Simple Sine Table Generator
lazarus / 39-Graphics

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Gigatron · 2025-05-12 22:52

Hi,

Sometimes if we need to optimise code we need precalculated data
table;
One of my tool based on various sintable generator around www  doing
that.

It can generate signed integer value sine table like on amiga to move
logo or image or text on the screen;
Copy the generated code on your project from memo1Text and move your
image x or y
position taken from sin_data: like move(sin_data[index],100) index is
the value from sin_data table.

Let me share this code with you, be carefull to play with spinedit
values you can encounter data
access error ... hope no !

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Gigatron · 2025-05-13 19:11

A simple demo using sine data table.

Beginner version code :

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1;{$mode objfpc}{$H+} interface uses  Classes, SysUtils, Forms,
Controls, Graphics, Dialogs, StdCtrls, Spin,  ExtCtrls,
BGRAVirtualScreen, BGRABitmap, BGRABitmapTypes, Math; constsin_data
:Array[0..179] of Integer =(0,2,5,7,10,12,15,17,19,22,24,27,29,31,34,3
6,39,41,43,46,48,50,52,55,57,59,61,64,66,68,70,72,74,76,78,80,82,84,86
,88,90,92,94,95,97,99,101,102,104,106,107,109,110,112,113,115,116,117,
119,120,121,122,124,125,126,127,128,129,130,131,132,132,133,134,135,13
5,136,136,137,137,138,138,139,139,139,139,140,140,140,140,140,140,140,
140,140,139,139,139,139,138,138,137,137,136,136,135,135,134,133,132,13
2,131,130,129,128,127,126,125,124,122,121,120,119,117,116,115,113,112,
110,109,107,106,104,102,101,99,97,95,94,92,90,88,86,84,82,80,78,76,74,
72,70,68,66,64,61,59,57,55,52,50,48,46,43,41,39,36,34,31,29,27,24,22,1
9,17,15,12,10,7,5,2); type  { TForm1 }  TForm1 = class(TForm)   
BGRAVirtualScreen1: TBGRAVirtualScreen;    Timer1: TTimer;   
procedure BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);    procedure FormCreate(Sender: TObject);    procedure
Timer1Timer(Sender: TObject);   private   public  end; var  Form1:
TForm1;  txt : Array of Pchar;  s1,s2,s3,s4,s5,s6,s7 :
Integer; implementation {$R *.lfm} { TForm1 } procedure
TForm1.FormCreate(Sender: TObject);begin   SetLength(txt, 1);  txt[0]
:= 'LAZARUS';  SetLength(txt ,Length(txt));  s7 := 0;  s6 := 4;  s5 :=
8;  s4 := 12;  s3 := 16;  s2 := 20;  s1 := 24; end; procedure
TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);begin          Bitmap.FontName := 'Arial';       
 Bitmap.FontHeight := 72;         Bitmap.FontStyle:=[fsBold];        
Bitmap.FillRect(0,0,BGRAVirtualScreen1.Width,BGRAVirtualScreen1.Height
,BGRA(0,0,0));           Bitmap.TextOut(140+60,460 -   sin_data[s1]*3,
   txt[0][0], BGRA(255,255,255));          Bitmap.TextOut(140+120,460
-  sin_data[s2]*3,    txt[0][1], BGRA(255,255,255));         
Bitmap.TextOut(140+180,460 -  sin_data[s3]*3,    txt[0][2],
BGRA(255,255,255));          Bitmap.TextOut(140+240,460 -
 sin_data[s4]*3,    txt[0][3], BGRA(255,255,255));         
Bitmap.TextOut(140+300,460 -  sin_data[s5]*3,    txt[0][4],
BGRA(255,255,255));          Bitmap.TextOut(140+360,460 -
 sin_data[s6]*3,    txt[0][5], BGRA(255,255,255));         
Bitmap.TextOut(140+420,460 -  sin_data[s7]*3,    txt[0][6],
BGRA(255,255,255));           inc(s1,2);inc(s2,2);inc(s3,2);inc(s4,2);
inc(s5,2);inc(s6,2);inc(s7,2);            s1 := s1 mod
Length(sin_data);           s2 := s2 mod Length(sin_data);         
 s3 := s3 mod Length(sin_data);           s4 := s4 mod
Length(sin_data);           s5 := s5 mod Length(sin_data);         
 s6 := s6 mod Length(sin_data);           s7 := s7 mod
Length(sin_data); end; procedure TForm1.Timer1Timer(Sender:
TObject);begin    BGRAVirtualScreen1.RedrawBitmap;end; end.
Optimized Version code in project ;

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1;{$mode objfpc}{$H+}interfaceuses  Classes, SysUtils, Forms,
Controls, Graphics, Dialogs, StdCtrls,  ExtCtrls, BGRAVirtualScreen,
BGRABitmap, BGRABitmapTypes; const  // Sinus table  sin_data:
array[0..179] of Integer =
(0,2,5,7,10,12,15,17,19,22,24,27,29,31,34,36,39                      
               ,41,43,46,48,50,52,55,57,59,61,64,66,68,70,72,74      
                             
