Image noise: Difference between revisions

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#include <windows.h>
#include <windows.h>
#include <sstream>
#include <sstream>
#include <tchar.h>
//--------------------------------------------------------------------------------------------------
//--------------------------------------------------------------------------------------------------
using namespace std;
using namespace std;

Revision as of 17:05, 3 February 2018

Task
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:

Ada

Library: Lumen

noise.ads: <lang Ada>with Lumen.Image;

package Noise is 

  function Create_Image (Width, Height : Natural) return Lumen.Image.Descriptor;

end Noise;</lang>

noise.adb: <lang Ada>with Ada.Numerics.Discrete_Random;

package body Noise is 

  type Color is (Black, White);
  package Color_Random is new Ada.Numerics.Discrete_Random (Color);
  Color_Gen : Color_Random.Generator;

  function Create_Image (Width, Height : Natural) return Lumen.Image.Descriptor is
     Result : Lumen.Image.Descriptor;
  begin
     Color_Random.Reset (Color_Gen);
     Result.Width := Width;
     Result.Height := Height;
     Result.Complete := True;
     Result.Values := new Lumen.Image.Pixel_Matrix (1 .. Width, 1 .. Height);
     for X in 1 .. Width loop
        for Y in 1 .. Height loop
           if Color_Random.Random (Color_Gen) = Black then
              Result.Values (X, Y) := (R => 0, G => 0, B => 0, A => 0);
           else
              Result.Values (X, Y) := (R => 255, G => 255, B => 255, A => 0);
           end if;
        end loop;
     end loop;
     return Result;
  end Create_Image;

end Noise;</lang>

test_noise.adb: <lang Ada>with Ada.Calendar; with Ada.Text_IO; with System.Address_To_Access_Conversions; with Lumen.Window; with Lumen.Image; with Lumen.Events.Animate; with GL; with Noise;

procedure Test_Noise is 

  package Float_IO is new Ada.Text_IO.Float_IO (Float);

  Program_End : exception;

  Win : Lumen.Window.Handle;
  Image : Lumen.Image.Descriptor;
  Tx_Name : aliased GL.GLuint;
  Wide : Natural := 320;
  High : Natural := 240;
  First_Frame : Ada.Calendar.Time;
  Frame_Count : Natural := 0;

  -- Create a texture and bind a 2D image to it
  procedure Create_Texture is
     use GL;

     package GLB is new System.Address_To_Access_Conversions (GLubyte);

     IP : GLpointer;
  begin  -- Create_Texture
     -- Allocate a texture name
     glGenTextures (1, Tx_Name'Unchecked_Access);

     -- Bind texture operations to the newly-created texture name
     glBindTexture (GL_TEXTURE_2D, Tx_Name);

     -- Select modulate to mix texture with color for shading
     glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

     -- Wrap textures at both edges
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

     -- How the texture behaves when minified and magnified
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

     -- Create a pointer to the image.  This sort of horror show is going to
     -- be disappearing once Lumen includes its own OpenGL bindings.
     IP := GLB.To_Pointer (Image.Values.all'Address).all'Unchecked_Access;

     -- Build our texture from the image we loaded earlier
     glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, GLsizei (Image.Width), GLsizei (Image.Height), 0,
                   GL_RGBA, GL_UNSIGNED_BYTE, IP);
  end Create_Texture;

  -- Set or reset the window view parameters
  procedure Set_View (W, H : in Natural) is
     use GL;
  begin  -- Set_View
     GL.glEnable (GL.GL_TEXTURE_2D);
     glClearColor (0.8, 0.8, 0.8, 1.0);

     glMatrixMode (GL_PROJECTION);
     glLoadIdentity;
     glViewport (0, 0, GLsizei (W), GLsizei (H));
     glOrtho (0.0, GLdouble (W), GLdouble (H), 0.0, -1.0, 1.0);

     glMatrixMode (GL_MODELVIEW);
     glLoadIdentity;
  end Set_View;

  -- Draw our scene
  procedure Draw is
     use GL;
  begin  -- Draw
     -- clear the screen
     glClear (GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
     GL.glBindTexture (GL.GL_TEXTURE_2D, Tx_Name);

     -- fill with a single textured quad
     glBegin (GL_QUADS);
     begin
        glTexCoord2f (1.0, 0.0);
        glVertex2i (GLint (Wide), 0);

        glTexCoord2f (0.0, 0.0);
        glVertex2i (0, 0);

        glTexCoord2f (0.0, 1.0);
        glVertex2i (0, GLint (High));

        glTexCoord2f (1.0, 1.0);
        glVertex2i (GLint (Wide), GLint (High));
     end;
     glEnd;

     -- flush rendering pipeline
     glFlush;

     -- Now show it
     Lumen.Window.Swap (Win);
  end Draw;

  -- Simple event handler routine for keypresses and close-window events
  procedure Quit_Handler (Event : in Lumen.Events.Event_Data) is
  begin  -- Quit_Handler
     raise Program_End;
  end Quit_Handler;

  -- Simple event handler routine for Exposed events
  procedure Expose_Handler (Event : in Lumen.Events.Event_Data) is
     pragma Unreferenced (Event);
  begin  -- Expose_Handler
     Draw;
  end Expose_Handler;

  -- Simple event handler routine for Resized events
  procedure Resize_Handler (Event : in Lumen.Events.Event_Data) is
  begin  -- Resize_Handler
     Wide := Event.Resize_Data.Width;
     High := Event.Resize_Data.Height;
     Set_View (Wide, High);
     Draw;
  end Resize_Handler;

  procedure Next_Frame (Frame_Delta : in Duration) is
     pragma Unreferenced (Frame_Delta);
     use type Ada.Calendar.Time;
  begin
     Frame_Count := Frame_Count + 1;
     if Ada.Calendar.Clock >= First_Frame + 1.0 then
        Ada.Text_IO.Put ("FPS: ");
        Float_IO.Put (Float (Frame_Count), 5, 1, 0);
        Ada.Text_IO.New_Line;
        First_Frame := Ada.Calendar.Clock;
        Frame_Count := 0;
     end if;
     Image := Noise.Create_Image (Width => Wide, Height => High);
     Create_Texture;
     Draw;
  end Next_Frame;

begin 

  -- Create Lumen window, accepting most defaults; turn double buffering off
  -- for simplicity
  Lumen.Window.Create (Win           => Win,
                       Name          => "Noise fractal",
                       Width         => Wide,
                       Height        => High,
                       Events        => (Lumen.Window.Want_Exposure  => True,
                                         Lumen.Window.Want_Key_Press => True,
                                         others                      => False));

  -- Set up the viewport and scene parameters
  Set_View (Wide, High);

  -- Now create the texture and set up to use it
  Image := Noise.Create_Image (Width => Wide, Height => High);
  Create_Texture;

  First_Frame := Ada.Calendar.Clock;

  -- Enter the event loop
  declare
     use Lumen.Events;
  begin
     Animate.Select_Events (Win   => Win,
                            Calls => (Key_Press    => Quit_Handler'Unrestricted_Access,
                                      Exposed      => Expose_Handler'Unrestricted_Access,
                                      Resized      => Resize_Handler'Unrestricted_Access,
                                      Close_Window => Quit_Handler'Unrestricted_Access,
                                      others       => No_Callback),
                            FPS   => Animate.Flat_Out,
                            Frame => Next_Frame'Unrestricted_Access);
  end;

exception 

  when Program_End =>
     null;

end Test_Noise;</lang>

Axe

Note that since the calculator's screen is 96x64, this example uses those dimensions instead of 320x240.

Instead of naively drawing each pixel to the screen, this implementation directly writes random numbers to the buffer, which randomly sets each pixel. Because Axe does not have native clock support, the FPS counter is simulated by counting "ticks" at the known interrupt rate of 107.79 Hz (rounded to 108).

It is possible to notice some vertical line patterns in the noise. This is likely due to the pseudorandom number generator and not the drawing method.

This example gets steady 48 FPS on a TI-84 Plus Silver Edition running at 15 MHz. It gets 26 FPS when running at 6 MHz. Some pixels appear gray because the duration of each frame is shorter than the screen's notoriously slow response time. If a pixel is toggled very quickly, it never has time to fully transition to white or black.

