayoutPanel();
       form.Controls.Add(flp);

       pb = new PictureBox();
       pb.Size = size;

       flp.AutoSize = true;
       flp.Controls.Add(pb);

       form.Show();
       Application.Run();
   }

}</lang>

D

Translation of: C

<lang D>import std.stdio, std.random, sdl.SDL;

void main() {

 SDL_Init(SDL_INIT_TIMER | SDL_INIT_VIDEO);
 auto surface = SDL_SetVideoMode(320,240,8, SDL_DOUBLEBUF|SDL_HWSURFACE);

 uint frameNumber, totalTime, lastTime;
 while (true) {
   SDL_LockSurface(surface);
   foreach (i; 0 .. surface.w * surface.h)
     (cast(ubyte*)surface.pixels)[i] = (uniform(0, 2) ? 255 : 0);
   SDL_UnlockSurface(surface);
   SDL_Flip(surface);
   frameNumber++;

   uint time = SDL_GetTicks();
   totalTime += time - lastTime;
   if (totalTime > 1000) {
     writeln("FPS: ", frameNumber / (totalTime / 1000.0));
     totalTime = frameNumber = 0;
   }
   lastTime = time;
 }

}</lang> This D version shows about 155 FPS, while on the same PC the C version shows about 180 FPS.

Generating random bits with the C core.stdc.stdlib.rand the performance becomes about the same of the C version.

Factor

By some reason, FPS does not show during execution on Linux.

Max 2 FPS on Factor 0.94 x86-64/Windows 7 64-bits - Athlon II X4 620 - ATI Radeon X1200.

<lang factor>USING: namespaces ui ui.gadgets ui.gadgets.buttons ui.gadgets.tracks ui.gadgets.borders images images.viewer models timers accessors kernel sequences sequences.deep byte-vectors random calendar io math math.functions math.parser prettyprint debugger system ; FROM: models => change-model ;

IN: imagenoise

TUPLE: imgmodel < model content ; SYMBOL: dispimg SYMBOL: num SYMBOL: ttime

randimg ( -- img )

<image>
 { 320 240 } >>dim
 RGB >>component-order
 ubyte-components >>component-type

 dup dim>> product
 [ { 255 0 } random 3 swap <repetition> ] replicate flatten >byte-vector >>bitmap ;

randimg imgmodel new-model dispimg set-global 0 num set-global 0 ttime set-global

[

 now

 dispimg get-global
 [ drop randimg ] change-model
 num get-global 1 +
 num set-global

 now swap time- duration>seconds
 ttime get-global +  
 ttime set-global
 
 num get-global 10 <= 
  [ ]
  [
   num get-global 
   ttime get-global 
   [ / round number>string " FPS" append ] try print

   0 num set-global
   0 ttime set-global ] if  

] 1 nanoseconds every

[ vertical <track>

dispimg get-global <image-control> { 5 5 } <border> f track-add  
 
"Test" open-window

] with-ui</lang>

J

<lang j>coclass'example' (coinsert[require)'jzopengl'

P=: 0 : 0 pc p nosize; xywh 0 0 160 120;cc c isigraph opengl; pas 0 0;pcenter; rem form end;

pshow;
timer 1;

)

timestamp=: (6!:8) %~ 6!:9

create=:3 :0

 ogl=:conew'jzopengl'
 frames=:0
 start=: timestamp
 sys_timer_base_=: 1 :('p_c_paint_',(;coname),'_')
 wd P

)

p_run=: 3 : 0

 conew'example'

)

destroy=:3 :0

 end=:timestamp
 smoutput 'frames per second: ',":frames%end-start
 wd 'timer 0'
 destroy__ogl
 wd'pclose'
 codestroy

)

p_close=: destroy

p_c_paint=: 3 : 0

 rc__ogl
 glClear GL_COLOR_BUFFER_BIT
 glBegin GL_POINTS
   glVertex _1+2*53050 2?@$ 0
 glEnd
 show__ogl
 frames=:frames+1

)

p_run</lang>

The script auto-starts when run (that last line p_run'' is responsible for the auto-start.

Average FPS are displayed when the window is closed.

With this revision, on my laptop, I typically get in the range of 58..59 FPS, with a cpu load from J of about 3% (sometimes as much as 5%, sometimes as low as 0.1%). I am probably limited by v-sync, and (hypothetically speaking) if I tuned my opengl drivers I perhaps could get significantly faster fps. However, since my screen only refreshes approximately 60 times per second, anything over that would be meaningless.

