unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls, StdCtrls, ComCtrls, ThdTimer;

type
  TForm1 = class(TForm)
    PaintBox1: TPaintBox;
    Bevel1: TBevel;
    ComboBox1: TComboBox;
    Edit1: TEdit;
    Edit2: TEdit;
    UpDown1: TUpDown;
    UpDown2: TUpDown;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Edit3: TEdit;
    UpDown3: TUpDown;
    Label4: TLabel;
    FXTimer: TThreadedTimer;
    Label5: TLabel;
    PaintBox2: TPaintBox;
    Bevel2: TBevel;
    Edit4: TEdit;
    UpDown4: TUpDown;
  procedure paintOutput;
  procedure createGraph;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure UpDown1Click(Sender: TObject; Button: TUDBtnType);
    procedure UpDown2Click(Sender: TObject; Button: TUDBtnType);
    procedure Edit3Change(Sender: TObject);
    procedure FXTimerTimer(Sender: TObject);
    procedure UpDown4Click(Sender: TObject; Button: TUDBtnType);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  channels: byte;                    // no. of output channels
  output: array[0..200] of byte;     // output data
  ringbuffer: array[0..200] of byte; // function is stored in
  offset: byte;                      // offset of function to 0
  amplitude: byte;                   // amplitude of function
  phase: byte;                        // space between output cells in ringbuffer
  readPos: byte;                     // position of read pointer
  GraphBuf: TBitmap;                 // Back-Buffer

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
var i: integer;
begin
GraphBuf := TBitmap.create;
  GraphBuf.Width := 200;
  GraphBuf.height := 100;
 bitblt(GraphBuf.canvas.handle,0,0,205,145,0,0,0,blackness); // kill back-buffer

for i:=0 to 200 do
    begin
    ringbuffer[i]:=0;
    output[i]:=0;
    end;
amplitude:=127;
offset:=127;
phase:=1;
readPos:=0;
channels:=10;
end;

// select function
procedure TForm1.ComboBox1Change(Sender: TObject);
var i, buffer: integer;
begin
case ComboBox1.ItemIndex of

0:   // sine
     begin
     for i:=0 to 200 do
        begin
        buffer:= offset + round(amplitude *sin(i *PI/100));
        if buffer < 0 then buffer:=0;
        if buffer > 255 then buffer:= 255;
        ringbuffer[i]:= buffer;
        end;
     end;
end;
createGraph;
end;

// offset
procedure TForm1.UpDown1Click(Sender: TObject; Button: TUDBtnType);
begin
offset:= UpDown1.Position;
ComboBox1Change(Form1);
end;

// amplitude
procedure TForm1.UpDown2Click(Sender: TObject; Button: TUDBtnType);
begin
amplitude:= UpDown2.Position;
ComboBox1Change(Form1);
end;

// phase
procedure TForm1.Edit3Change(Sender: TObject);
begin
phase:= UpDown3.Position;
if phase * channels > 200 then
   begin
   phase:= 200 div channels;
   UpDown3.Position:= phase;
   end;
end;

// set channels
procedure TForm1.UpDown4Click(Sender: TObject; Button: TUDBtnType);
begin
channels:= UpDown4.Position;
end;

// generate output
procedure TForm1.FXTimerTimer(Sender: TObject);
var i, buffer: integer;
begin
readPos:=readPos +1;
if readPos > 200 then readPos:=0;
label5.caption:= inttostr(readPos);
for i:=0 to channels do
    begin
    buffer:= readPos +phase *i;
    if buffer > 200 then buffer:= buffer -200;
    output[i]:= ringbuffer[buffer];
    end;
paintOutput;
end;

// paint Outut Bar
procedure TForm1.paintOutput;
var i, lang, inkrement: integer;
begin
// bar
with PaintBox1.Canvas do
     begin
     lang:=0;
     inkrement:= 300 div channels;
     for i:=0 to channels do
         begin
         Brush.Color:= RGB(0, Output[i], 0);
         FillRect(Rect(1,lang, 24, lang +inkrement));
         lang:= lang +inkrement;
         end;
     end;
// graph
bitblt(PaintBox2.Canvas.Handle,0,0,200,100,GraphBuf.canvas.handle,0,0,srccopy);
with PaintBox2.canvas do
     begin
     Pen.Color:= clRed;
     for i:=0 to channels do
         begin
         inkrement:= readPos +phase *i;
         if inkrement > 200 then inkrement:= inkrement -200;
         MoveTo(inkrement, 200);
         LineTo(inkrement,0);
         end;
     end;
end;

procedure TForm1.createGraph;
var i: integer;
begin
with GraphBuf.Canvas do
     begin
     Brush.Color:= clBlack;
     Pen.Color:= clGreen;
     Rectangle(0,0,200,100);
     MoveTo(0,200);
     for i:=0 to 200 do
         begin
         LineTo(i, 92-(ringbuffer[i]div 3));
         end;
     end;
bitblt(PaintBox2.Canvas.Handle,0,0,200,100,GraphBuf.canvas.handle,0,0,srccopy);
end;












end.