<lang axe>.Enable 15 MHz full speed mode Full .Disable memory access delays (adds 1 FPS) Fullʳ

.Flush key presses While getKey(0) End

.Setup 0→F 0→N Fix 5 fnInt(FPS,6)

Repeat getKey(0) 

NOISE()
F++
.Reset the FPS counter before it overflows
F>606?0→F→N
Text(0,0,F*108/N▶Dec)
DispGraph

End

.Clean up LnRegʳ Fix 4 Return

.Draws random noise to the buffer Lbl NOISE ClrDraw For(I,0,5) 

For(J,0,63)
 rand→{J*12+(I*2)+L₆}ʳ
End

End Return

.Increments the tick counter Lbl FPS N++ Return</lang>

BBC BASIC

Works with: BBC BASIC for Windows

<lang bbcbasic> dx% = 320 

     dy% = 240
     images% = 100000
     VDU 23,22,dx%;dy%;8,8,16,0
     
     REM Create a block of random data in memory:
     DIM random% dx%*dy%+images%
     FOR R% = random% TO random%+dx%*dy%+images%
       ?R% = RND(256)-1
     NEXT
     
     REM Create a BMP file structure:
     DIM bmpfile{bfType{l&,h&}, bfSize%, bfReserved%, bfOffBits%, \
     \   biSize%, biWidth%, biHeight%, biPlanes{l&,h&}, biBitCount{l&,h&}, \
     \   biCompression%, biSizeImage%, biXPelsPerMeter%, biYPelsPerMeter%, \
     \   biClrUsed%, biClrImportant%, biPalette%(255)}
     bmpfile.biSize% = 40
     bmpfile.biWidth% = dx%
     bmpfile.biHeight% = dy%
     bmpfile.biPlanes.l& = 1
     bmpfile.biBitCount.l& = 8
     FOR C% = 0 TO 255
       bmpfile.biPalette%(C%) = C% OR C%<<8 OR C%<<16
     NEXT
     
     REM Display image at a random offset into the data:
     frame% = 0
     TIME = 0
     REPEAT
       bmpfile.bfOffBits% = random% - bmpfile{} + RND(images%)
       OSCLI "MDISPLAY " + STR$~bmpfile{}
       frame% += 1
       IF TIME>10 THEN
         SYS "SetWindowText", @hwnd%, "BBC BASIC: " + STR$(frame%*100 DIV TIME) + " fps"
       ENDIF
     UNTIL FALSE</lang>

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>

Fast OpenGL method

Library: GLUT

Depending on your hardware, you might be able to get thousands of frames per second. Compiled with gcc -lglut -lGL -g -Wall -O2. <lang c>#include <GL/glut.h>

  1. include <GL/gl.h>
  2. include <stdio.h>
  3. include <time.h>
  1. define W 320
  2. define H 240
  3. define slen W * H / sizeof(int)

time_t start, last;

void render() { static int frame = 0, bits[slen]; register int i = slen, r; time_t t;

r = bits[0] + 1; while (i--) r *= 1103515245, bits[i] = r ^ (bits[i] >> 16);

glClear(GL_COLOR_BUFFER_BIT); glBitmap(W, H, 0, 0, 0, 0, (void*)bits); glFlush();

if (!(++frame & 15)) { if ((t = time(0)) > last) { last = t; printf("\rfps: %ld ", frame / (t - start)); fflush(stdout); } } }

int main(int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_INDEX); glutInitWindowSize(W, H); glutCreateWindow("noise"); glutDisplayFunc(render); glutIdleFunc(render);

last = start = time(0);

glutMainLoop(); return 0; }</lang>

C++

<lang cpp>

  1. include <windows.h>
  2. include <sstream>
  3. include <tchar.h>

//-------------------------------------------------------------------------------------------------- using namespace std;

//-------------------------------------------------------------------------------------------------- const unsigned int BMP_WID = 320, BMP_HEI = 240, WHITE = 16777215, BLACK = 0;

//-------------------------------------------------------------------------------------------------- class myBitmap { public: 

   myBitmap() : pen( NULL ), brush( NULL ), clr( 0 ), wid( 1 ) {}
   ~myBitmap()
   {

DeleteObject( pen ); DeleteObject( brush ); DeleteDC( hdc ); DeleteObject( bmp ); 

   }

   bool create( int w, int h )
   {

BITMAPINFO bi; ZeroMemory( &bi, sizeof( bi ) ); bi.bmiHeader.biSize = sizeof( bi.bmiHeader ); bi.bmiHeader.biBitCount = sizeof( DWORD ) * 8; bi.bmiHeader.biCompression = BI_RGB; bi.bmiHeader.biPlanes = 1; bi.bmiHeader.biWidth = w; bi.bmiHeader.biHeight = -h; HDC dc = GetDC( GetConsoleWindow() ); bmp = CreateDIBSection( dc, &bi, DIB_RGB_COLORS, &pBits, NULL, 0 ); if( !bmp ) return false; hdc = CreateCompatibleDC( dc ); SelectObject( hdc, bmp ); ReleaseDC( GetConsoleWindow(), dc ); width = w; height = h; return true; 

   }

   void clear( BYTE clr = 0 )
   {

memset( pBits, clr, width * height * sizeof( DWORD ) ); 

   }

   void setBrushColor( DWORD bClr )
   {

if( brush ) DeleteObject( brush ); brush = CreateSolidBrush( bClr ); SelectObject( hdc, brush ); 

   }

   void setPenColor( DWORD c ) { clr = c; createPen(); }
   void setPenWidth( int w ) { wid = w; createPen(); }
  
   void saveBitmap( string path )
   {

BITMAPFILEHEADER fileheader; BITMAPINFO infoheader; BITMAP bitmap; DWORD wb;

GetObject( bmp, sizeof( bitmap ), &bitmap ); DWORD* dwpBits = new DWORD[bitmap.bmWidth * bitmap.bmHeight]; ZeroMemory( dwpBits, bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ) ); ZeroMemory( &infoheader, sizeof( BITMAPINFO ) ); ZeroMemory( &fileheader, sizeof( BITMAPFILEHEADER ) ); infoheader.bmiHeader.biBitCount = sizeof( DWORD ) * 8; infoheader.bmiHeader.biCompression = BI_RGB; infoheader.bmiHeader.biPlanes = 1; infoheader.bmiHeader.biSize = sizeof( infoheader.bmiHeader ); infoheader.bmiHeader.biHeight = bitmap.bmHeight; infoheader.bmiHeader.biWidth = bitmap.bmWidth; infoheader.bmiHeader.biSizeImage = bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ); fileheader.bfType = 0x4D42; fileheader.bfOffBits = sizeof( infoheader.bmiHeader ) + sizeof( BITMAPFILEHEADER ); fileheader.bfSize = fileheader.bfOffBits + infoheader.bmiHeader.biSizeImage; GetDIBits( hdc, bmp, 0, height, ( LPVOID )dwpBits, &infoheader, DIB_RGB_COLORS ); HANDLE file = CreateFile( path.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL ); WriteFile( file, &fileheader, sizeof( BITMAPFILEHEADER ), &wb, NULL ); WriteFile( file, &infoheader.bmiHeader, sizeof( infoheader.bmiHeader ), &wb, NULL ); WriteFile( file, dwpBits, bitmap.bmWidth * bitmap.bmHeight * 4, &wb, NULL ); CloseHandle( file );

delete [] dwpBits; 

   }

   void* getBits( void ) const { return pBits; }
   HDC getDC() const     { return hdc; }
   int getWidth() const  { return width; }
   int getHeight() const { return height; }

private: 

   void createPen()
   {

if( pen ) DeleteObject( pen ); pen = CreatePen( PS_SOLID, wid, clr ); SelectObject( hdc, pen ); 

   }

   HBITMAP bmp;
   HDC     hdc;
   HPEN    pen;
   HBRUSH  brush;
   void*   pBits;
   int     width, height, wid;
   DWORD   clr;

}; //-------------------------------------------------------------------------------------------------- class bmpNoise { public: 

   bmpNoise()
   {

QueryPerformanceFrequency( &_frequency ); _bmp.create( BMP_WID, BMP_HEI ); _frameTime = _fps = 0; _start = getTime(); _frames = 0; 