JavaScript

<lang javascript><body>

 <canvas id='c'></canvas>
 <script>

var canvas = document.getElementById('c'); var ctx = canvas.getContext('2d');

var w = canvas.width = 320; var h = canvas.height = 240; var t1 = new Date().getTime(); var frame_count = 0; ctx.font = 'normal 400 24px/2 Unknown Font, sans-serif'; var img = ctx.createImageData(w,h);

function animate() {

   for (var x = 0; x < w; x++)
   {
       for (var y = 0; y < h; y++)
       {
           var index = 4* (x + w*y);
           var value = (Math.random() > 0.5) ? 255 : 0;
           img.data[index] = value;
           img.data[index+1] = value;
           img.data[index+2] = value;
           img.data[index+3] = 255;
       }
   }
   
   ctx.putImageData(img,0,0);

   frame_count++;
   var fps = frame_count / (new Date().getTime() - t1) * 1000;
   ctx.fillStyle = "red";
   ctx.fillText(fps.toFixed(2) + " fps", 20, 40);

   setTimeout(animate, 0);

}

animate();

 </script>

</body></lang>

OCaml

Library: OCamlSDL

with the ocaml-sdl bindings: <lang ocaml>let frames =

 { contents = 0 }

let t_acc =

 { contents = 0 }

let last_t =

 { contents = Sdltimer.get_ticks () }

let print_fps () =

 let t = Sdltimer.get_ticks () in
 let dt = t - !last_t in
 t_acc := !t_acc + dt;
 if !t_acc > 1000 then begin
   let el_time = !t_acc / 1000 in
   Printf.printf
     "- fps: %g\n%!"
     (float !frames /. float el_time);
   t_acc := 0;
   frames := 0;
 end;
 last_t := t

let blit_noise surf =

 let ba = Sdlvideo.pixel_data_8 surf in
 let dim = Bigarray.Array1.dim ba in
 let rec aux () =
   for i = 0 to pred dim do
     ba.{i} <- if Random.bool () then max_int else 0
   done;
   Sdlvideo.flip surf;
   incr frames;
   print_fps ();
   aux ()
 in
 aux ()

let blit_noise surf =

 try blit_noise surf
 with _ -> Sdl.quit ()

let () =

 Sdl.init [`VIDEO; `TIMER];
 Random.self_init();
 let surf =
   Sdlvideo.set_video_mode
     ~w:320 ~h:240 ~bpp:8
     [(*`HWSURFACE;*) `DOUBLEBUF]
 in
 Sys.catch_break true;
 blit_noise surf</lang>

compile to native-code with:

ocamlopt bigarray.cmxa -I +sdl sdl.cmxa noise_fps_sdl.ml -o noise_fps_sdl.opt

or using findlib:

ocamlfind opt -linkpkg -package sdl noise_fps_sdl.ml
./a.out

compile to bytecode with:

ocamlc bigarray.cma -I +sdl sdl.cma noise_fps_sdl.ml -o noise_fps_sdl.byte

In script mode, run with:

ocaml bigarray.cma -I +sdl sdl.cma noise_fps_sdl.ml

---

In a more idiomatic way, using the modules Graphics and Unix from the standard OCaml library: <lang ocaml>open Graphics

let white = (rgb 255 255 255) let black = (rgb 0 0 0)

let t_last = ref (Unix.gettimeofday())

let () =

 open_graph "";
 let width = 320
 and height = 240 in
 resize_window width height;
 try 
   while true do
     for y = 0 to pred height do
       for x = 0 to pred width do
         set_color (if Random.bool() then white else black);
         plot x y
       done;
     done;
     let t = Unix.gettimeofday() in
     Printf.printf "- fps: %f\n" (1.0 /. (t -. !t_last));
     t_last := t
   done
 with _ ->
   flush stdout;
   close_graph ()</lang>

run this script with:

ocaml unix.cma graphics.cma g.ml

---

And using an OCaml-Xlib bindings, or an OCaml-Allegro binding.