   }

   void mainLoop()
   {

float now = getTime(); if( now - _start > 1.0f ) { _fps = static_cast<float>( _frames ) / ( now - _start ); _start = now; _frames = 0; } HDC wdc, dc = _bmp.getDC(); unsigned int* bits = reinterpret_cast<unsigned int*>( _bmp.getBits() );

for( int y = 0; y < BMP_HEI; y++ ) { for( int x = 0; x < BMP_WID; x++ ) { if( rand() % 10 < 5 ) memset( bits, 255, 3 ); else memset( bits, 0, 3 ); bits++; } } ostringstream o; o << _fps; TextOut( dc, 0, 0, o.str().c_str(), o.str().size() );

wdc = GetDC( _hwnd ); BitBlt( wdc, 0, 0, BMP_WID, BMP_HEI, dc, 0, 0, SRCCOPY ); ReleaseDC( _hwnd, wdc ); _frames++; _frameTime = getTime() - now; if( _frameTime > 1.0f ) _frameTime = 1.0f; 

   }

   void setHWND( HWND hwnd ) { _hwnd = hwnd; }

private: 

   float getTime()
   {

LARGE_INTEGER liTime; QueryPerformanceCounter( &liTime ); return liTime.QuadPart / ( float )_frequency.QuadPart; 

   }
   myBitmap      _bmp;
   HWND          _hwnd;
   float         _start, _fps, _frameTime;
   unsigned int  _frames;
   LARGE_INTEGER _frequency;

}; //-------------------------------------------------------------------------------------------------- class wnd { public: 

   wnd() { _inst = this; }
   int wnd::Run( HINSTANCE hInst )
   {

_hInst = hInst; _hwnd = InitAll(); 

       _noise.setHWND( _hwnd );

ShowWindow( _hwnd, SW_SHOW ); UpdateWindow( _hwnd );

MSG msg; ZeroMemory( &msg, sizeof( msg ) ); while( msg.message != WM_QUIT ) { if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) != 0 ) { TranslateMessage( &msg ); DispatchMessage( &msg ); } else { _noise.mainLoop(); } } return UnregisterClass( "_MY_NOISE_", _hInst ); 

   }

private: 

   static int WINAPI wnd::WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
   {

switch( msg ) { case WM_DESTROY: PostQuitMessage( 0 ); break; default: return DefWindowProc( hWnd, msg, wParam, lParam ); } return 0; 

   }

   HWND InitAll()
   {

WNDCLASSEX wcex; ZeroMemory( &wcex, sizeof( wcex ) ); wcex.cbSize = sizeof( WNDCLASSEX ); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = ( WNDPROC )WndProc; wcex.hInstance = _hInst; wcex.hCursor = LoadCursor( NULL, IDC_ARROW ); wcex.hbrBackground = ( HBRUSH )( COLOR_WINDOW + 1 ); wcex.lpszClassName = "_MY_NOISE_";

RegisterClassEx( &wcex );

RECT rc = { 0, 0, BMP_WID, BMP_HEI }; AdjustWindowRect( &rc, WS_SYSMENU | WS_CAPTION, FALSE ); int w = rc.right - rc.left, h = rc.bottom - rc.top; return CreateWindow( "_MY_NOISE_", ".: Noise image -- PJorente :.", WS_SYSMENU, CW_USEDEFAULT, 0, w, h, NULL, NULL, _hInst, NULL ); 

   }

   static wnd* _inst;
   HINSTANCE   _hInst;
   HWND        _hwnd;
   bmpNoise    _noise;

}; wnd* wnd::_inst = 0; //-------------------------------------------------------------------------------------------------- int APIENTRY _tWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow ) { 

   srand( GetTickCount() ); wnd myWnd;
   return myWnd.Run( hInstance );

} //-------------------------------------------------------------------------------------------------- </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>

Common Lisp

Library: lispbuilder-sdl

noise_sdl.lisp: <lang lisp>;; (require :lispbuilder-sdl)

(defun draw-noise (surface) 

 "draws noise on the surface. Returns the surface"
 (let ((width (sdl:width surface))

(height (sdl:height surface)) (i-white (sdl:map-color sdl:*white* surface)) (i-black (sdl:map-color sdl:*black* surface))) 

   (sdl-base::with-pixel (s (sdl:fp surface))
     (dotimes (h height)

(dotimes (w width) (sdl-base::write-pixel s w h (if (zerop (random 2)) i-white i-black )))))) 

 surface)

(defun draw-fps (surface) 

 "draws fps text-info on surface. Returns surface"
 (sdl:with-surface (s surface)
   (sdl:draw-string-solid-* (format nil "FPS: ~,3f" (sdl:average-fps))

20 20 :surface s :color sdl:*magenta*)))

(defun main () 

 "main function, initializes the library and creates de display window"
 (setf *random-state* (make-random-state))
 (sdl:with-init (SDL:SDL-INIT-VIDEO SDL:SDL-INIT-TIMER)
   (let ((main-window (sdl:window 320 240

:title-caption "noise_sdl.lisp" :bpp 8 :flags (logior SDL:SDL-DOUBLEBUF SDL:SDL-HW-SURFACE) :fps (make-instance 'sdl:fps-unlocked)))) 

     (sdl:initialise-default-font)
     (sdl:with-events ()

(:idle () (sdl:update-display (draw-fps (draw-noise main-window)))) (:video-expose-event () (sdl:update-display)) (:quit-event () T)))))

(main) </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.

Euler Math Toolbox

Currently, Euler Math Toolbox does not have optimized routines to plot matrices with color information. The frames per second are consequently not really good.

<lang Euler Math Toolbox> >function noiseimg () ... $aspect(320,240); clg; $count=0; now=time; $repeat $ plotrgb(intrandom(240,420,2)-1,[0,0,1024,1024]); $ wait(0); $ count=count+1; $ until testkey(); $end; $return count/(time-now); $endfunction >noiseimg 

2.73544353263

</lang>

F#

This implementation includes two methods to update the pixels values. One uses unsafe methods and can do 350 fps on my machine, the second uses safe code to marshal the new values onto the bitmap data and can do 240 fps on the same machine. <lang fsharp>open System.Windows.Forms open System.Drawing open System.Drawing.Imaging open System.Runtime.InteropServices open System.Diagnostics open Microsoft.FSharp.NativeInterop

  1. nowarn "9"

let rnd = System.Random()

// Draw pixels using unsafe native pointer accessor. // This updates the bitmap as fast as possible. let drawbits_fast (size:int) (bits:BitmapData) = 

   let mutable (p:nativeptr<byte>) = NativePtr.ofNativeInt(bits.Scan0)
   for n = 0 to size-1 do
       let c = rnd.Next(2) * 255
       NativePtr.set p 2 (byte c)
       NativePtr.set p 1 (byte c)
       NativePtr.set p 0 (byte c)
       NativePtr.set p 3 (byte 255)
       p <- NativePtr.add p 4

// A reasonably efficient updater using marshalling to copy an array of generated // integers onto the managed bitmap pixel data (see the C# example as well). let drawbits_safe (size:int) (bits:BitmapData) = 

   let data = Array.init size (fun n ->
           let c = rnd.Next(2) * 255
           0xff000000 ||| (c <<< 16) ||| (c <<< 8) ||| c)
   Marshal.Copy(data, 0, bits.Scan0, size) |> ignore

// Create a new bitmap and update using the specified function let make_image (width:int) (height:int) f = 

   let size = width * height
   let bmp = new Bitmap(width, height)
   let bits = bmp.LockBits(Rectangle(0,0,width,height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb)
   f size bits
   bmp.UnlockBits(bits)
   bmp

// Draw 30 frames and record the time and display the frames per second // This function is run asynchronously to avoid blocking the main GUI thread. let drawImage (box:PictureBox) (label:Label) f = async { 

   while true do
       let timer = new Stopwatch()
       timer.Start()
       for frames = 0 to 29 do
           let bmp = make_image 320 240 f
           box.Image <- bmp
       timer.Stop()
       let fps = 30000. / timer.Elapsed.TotalMilliseconds
       label.Text <- sprintf "%.1f fps" fps }

[<System.STAThread>] [<EntryPoint>] let main args = 

   let form = new Form(AutoSize=true,
                       Size=new Size(0,0),
                       Text="image noise demo")
   let panel = new FlowLayoutPanel(AutoSize=true,FlowDirection=FlowDirection.TopDown)
   let box = new PictureBox(AutoSize=true)
   let label = new Label(AutoSize=true, Text="Ready")
   form.FormClosed.Add(fun eventArgs -> Async.CancelDefaultToken()
                                        Application.Exit())
   form.Controls.Add(panel)
   panel.Controls.Add(box)
   panel.Controls.Add(label)
   if args.Length > 0 && args.[0] = "-safe" then
       drawImage box label drawbits_safe |> Async.Start
   else
       drawImage box label drawbits_fast |> Async.Start
   form.Show()
   Application.Run()
   0

</lang>

Factor

~150 FPS

<lang factor>USING: accessors calendar images images.viewer kernel math math.parser models models.arrow random sequences threads timers ui ui.gadgets ui.gadgets.labels ui.gadgets.packs ; IN: rosetta-code.image-noise

bits>pixels ( bits -- bits' pixels )
   [ -1 shift ] [ 1 bitand ] bi 255 * ; inline
?generate-more-bits ( a bits -- a bits' )
   over 32 mod zero? [ drop random-32 ] when ; inline
<random-images-bytes> ( dim -- bytes )
   [ 0 0 ] dip product  [
       ?generate-more-bits
       [ 1 + ] [ bits>pixels ] bi*
   ] B{ } replicate-as 2nip ;
<random-bw-image> ( -- image )
   <image>
       { 320 240 } [ >>dim ] [ <random-images-bytes> >>bitmap ] bi
       L >>component-order
       ubyte-components >>component-type ;

TUPLE: bw-noise-gadget < image-control timers cnt old-cnt fps-model ;

animate-image ( control -- )
   [ 1 + ] change-cnt
   model>> <random-bw-image> swap set-model ;
update-cnt ( gadget -- )
   [ cnt>> ] [ old-cnt<< ] bi ;
fps ( gadget -- fps )
   [ cnt>> ] [ old-cnt>> ] bi - ;
fps-monitor ( gadget -- )
   [ fps ] [ update-cnt ] [ fps-model>> set-model ] tri ;
start-animation ( gadget -- )
   [ [ animate-image ] curry 1 nanoseconds every ] [ timers>> push ] bi ;
start-fps ( gadget -- )
   [ [ fps-monitor ] curry 1 seconds every ] [ timers>> push ] bi ;
setup-timers ( gadget -- )
   [ start-animation ] [ start-fps ] bi ;
stop-animation ( gadget -- )
   timers>> [ [ stop-timer ] each ] [ delete-all ] bi ;

M: bw-noise-gadget graft* [ call-next-method ] [ setup-timers ] bi ;

M: bw-noise-gadget ungraft* [ stop-animation ] [ call-next-method ] bi ;

<bw-noise-gadget> ( -- gadget )
   <random-bw-image> <model> bw-noise-gadget new-image-gadget*
   0 >>cnt 0 >>old-cnt 0 <model> >>fps-model V{ } clone >>timers ;
fps-gadget ( model -- gadget )
   [ number>string ] <arrow> <label-control>
   "FPS: " <label>
   <shelf> swap add-gadget swap add-gadget ;
with-fps ( gadget -- gadget' )
   [ fps-model>> fps-gadget ]
   [ <pile> swap add-gadget swap add-gadget ] bi ;

MAIN-WINDOW: open-noise-window 

   { { title "Black and White noise" } }
   <bw-noise-gadget> with-fps >>gadgets ;</lang>

Go

<lang go>package main

import ( 

   "code.google.com/p/x-go-binding/ui/x11"
   "fmt"
   "image"
   "image/color"
   "image/draw"
   "log"
   "os"
   "time"

)

var randcol = genrandcol()

func genrandcol() <-chan color.Color { 

   c := make(chan color.Color)

   go func() {
       for {
           select {
           case c <- image.Black:
           case c <- image.White:
           }
       }
   }()

   return c

}

func gennoise(screen draw.Image) { 

   for y := 0; y < 240; y++ {
       for x := 0; x < 320; x++ {
           screen.Set(x, y, <-randcol)
       }
   }

}

func fps() chan<- bool { 

   up := make(chan bool)

   go func() {
       var frames int64
       var lasttime time.Time
       var totaltime time.Duration

       for {
           <-up
           frames++
           now := time.Now()
           totaltime += now.Sub(lasttime)
           if totaltime > time.Second {
               fmt.Printf("FPS: %v\n", float64(frames)/totaltime.Seconds())
               frames = 0
               totaltime = 0
           }
           lasttime = now
       }
   }()

   return up

}

func main() { 

   win, err := x11.NewWindow()
   if err != nil {
       fmt.Println(err)
       os.Exit(1)
   }
   defer win.Close()

   go func() {
       upfps := fps()
       screen := win.Screen()

       for {
           gennoise(screen)

           win.FlushImage()

           upfps <- true
       }
   }()

   for _ = range win.EventChan() {
   }

} </lang>

Optimized example

A second example that is somewhat more optimized but maybe more complicated. (~3000fps on a Thinkpad x220 laptop) <lang go>package main

/* Note, the x-go-binding/ui/x11 lib is under development and has as a temp solution 

  set the x window to a static hight and with, you have to manualy set these
  to 240 x 320 in code.google.com/p/x-go-binding/ui/x11/conn.go */

import "code.google.com/p/x-go-binding/ui" import "code.google.com/p/x-go-binding/ui/x11" import "fmt" import "image" import "image/draw" import "log" import "math/rand" import "runtime" import "time"

var bw[65536][64]byte var frameCount = make(chan uint)

func main() { 

  tc := runtime.NumCPU()
  runtime.GOMAXPROCS(tc)

  // Initiate a new x11 screen to print images onto
  win, err := x11.NewWindow()
  if err != nil {
     log.Fatalln(err)
  }
  defer win.Close()
  screen := win.Screen()
  _, ok := screen.(*image.RGBA)
  if !ok {
     log.Fatalln("screen isn't an RGBA image.")
  }

  //Create lookup table for every combination of 16 black/white pixels
  var i, j uint
  for i = 0; i< 65536; i++ {
     for j = 0; j < 16; j++ {
     if i & (1 << j) > 0 {
           bw[i][j*4 + 0] = 0xFF
           bw[i][j*4 + 1] = 0xFF
           bw[i][j*4 + 2] = 0xFF
        }
     }
  }
  // Start fps counter in a new goroutin
  go fps()
  // Start goroutines
  for i := 0; i < tc; i++ {
      go createNoise(win, screen)
  }
  createNoise(win, screen)

}

func createNoise(win ui.Window, screen draw.Image) { 

  var rnd, rnd2 uint64
  var rnd16a, rnd16b, rnd16c, rnd16d uint16
  var img [240 * 320 * 4]byte
  // Populate the image with pixel data
  for {
     for i := 0; i < len(img); i += 256 {
        rnd = uint64(rand.Int63())
        if (i % 63) == 0 {
           rnd2 = uint64(rand.Int63())
        }
        rnd |= rnd2 & 1 << 63 // we have to set the 64'th bit from the rand.Int63() manualy
        rnd16a = uint16( rnd        & 0x000000000000FFFF)
        rnd16b = uint16((rnd >> 16) & 0x000000000000FFFF)
        rnd16c = uint16((rnd >> 32) & 0x000000000000FFFF)
        rnd16d = uint16((rnd >> 48) & 0x000000000000FFFF)
        copy(img[i    :i+ 64], bw[rnd16a][:])
        copy(img[i+ 64:i+128], bw[rnd16b][:])
        copy(img[i+128:i+192], bw[rnd16c][:])
        copy(img[i+192:i+256], bw[rnd16d][:])
        rnd2 = rnd2 >> 1 // rotate to next random bit
     }
     // Copy pixel data to the screen
     copy(screen.(*image.RGBA).Pix, img[:])
     frameCount <- 1
     win.FlushImage()
  }

}

func fps() { 

  last := time.Now()
  var fps uint
  for {
     // wait for a frameCount update
     <-frameCount
     fps++
     if time.Since(last) >= time.Second {
        fmt.Println("fps:", fps)
        fps = 0
        last = time.Now()
     }
  }