PicoLisp

This solution works on ErsatzLisp, the Java version of PicoLisp. It creates a 'JFrame' window, and calls inlined Java code to handle the image. <lang PicoLisp>(javac "ImageNoise" "JPanel" NIL

     "java.util.*"
     "java.awt.*" "java.awt.image.*" "javax.swing.*" )
  int DX, DY;
  int[] Pixels;
  MemoryImageSource Source;
  Image Img;
  Random Rnd;

  public ImageNoise(int dx, int dy) {
     DX = dx;
     DY = dy;
     Pixels = new int[DX * DY];
     Source = new MemoryImageSource(DX, DY, Pixels, 0, DX);
     Source.setAnimated(true);
     Img = createImage(Source);
     Rnd = new Random();
  }

  public void paint(Graphics g) {update(g);}
  public void update(Graphics g) {g.drawImage(Img, 0, 0, this);}

  public void draw() {
     for (int i = 0; i < Pixels.length; ++i) {
        int c = Rnd.nextInt(255);
        Pixels[i] = 0xFF000000 | c<<16 | c<<8 | c;
     }
     Source.newPixels();
     paint(getGraphics());
  }

/**/

(de imageNoise (DX DY Fps)

  (let
     (Frame (java "javax.swing.JFrame" T "Image Noise")
        Noise (java "ImageNoise" T DX DY) )
     (java Frame "add" Noise)
     (java Frame "setSize" DX DY)
     (java Frame "setVisible" T)
     (task (/ -1000 Fps) 0
        Image Noise
        (java Image "draw") ) ) )

1. Start with 25 frames per second

(imageNoise 320 240 25)</lang>

PureBasic

<lang PureBasic>#filter=0.2  ; Filter parameter for the FPS-calculation

1. UpdateFreq=100  ; How often to update the FPS-display

OpenWindow(0,400,300,320,240,"PureBasic") Define w=WindowWidth(0), h=WindowHeight(0) Define x, y, T, TOld, FloatingMedium.f, cnt InitSprite() OpenWindowedScreen(WindowID(0),0,0,w,h,1,0,0,#PB_Screen_NoSynchronization) Repeat

 StartDrawing(ScreenOutput())
 For y=0 To h-1
   For x=0 To w-1
     If Random(1)
       Plot(x,y,#Black)
     Else
       Plot(x,y,#White)
     EndIf
   Next
 Next
 StopDrawing()
 FlipBuffers()
 cnt+1
 If cnt>=#UpdateFreq
   cnt =0
   TOld=T
   T   =ElapsedMilliseconds()
   FloatingMedium*(1-#filter)+1000*#filter/(T-TOld)
   SetWindowTitle(0,"PureBasic: "+StrF(#UpdateFreq*FloatingMedium,2)+" FPS")
   Repeat ; Handle all events
     Event=WindowEvent()
     If Event=#PB_Event_CloseWindow
       End
     EndIf
   Until Not Event
 EndIf

ForEver</lang>

Python

Library: Tkinter

Library: PIL

Max 23 FPS on Python 2.7 (r27:82525 MSC v.1500 32 bit Intel), Windows 7 64-bit on Athlon II X4 620 - ATI Radeon X1200.

<lang python>import Tkinter import Image, ImageTk import random import time

size = (320,240) pixels = size[0] * size[1]

class App():

   def __init__(self, root):  
       self.root = root
       self.root.title("Test")
       
       self.img = Image.new("RGB",size)        
       self.label = Tkinter.Label(root)
       self.label.pack()

       self.time = 0.0
       self.frames = 0        
       self.loop() 
   def loop(self):
       self.ta = time.time()
       # 13 FPS boost. half integer idea from C#.
       self.img.putdata([(255,255,255) if random.random() > 0.5 else (0,0,0) for i in range(pixels)])
       self.pimg = ImageTk.PhotoImage(self.img)
       self.label["image"] = self.pimg        
       self.tb = time.time()
       
       self.time += (self.tb - self.ta)
       self.frames += 1

       if self.frames == 30:
           try:
               self.fps = self.frames / self.time
           except:
               self.fps = "INSTANT"
           print "%d frames in %3.2f seconds (%s FPS)" % (self.frames, self.time, self.fps)
           self.time = 0
           self.frames = 0
     
       self.root.after(1, self.loop)

root = Tkinter.Tk() app = App(root) root.mainloop()</lang>

Tcl

Library: Tk

<lang tcl>package require Tk

proc generate {img width height} {

   set data {}
   for {set i 0} {$i<$height} {incr i} {

set line {} for {set j 0} {$j<$width} {incr j} { lappend line [lindex "#000000 #FFFFFF" [expr {rand() < 0.5}]] } lappend data $line

   }
   $img put $data

}

set time 0.0 set count 0

proc looper {} {

   global time count
   set t [lindex [time {generate noise 320 240}] 0]
   set time [expr {$time + $t}]
   if {[incr count] >= 30} {

set time [expr {$time / 1000000.0}] set fps [expr {$count / $time}] puts [format "%d frames in %3.2f seconds (%f FPS)" $count $time $fps] set time 0.0 set count 0

   }
   after 1 looper

}

image create photo noise -width 320 -height 240 pack [label .l -image noise] update looper</lang>