} </lang>

Haskell

This uses the GLFW-b bindings for GLFW 3 support: 

cabal install glfw-b

<lang Haskell>import qualified Graphics.Rendering.OpenGL as GL import qualified Graphics.UI.GLFW as GLFW import qualified Foreign as F import qualified System.Random as R

height = 240 width = 320 numbytes = height * width imagesize = GL.Size (fromIntegral width) (fromIntegral height)

main :: IO () main = do 

 isInit <- GLFW.init
 if isInit
 then do
   m <- GLFW.createWindow width height "" Nothing Nothing
   case m of
     Just win -> do
            GLFW.makeContextCurrent m
            GLFW.swapInterval 1
            GLFW.setKeyCallback win $ Just keyCallback
            glLoop win
            GLFW.destroyWindow win
     Nothing  -> return ()
   GLFW.terminate
 else return ()

glLoop :: GLFW.Window -> IO () glLoop win = do 

 foreignPixels <- F.mallocForeignPtrArray numbytes
 F.withForeignPtr foreignPixels
      (\pixels -> do
         let pixelData = GL.PixelData GL.Luminance GL.UnsignedByte pixels
         loop pixelData pixels 0)
   where
     loop pixelData pixels frames = do
              close <- GLFW.windowShouldClose win
              if close
              then return ()
              else do
                  randomizePixels pixels
                  GL.drawPixels imagesize pixelData
                  GLFW.swapBuffers win
                  GLFW.pollEvents
                  time <- GLFW.getTime
                  let fps = 
                          case time of
                            Just t  -> show $ (fromIntegral frames) / t
                            Nothing -> "???"
                  GLFW.setWindowTitle win $ "FPS: " ++ fps
                  loop pixelData pixels $ frames + 1

randomizePixels :: F.Ptr GL.GLubyte -> IO () randomizePixels ptr = iter 0 numbytes 

   where
     iter index range
         | index == range = return ()
         | otherwise = do
       v <- R.randomRIO (0, 1)
       F.pokeElemOff ptr index $ v * 255
       iter (index + 1) range

keyCallback :: GLFW.Window -> GLFW.Key -> Int -> GLFW.KeyState -> 

              GLFW.ModifierKeys -> IO ()

keyCallback win key _ action _ = 

   case key of
     GLFW.Key'Q -> GLFW.setWindowShouldClose win True
     _          -> return ()</lang>

Icon and Unicon

Icon/Unicon provide a portable graphics interface that runs on multiple platforms. The frame rates will be lower than many of the other languages. There are several possible approaches to painting this random noise.

  • Using DrawPoint(c,r) for each pixel base on essentially a coin flip (speed ~= 1x)
  • Using DrawPoint!L on a list L := [c1,r1,c2,r2,...] of foreground pixels to be painted based on a coin flip (speed ~= 2x)
  • Using DrawImage to draw a randomly constructed bi-level images(see pg 157 of the graphics book, speed ~= 10x)

<lang Icon>link printf

procedure main() 

  &window := open("B&W noise 320x240","g","size=320,240","bg=white","fg=black") | 
             stop("Open window failed ")
  runtime := 10 # seconds to run
  sec := &now
  frames := 0
  until (&now - sec) >= runtime do {
     s := "320,#"
     every 1 to 240 & 1 to 320/4 do s ||:= ?"0123456789ABCDEF" 
     DrawImage(0,0,s)
     frames +:= 1
     }
  sec := &now - sec 
  printf("frames=%d, elapsed time=%r, fps=%r\n",frames,sec, frames/real(sec))
  Event()   # wait for any window event
  close(&window)

end</lang>

Library: Icon Programming Library

printf.icn provides a family of print formatting routines

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.

About some of the constants: 160 120 corresponds to a 320 by 240 rendering area (this J version 6 mechanism will be obsolete soon, but I think we should wait for the new code bases stabilize before replacing this code), and the rendering area is not resizable. 53050 was picked because on average half of the pixels will be dark and half of them will be light: We have a black background and 53050 random pixel coordinates (out of 75800 total pixels) being set to being light -- because so many of them will randomly overlap we have on average approximately 50% of each. It would be more efficient to use a pixel shader, pushing the randomizing process into the graphics hardware. But, with this small of a display, efficiency is not really an issue with this approach.

Java

This could be done more concisely, but the version below features the following enhancements:

- Resizable window

- Real-time blurring of noise behind the FPS display

- Cycling through FPS display modes using mouse clicks

- Very fast: 1000+ FPS on a 2.8 GHz Core Duo (with 64-bit JRE). This is capped because the maximum resolution of the timers available is 1 ms <lang java>import java.awt.*; import java.awt.event.*; import java.awt.image.*; import java.util.Arrays; import java.util.Random; import javax.swing.*;

public class ImageNoise { 

   int framecount = 0;
   int fps = 0;
   BufferedImage image;
   Kernel kernel;
   ConvolveOp cop;
   JFrame frame = new JFrame("Java Image Noise");

   JPanel panel = new JPanel() {
       private int show_fps = 0; // 0 = blur + FPS; 1 = FPS only; 2 = neither
       private MouseAdapter ma = new MouseAdapter() {
           @Override
           public void mouseClicked(MouseEvent e) {
               show_fps = (show_fps + 1) % 3;
           }
       };
       {addMouseListener(ma);}

       @Override
       public Dimension getPreferredSize() {
           return new Dimension(320, 240);
       }

       @Override
       @SuppressWarnings("fallthrough")
       public void paintComponent(Graphics g1) {
           Graphics2D g = (Graphics2D) g1;
           drawNoise();
           g.drawImage(image, 0, 0, null);

           switch (show_fps) {
           case 0: 
               // add blur behind FPS
               int xblur = getWidth() - 130, yblur = getHeight() - 32;
               BufferedImage bc = image.getSubimage(xblur, yblur, 115, 32);
               BufferedImage bs = new BufferedImage(bc.getWidth(), bc.getHeight(),
                                                    BufferedImage.TYPE_BYTE_GRAY);
               cop.filter(bc, bs);
               g.drawImage(bs, xblur, yblur , null);
           case 1: 
               // add FPS text; case fallthough is deliberate
               g.setColor(Color.RED);
               g.setFont(new Font("Monospaced", Font.BOLD, 20));
               g.drawString("FPS: " + fps, getWidth() - 120, getHeight() - 10);
           }
           framecount++;
       }
   };
   
   // Timer to trigger update display, with 1 ms delay
   Timer repainter = new Timer(1, new ActionListener() {
       @Override
       public void actionPerformed(ActionEvent e) {
           panel.repaint();
       }
   });
   
   // Timer to check FPS, once per second
   Timer framerateChecker = new Timer(1000, new ActionListener() {
       @Override
       public void actionPerformed(ActionEvent e) {
           fps = framecount;
           framecount = 0;
       }
   });
   
   public ImageNoise() {
       // Intitalize kernel describing blur, and convolve operation based on this
       float[] vals = new float[121];
       Arrays.fill(vals, 1/121f);
       kernel = new Kernel(11, 11, vals);
       cop = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);
       
       // Initialize frame and timers
       frame.add(panel);
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       frame.pack();
       frame.setVisible(true);
       repainter.start();
       framerateChecker.start();
   }

   void drawNoise() {
       int w = panel.getWidth(), h = panel.getHeight();
       
       // Check if our image is null or window has been resized, requiring new image
       if (null == image || image.getWidth() != w || image.getHeight() != h) {
           image = new BufferedImage(w, h, BufferedImage.TYPE_BYTE_GRAY);
       }
       Random rand = new Random();
       int[] data = new int[w * h];
       // Each int has 32 bits so we can use each bit for a different pixel - much faster
       for (int x = 0; x < w * h / 32; x++) {
           int r = rand.nextInt();
           for (int i = 0; i < 32; i++) {
               data[x * 32 + i] = (r & 1) * Integer.MAX_VALUE;
               r >>>= 1;
           }
       }
       // Copy raw data to the image's raster
       image.getRaster().setPixels(0, 0, w, h, data);
   }
   
   public static void main(String[] args) {
       // Invoke GUI on the Event Dispatching Thread
       SwingUtilities.invokeLater(new Runnable() {
           @Override
           public void run() {
               ImageNoise i = new ImageNoise();
           }
       });
   }

}</lang>

JavaScript

jsFiddle Demo

<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);

var index_init = 0; for (var x = 0; x < w; x++) { 

   for (var y = 0; y < h; y++) {
       img.data[index_init + 3] = 255; // alpha
       index_init += 4;
   }

}

function animate() { 

   var index = 0;
   for (var x = 0; x < w; x++) {
       for (var y = 0; y < h; y++) {
           var value = (Math.random() > 0.5) ? 255 : 0;
           img.data[index    ] = value;
           img.data[index + 1] = value;
           img.data[index + 2] = value;
           // alpha channel is constant
           index += 4;
       }
   }

   ctx.putImageData(img, 0, 0);

   frame_count++;
   if (frame_count % 50 == 0) {
       var fps = frame_count / (new Date().getTime() - t1) * 1000;
       window.status = fps.toFixed(2) + " fps";
   }

   setTimeout(animate, 0);

}

animate(); </script> </body></lang> About 59 frames/second on Firefox 4.

Kotlin

Translation of: Java

<lang scala>// version 1.2.10

import java.awt.* import java.awt.event.* import java.awt.image.* import java.util.Random import javax.swing.*

class ImageNoise { 

   var framecount = 0
   var fps = 0
   lateinit var image: BufferedImage
   val kernel: Kernel
   lateinit var cop: ConvolveOp
   val frame = JFrame("Java Image Noise")

   val panel = object : JPanel() {
       private var showFps = 0  // 0 = blur + FPS; 1 = FPS only; 2 = neither
       private val ma = object : MouseAdapter() {
           override fun mouseClicked(e: MouseEvent) {
               showFps = (showFps + 1) % 3
           }
       }

       init {
           addMouseListener(ma)
           preferredSize = Dimension(320, 240)
       }

       override fun paintComponent(g1: Graphics) {
           val g = g1 as Graphics2D
           drawNoise()
           g.drawImage(image, 0, 0, null)
           if (showFps == 0) {
               // add blur behind FPS
               val xblur = width - 130
               val yblur = height - 32
               val bc = image.getSubimage(xblur, yblur, 115, 32)
               val bs = BufferedImage(
                   bc.width, bc.height, BufferedImage.TYPE_BYTE_GRAY
               )
               cop.filter(bc, bs)
               g.drawImage(bs, xblur, yblur, null)
           }
           if (showFps <= 1) {
               // add FPS text
               g.color = Color.RED
               g.font = Font("Monospaced", Font.BOLD, 20)
               g.drawString("FPS: $fps", width - 120, height - 10)
           }
           framecount++
       }
   }

   // Timer to trigger update display, with 1 ms delay
   val repainter = Timer(1, object: ActionListener {
       override fun actionPerformed(e: ActionEvent) = panel.repaint()
   })

   // Timer to check FPS, once per second
   val framerateChecker = Timer(1000, object : ActionListener {
       override fun actionPerformed(e: ActionEvent) {
           fps = framecount
           framecount = 0
       }
   })

   init {
       // Intitalize kernel describing blur, and convolve operation based on this
       val vals = FloatArray(121) { 1.0f / 121.0f }
       kernel = Kernel(11, 11, vals)
       cop = ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null)

       // Initialize frame and timers
       with (frame) {
           add(panel)
           defaultCloseOperation = JFrame.EXIT_ON_CLOSE
           pack()
           isVisible = true
       }
       repainter.start()
       framerateChecker.start()
   }

   fun drawNoise() {
       val w = panel.width
       val h = panel.height

       // Check if our image is initialized or window has been resized,
       // requiring new image
       if (!this::image.isInitialized || image.width != w || image.height != h) {
           image = BufferedImage(w, h, BufferedImage.TYPE_BYTE_GRAY)
       }
       val rand = Random()
       val data = IntArray(w * h)
       // Each int has 32 bits so we can use each bit for a different pixel
       // - much faster
       for (x in 0 until w * h / 32) {
           var r = rand.nextInt()
           for (i in 0..31) {
               data[x * 32 + i] = (r and 1) * Int.MAX_VALUE
               r = r ushr 1
           }
       }
       // Copy raw data to the image's raster
       image.raster.setPixels(0, 0, w, h, data)
   }

}

fun main(args: Array<String>) { 

   // Invoke GUI on the Event Dispatching Thread
   SwingUtilities.invokeLater(object: Runnable {
       override fun run() {
           ImageNoise()
       }
   })

}</lang>

Output:
Similar to Java entry

Liberty BASIC

Generates the random bitmap programmatically, then chops it each time in a different way. <lang lb> WindowWidth =411 w =320 WindowHeight =356 h =240


open "Noise" for graphics_nsb as #w

  1. w "trapclose [quit]"
  2. w "down"

print "Creating BMP header"

'bitmap header, 320x240 pixels 256 colors data 66,77,54,48,1,0,0,0,0,0,54,4,0,0,40,0,0,0,64,1 data 0,0,240,0,0,0,1,0,8,0,0,0,0,0,0,44,1,0,0,0 data 0,0,0,0,0,0,0,1,0,0,0,1,0,0

head$="" for i = 1 to 54 

   read c
   head$=head$+chr$(c)

next

print "Creating BMP grayscale palette" pal$="" for i = 0 to 255 

   pal$ = pal$ _
       + chr$(i) _
       + chr$(i) _
       + chr$(i) _
       + chr$(0)

next

print "Creating BMP random body" 

   'create bitmap body
   body$=""
   for x =1 To w
       l$=""
       for y =1 To h
           l$=l$+chr$((rnd(1)>0.5)*255)
       next
       body$=body$+l$ 
   next

[main] 

   scan
   ts =time$( "ms")
   'randomly "splice" the body: 1111222222-> 2222221111
   splice=int(len(body$)*rnd(1))+1
   body$= mid$(body$,splice+1)+left$(body$,splice)
   'write BMP
   open "noise.bmp" for output as #1
       #1 head$;pal$;
       #1 body$;
   close #1
   'load bmp
   loadbmp "noise", "noise.bmp"
   #w "cls"
   'drawbmp
   #w "drawbmp noise 0 0"

   tf =time$( "ms")
   dt =tf -ts
   if dt = 0 then dt = 1
   print "Framerate per second ="; using( "#.###", 1/(dt/1000)), "Ms per frame =";dt
   goto [main]

[quit] 

   unloadbmp "noise"
   close #w

end </lang>

Maple

  • Note, you will need to insert a plot component to get this to work.

<lang Maple> a:=0; t:=time[real](); while a< 50 do a:=a+1; data := Matrix(`<|>`(`<,>`(Statistics:-Sample(Uniform(0, 1), [1000, 2])), LinearAlgebra:-RandomVector(1000, generator = rand(0 .. 2))));

f := plots:-pointplot(data[NULL .. NULL, 1], data[NULL .. NULL, 2], symbolsize = 20, symbol = solidbox, colorscheme = ["valuesplit", data[NULL .. NULL, 3], [0 = "Black", 1 = "White", 2 = "Grey"]], axes = none); DocumentTools:-SetProperty('Plot0', 'value', plots:-display(f,plots:-textplot([0.5,0.5,sprintf("FPS: %a", (a/(time[real]()-t)))],color=red)), refresh=true);

end do: </lang>

Mathematica / Wolfram Language

<lang Mathematica> time = AbsoluteTime[]; Animate[ 

Column[{Row[{"FPS: ", Round[n/(AbsoluteTime[] - time)]}], 
  RandomImage[1, {320, 240}]}], {n, 1, Infinity, 1}]

</lang>

MAXScript

<lang MAXScript> try destroydialog testRollout catch ()

fn randomBitmap width height = ( local newBmp = bitmap width height

for row = 0 to (height-1) do ( local pixels = for i in 1 to width collect (white*random 0 1) setpixels newBmp [0,row] pixels )

return newBmp )

rollout testRollout "Test" width:320 height:240 ( bitmap image width:320 height:240 pos:[0,0] timer updateTimer interval:1 active:true

on updateTimer tick do ( local startTime = timestamp() image.bitmap = randomBitmap 320 240 local endTime = timestamp() local fps = ((endTime-startTime)/1000.0)*60.0

if mod updatetimer.ticks 10 == 0 do (testRollout.title = ("Test (FPS: "+fps as string+")"))

) )

createdialog testrollout </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
 while true do
   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 ()
 done

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.

Equivalent of the C-OpenGL method.

Perl 6

We'll use minimal mappings for SDL2. The resulting code is embarrassingly slow, but it's better than nothing.

<lang perl6>use NativeCall;

class SDL_Window is repr('CStruct') {} class SDL_Renderer is repr('CStruct') {}

my ($w, $h) = 320, 240; my SDL_Window $window; my SDL_Renderer $renderer;

constant $sdl-lib = 'libSDL2'; constant SDL_INIT_VIDEO = 0x00000020; constant SDL_WINDOWPOS_UNDEFINED_MASK = 0x1FFF0000; constant SDL_WINDOW_SHOWN = 0x00000004;

sub SDL_Init(int32 $flag) returns int32 is native($sdl-lib) {*} sub SDL_Quit() is native($sdl-lib) {*}

sub SDL_CreateWindow(Str $title, int $x, int $y, int $w, int $h, int32 $flag) returns SDL_Window is native($sdl-lib) {*} sub SDL_CreateRenderer(SDL_Window $, int $, int $) returns SDL_Renderer is native($sdl-lib) {*} sub SDL_SetRenderDrawColor(SDL_Renderer $, int $r, int $g, int $b, int $a) returns Int is native($sdl-lib) {*} sub SDL_RenderClear(SDL_Renderer $) returns Int is native($sdl-lib) {*} sub SDL_RenderDrawPoint( SDL_Renderer $, int $x, int $y ) returns Int is native($sdl-lib) {*} sub SDL_RenderPresent(SDL_Renderer $) is native($sdl-lib) {*}

sub render { 

   SDL_SetRenderDrawColor($renderer, 0, 0, 0, 0);
   SDL_RenderClear($renderer);
   SDL_SetRenderDrawColor($renderer, 255, 255, 255, 0);
   loop (my int $i; $i < $w; $i = $i + 1) {
       loop (my int $j; $j < $h; $j = $j + 1) {
           SDL_RenderDrawPoint( $renderer, $i, $j ) if Bool.pick
       }
   }
   SDL_RenderPresent($renderer);

}

SDL_Init(SDL_INIT_VIDEO); $window = SDL_CreateWindow( 

   "some white noise",
   SDL_WINDOWPOS_UNDEFINED_MASK, SDL_WINDOWPOS_UNDEFINED_MASK,
   $w, $h,
   SDL_WINDOW_SHOWN

); $renderer = SDL_CreateRenderer( $window, -1, 1 ); loop { 

   my $then = now;
   render();
   note "{1 / (now - $then)} fps";

} END { SDL_Quit() }</lang>

Pascal

Works with: Free_Pascal
Library: SDL

It is SDL-internally limited to 200 fps. <lang pascal>Program ImageNoise;

uses 

 SDL;

var 

 surface: PSDL_Surface;
 pixel: ^byte;
 frameNumber, totalTime, lastTime, time, i: longint;

begin 

 frameNumber := 0;
 totalTime   := 0;
 lastTime    := 0;
 randomize;
 SDL_Init(SDL_INIT_TIMER or SDL_INIT_VIDEO);
 surface := SDL_SetVideoMode(320, 240, 8, SDL_DOUBLEBUF or SDL_HWSURFACE);
 
 while (true) do
 begin
   pixel := surface^.pixels;
   SDL_LockSurface(surface);
   for i := 1 to (surface^.w * surface^.h) do
   begin
     pixel^ := random(2)*255;
     inc(pixel);
   end;
   SDL_UnlockSurface(surface);
   SDL_Flip(surface);
   inc (frameNumber);

   time := SDL_GetTicks();
   totalTime := totalTime + time - lastTime;
   if (totalTime > 1000) then
   begin
     writeln('FPS: ', frameNumber / (totalTime / 1000.0):5:1);
     frameNumber := 0;
     totalTime := 0;
   end;
   lastTime := time;
 end;

end.</lang>

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)
        Button (java "javax.swing.JButton" T "OK") )
     (java Frame "add" Noise)
     (java Frame "add" "South" Button)
     (java Button "addActionListener"
        (interface "java.awt.event.ActionListener"
           'actionPerformed '((Ev) (bye)) ) )
     (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>

PL/I

<lang>Image_Noise: procedure options (main); /* 3 November 2013 */ 

  declare (start_time, end_time) float (18);
  declare (frame, m, n) fixed binary;

  start_time = secs();
  get (m, n);
  do frame = 1 to 100; /* Generate 100 frames. */
     call display (m, n);
     put skip data (frame);
  end;
  end_time = secs();

  put skip list ('Average FPS =' || fixed(100/(end_time-start_time), 6) );

display: procedure (m, n); 

  declare (m, n) fixed binary;
  declare screen(0:m, 0:n) bit (1);
  declare i fixed binary;
  declare random builtin;

     screen = '0'b; /* clear screen for this frame */
     do i = 0 to m*n*random;
        screen(random*m, random*n) = random > 0.5;
     end;

end display;

end Image_Noise;</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

<lang python>import time import random import Tkinter import Image, ImageTk # PIL libray

class App(object): 

   def __init__(self, size, root):
       self.root = root
       self.root.title("Image Noise Test")

       self.img = Image.new("RGB", size)
       self.label = Tkinter.Label(root)
       self.label.pack()

       self.time = 0.0
       self.frames = 0
       self.size = size
       self.loop()

   def loop(self):
       self.ta = time.time()
       # 13 FPS boost. half integer idea from C#.
       rnd = random.random
       white = (255, 255, 255)
       black = (0, 0, 0)
       npixels = self.size[0] * self.size[1]
       data = [white if rnd() > 0.5 else black for i in xrange(npixels)]
       self.img.putdata(data)
       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)

def main(): 

   root = Tkinter.Tk()
   app = App((320, 240), root)
   root.mainloop()

main()</lang> About 28 FPS max, Python 2.6.6.

Racket

<lang racket>

  1. lang racket

(require 2htdp/image 2htdp/universe)

(define black (color 0 0 0 255)) (define white (color 255 255 255 255))

(define-struct world (last fps))

(define (noise w h) 

 (color-list->bitmap
  (for*/list ([x (in-range w)] [y (in-range h)])
    (if (zero? (random 2)) black white))
  w h))

(define (draw w) 

 (underlay/xy 
  (noise 320 240) 0 0
  (text (number->string (world-fps w)) 64 "Red")))

(define (handle-tick w) 

 (define cm (current-inexact-milliseconds))
 (make-world cm (exact-floor (/ 1000.0 (- cm (world-last w))))))

(big-bang (make-world 1 0) 

         [on-draw draw]
         [on-tick handle-tick (/ 1. 120)])

</lang>

REXX

<lang rexx>/*REXX program times (elapsed) the generation of 100 frames of random black&white image.*/ parse arg sw sd im . /*obtain optional args from the C.L. */ if sw== | sw=="," then sw=320 /*SW specified? No, then use default.*/ if sd== | sd=="," then sd=240 /*SD " " " " " */ if im== | im=="," then im=100 /*IM " " " " " */ call time 'R' /*reset the REXX elapsed (clock) timer.*/ 

             do   im                            /*generate    IM     number of images. */
             call genFrame  sw, sd              /*generate single image of size SW x SD*/
             /*■■■ display frame here ■■■*/     /*do (or don't) display the frame num. */
             end   /*im*/                       /*generate, but don't display the image*/
                                                /*measures  ↓  elapsed time in seconds.*/

say 'The average frames/second: ' format(im/time("E"), , 2) /*show frames/second.*/ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ genFrame: parse arg x,y; @.0= 'ff000000'x /*hex: the color black. */ 

                           @.1= 'ffFFffFF'x                   /* "    "    "    white. */
          $=                                                  /*nullify image string.  */
                 do y;  _=                                    /*nullify an output row. */
                           do x;  ?=random(0,1);  _=_ || @.?  /*color is black │ white.*/
                           end   /*x*/                        /* [↑]  build a whole row*/
                 $=$ || _                                     /*append row to $ string.*/
                 end             /*y*/                        /* [↑]  build the image. */
          return</lang>

Ruby

Library: rubygems
Library: ruby-opengl

<lang ruby>require 'rubygems' require 'gl' require 'glut'

W, H = 320, 240 SIZE = W * H

Glut.glutInit ARGV Glut.glutInitWindowSize W, H

Glut.glutIdleFunc lambda { 

 i = Time.now
 noise = (1..SIZE).map { rand > 0.5 ? 0xFFFFFFFF : 0xFF000000 }.pack("I*")

 Gl.glClear Gl::GL_COLOR_BUFFER_BIT
 Gl.glDrawPixels W, H, Gl::GL_RGBA, Gl::GL_UNSIGNED_BYTE, noise
 Gl.glFlush

 puts 1.0 / (Time.now - i)

}

Glut.glutCreateWindow "noise" Glut.glutMainLoop</lang>

Run BASIC

<lang runbasic>begSec = time$("seconds") graphic #g, 320,240 tics = 320 * 240 for i = 1 to tics 

   x = int((rnd(1) * 320) + 1) 
   y = int((rnd(1) * 240) + 1)
   if int(x mod 2) then  #g "color black ; set "; x; " "; y else #g "color white ; set "; x; " "; y

next i endSec = time$("seconds") totSec = endSec - begSec print "Seconds;";totSec;" Count:";tics;" Tics / sec:";tics/totSec;" fps:";1/totSec render #g

  1. g "flush"</lang>

Scala

This is basically the same as the Java version, except without using BufferedImage. <lang scala> import java.awt.event.{ActionEvent, ActionListener} import swing.{Panel, MainFrame, SimpleSwingApplication} import javax.swing.Timer import java.awt.{Font, Color, Graphics2D, Dimension}

object ImageNoise extends SimpleSwingApplication { 

 var delay_ms = 2
 var framecount = 0
 var fps = 0

 def top = new MainFrame {
   contents = panel
 }

 val panel = new Panel {
   preferredSize = new Dimension(320, 240)

   override def paintComponent(g: Graphics2D) {
     for (x <- 0 to size.width; y <- 0 to size.height) {
       val c = if (math.random > 0.5) Color.BLACK else Color.WHITE
       g.setColor(c)
       g.fillRect(x, y, 1, 1)
     }
     g.setColor(Color.RED)
     g.setFont(new Font("Monospaced", Font.BOLD, 20))
     g.drawString("FPS: " + fps, size.width - 100, size.height - 10)
     framecount += 1
   }
 }

 val repainter = new Timer(delay_ms, new ActionListener {
   def actionPerformed(e: ActionEvent) {
     panel.repaint
   }
 })

 val framerateChecker = new Timer(1000, new ActionListener {
   def actionPerformed(e: ActionEvent) {
     fps = framecount
     framecount = 0
   }
 })

 repainter.start()
 framerateChecker.start()

}</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>

Visual Basic .NET

Some lines in this example are too long (more than 80 characters). Please fix the code if it's possible and remove this message.

Windows Forms Application.

<lang vbnet>Imports System.Drawing.Imaging

Public Class frmSnowExercise 

 Dim bRunning As Boolean = True

 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

   ' Tell windows we want to handle all the painting and that we want it to double buffer
   ' the form's rectangle (Double Buffering removes/reduces flickering).
   SetStyle(ControlStyles.AllPaintingInWmPaint Or ControlStyles.UserPaint Or ControlStyles.OptimizedDoubleBuffer, True)
   UpdateStyles()

   ' Prevent the user from resizing the window. Our draw code is not
   ' setup to recalculate on the fly.
   FormBorderStyle = Windows.Forms.FormBorderStyle.FixedSingle
   MaximizeBox = False

   ' The window size and the client rectangle aren't the same.
   ' To get the proper dimensions for our exercise we need to 
   ' figure out the difference and add it to our 320x240 
   ' requirement.
   Width = 320 + Size.Width - ClientSize.Width
   Height = 240 + Size.Height - ClientSize.Height

   ' Pop the window, bring it to the front and give windows time to 
   ' reflect the changes.
   Show()
   Activate()
   Application.DoEvents()

   ' Hit the loop and keep going until we receive a close request.
   RenderLoop()

   ' We're done. Exit the application.
   Close()

 End Sub

 Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
   ' Close the application when the user hits escape.
   If e.KeyChar = ChrW(Keys.Escape) Then bRunning = False
 End Sub

 Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
   ' We'll cancel the form close request if we're still running so we don't get an error during runtime and set the close request flag.
   e.Cancel = bRunning
   bRunning = False
 End Sub

 Private Sub RenderLoop()

   Const cfPadding As Single = 5.0F

   Dim b As New Bitmap(ClientSize.Width, ClientSize.Width, PixelFormat.Format32bppArgb)
   Dim g As Graphics = Graphics.FromImage(b)
   Dim r As New Random(Now.Millisecond)
   Dim oBMPData As BitmapData = Nothing
   Dim oPixels() As Integer = Nothing
   Dim oBlackWhite() As Integer = {Color.White.ToArgb, Color.Black.ToArgb}
   Dim oStopwatch As New Stopwatch
   Dim fElapsed As Single = 0.0F
   Dim iLoops As Integer = 0
   Dim sFPS As String = "0.0 FPS"
   Dim oFPSSize As SizeF = g.MeasureString(sFPS, Font)
   Dim oFPSBG As RectangleF = New RectangleF(ClientSize.Width - cfPadding - oFPSSize.Width, cfPadding, oFPSSize.Width, oFPSSize.Height)

   ' Get ourselves a nice, clean, black canvas to work with.
   g.Clear(Color.Black)

   ' Prep our bitmap for a read.
   oBMPData = b.LockBits(New Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb)

   ' Allocate sufficient space for the pixel data and 
   ' flash copy it to our array.
   ' We want an integer to hold the color for each pixel in the canvas.
   Array.Resize(oPixels, b.Width * b.Height)
   Runtime.InteropServices.Marshal.Copy(oBMPData.Scan0, oPixels, 0, oPixels.Length)
   b.UnlockBits(oBMPData)

   ' Start looping.
   Do
     ' Find our frame time and add it to the total amount of time 
     ' elapsed since our last FPS update (once per second).
     fElapsed += oStopwatch.ElapsedMilliseconds / 1000.0F
     oStopwatch.Reset()
     oStopwatch.Start()

     ' Adjust the number of loops since the last whole second has elapsed.
     iLoops += 1

     If fElapsed >= 1.0F Then
       ' Since we've now had a whole second elapse
       ' figure the Frames Per Second, 
       ' measure our string,
       ' setup our backing rectangle for the FPS string (so it's clearly visible over the snow)
       ' reset our loop counter 
       ' and our elapsed counter.
       sFPS = (iLoops / fElapsed).ToString("0.0") & " FPS"
       oFPSSize = g.MeasureString(sFPS, Font)
       oFPSBG = New RectangleF(ClientSize.Width - cfPadding - oFPSSize.Width, cfPadding, oFPSSize.Width, oFPSSize.Height)
       fElapsed -= 1.0F ' We don't set this to 0 incase our frame time has gone a bit over 1 second since last update.
       iLoops = 0
     End If

     ' Generate our snow.
     For i As Integer = 0 To oPixels.GetUpperBound(0)
       oPixels(i) = oBlackWhite(r.Next(oBlackWhite.Length))
     Next

     ' Prep the bitmap for an update.
     oBMPData = b.LockBits(New Rectangle(0, 0, b.Width, b.Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb)
     ' Flash copy the new data into our bitmap.
     Runtime.InteropServices.Marshal.Copy(oPixels, 0, oBMPData.Scan0, oPixels.Length)
     b.UnlockBits(oBMPData)

     ' Draw the backing for our FPS display.
     g.FillRectangle(Brushes.Black, oFPSBG)
     ' Draw our FPS.
     g.DrawString(sFPS, Font, Brushes.Yellow, oFPSBG.Left, oFPSBG.Top)

     ' Update the form's background and draw.
     BackgroundImage = b
     Invalidate(ClientRectangle)

     ' Let windows handle some queued events.
     Application.DoEvents()
   Loop While bRunning

 End Sub

End Class</lang> Sample:

XPL0

Measured 102 FPS on a Presario 2100 Notebook Athlon 2500. (The Paint intrinsic could display this image at 327 FPS if Ran(2) was faster.)

<lang XPL0>include c:\cxpl\codes; \intrinsic 'code' declarations int CpuReg, \address of CPU register array (from GetReg) 

   FPS,                        \frames per second, the display's update rate
   Sec,                        \current second of time (from real-time clock)
   SecOld,                     \previous second of time
   X, Y;

[SetVid($101); \set 640x480 graphics CpuReg:= GetReg; \get address of array to access CPU registers FPS:= 0; repeat CpuReg(0):= $0200; \get current time in seconds from BIOS 

       SoftInt($1A);           \software interrupt
       Sec:= CpuReg(3)>>8 & $FF; \register DH contains seconds
       if Sec = SecOld then    \if same as before then
               FPS:= FPS+1     \ bump FPS counter
       else    [SecOld:= Sec;  \otherwise save old seconds and
               CrLf(6);
               IntOut(6, FPS); \ display FPS counter (once per second)
               Text(6, " FPS");
               FPS:= 0;        \ reset FPS counter
               ];
       for Y:= 0, 240-1 do     \fill image with random black and white pixels
           for X:= 0, 320-1 do
               Point(X, Y, if Ran(2) then $F\white\ else 0\black\);

until KeyHit; SetVid(3); \restore normal text mode ]</lang>

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