 ,76,78,80,82,84,86,88,90,92,94,95,97,99,101,102,104                 
                  
 ,106,107,109,110,112,113,115,116,117,119,120,121,122,124,125,126    
                               
 ,127,128,129,130,131,132,132,133,134,135,135,136,136,137,137,138    
                               
 ,138,139,139,139,139,140,140,140,140,140,140,140,140,140,139,139    
                               
 ,139,139,138,138,137,137,136,136,135,135,134,133,132,132,131,130    
                               
 ,129,128,127,126,125,124,122,121,120,119,117,116,115,113,112,110    
                               
 ,109,107,106,104,102,101,99,97,95,94,92,90,88,86,84,82              
                     
 ,80,78,76,74,72,70,68,66,64,61,59,57,55,52,50,48                    
               
 ,46,43,41,39,36,34,31,29,27,24,22,19,17,15,12,10,7,5,2);  
TEXT_TO_DISPLAY = 'LAZARUS 4.0';  pos_X = 0;  pos_Y = 430;  amp   =
3;  phase = 4;  anim_speed = 2; type  { TForm1 }  TForm1 =
class(TForm)    BGRAVirtualScreen1: TBGRAVirtualScreen;    Timer1:
TTimer;    procedure BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);    procedure FormCreate(Sender: TObject);    procedure
Timer1Timer(Sender: TObject);  private    FPhases: array of Integer; 
public  end; var  Form1: TForm1;  X_Space : Integer; implementation{$R
*.lfm} { TForm1 } procedure TForm1.FormCreate(Sender: TObject);var  i:
Integer;begin   X_Space := 60;  SetLength(FPhases,
Length(TEXT_TO_DISPLAY)); // num letters   for i := 0 to High(FPhases)
do     // downto ?    FPhases[i] := i * phase;  // each letter y pos
pointer in sin tableend; procedure
TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);var  i: Integer;  x, y: Integer;  s: string;begin  
Bitmap.FontName := 'Courier New';  Bitmap.FontHeight := 90; 
Bitmap.FontStyle := [fsBold];   for i := 0 to Length(TEXT_TO_DISPLAY)
- 1 do  begin    x := pos_X + (i + 1) * X_Space;    y := pos_Y -
sin_data[FPhases[i]] * amp;    s := TEXT_TO_DISPLAY[i+1]; // +1   
Bitmap.TextOut(x, y, s, BGRA(255, 255, 255));    Bitmap.TextOut(x-4,
y-4, s, BGRA(255, 0,0));    FPhases[i] := (FPhases[i] + anim_speed)
mod Length(sin_data);  end; end; procedure TForm1.Timer1Timer(Sender:
TObject);begin  BGRAVirtualScreen1.RedrawBitmap;end; end.

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TRon · 2025-05-17 08:28

Quote from: d2010 on May 17, 2025, 06:19:04 amInside my source, my
SinTable have more precision a,at least 4digits.
I'm afraid that somehow there is a misunderstanding about the purpose
of the program made by Gigatron.

It is not about precision but about speed and memory-usage. Perhaps
not that interesting anymore these days but as a comparison how
exactly would you calculate 4 digit-precision on a 8-bit CPU or a CPU
that does not contain an FPU ? And perhaps as equal important, how
does one use that in practice on such CPU ? It serves hardly any
purpose and complicate matters.

If wanted you could use fixed point integers or scaling but that is
not the purpose of the demonstration.

Precalculating an algorithm allows for example to use absolute
coordinates (which saves another addition/shift), allows to pre-apply
ratios and other useful otherwise costly calculations beforehand which
saves cpu-cycles not only because of the calculation already been done
but because that way you only have to take care of indices and/or move
around memory of the pre-calculated data.

On the other hand using this technique also has a turning-point where
pre-calculation has no use anymore as it either will take too much
time to render (all) the values, lost too much precision and/or
requires too much storage space. Newer techniques were developed and
combined in order to improve on these limitations.

As said, the technique as demonstrated does probably not serve much
purpose anymore on modern CPU's but it is nice to see these old
techniques put to use. Though, all that buzz stuff of today is also
just all about some random iteration on some random pre-calculated
data 

fwiw: SinusMaker(tm) is a well-known and perfect example of such tool
that belong(s/ed) to every developers toolkit (back) in the 8-bit era.
The used techniques are still valid though applied on/to/for other
matters these days.

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Gigatron · 2025-05-17 09:21

Quote from: d2010 on May 17, 2025, 06:19:04 amInside my source, my
SinTable have more precision a,at least 4digits.
Can you use myTableCos and myTableSin?
iF you other CircleRounded equations, then use  AcDbEllipse[pc]

Quote from: Gigatron on May 13, 2025, 12:52:48 amHi,

Sometimes if we need to optimise code we need precalculated data
table;
One of my tool based on various sintable generator around www  doing
that.

It can generate signed integer value sine table like on amiga to move
logo or image or text on the screen;
Copy the generated code on your project from memo1Text and move your
image x or y
position taken from sin_data: like move(sin_data[index],100) index is
the value from sin_data table.

Let me share this code with you, be carefull to play with spinedit
values you can encounter data
access error ... hope no !

Hi,

If I had wanted to get out of floating-point values, i would have done
it here, the purpose is explained by @Tron is sufficient. Don't forget
my programs aim for simplicity for those who are new to Pascal and the
Amiga 68000 spirit which has no FPU  When you disassemble a demo on
the Amiga 68000, the sine tables are often signed integers if there is
no 3D.
 @Tron thank you for your clarification on the subject;

Regars Gigatron

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d2010 · 2025-05-17 17:16

I am sorry , at previous message on this Topic, I got many error/s at
Online-broken as Opera.exe.
I am sorry, Please, you here is ..
You search "function
CorrectAngleIfNotReadable(Angle:ads_real):ads_real;"

Can you replace "sin_data" with my-sin-table"?
Please, You quick-watch, and you respond, You got , what you got?
Thanks/thank you/
Best Regards.

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cdbc · 2025-05-17 17:48

Hi
@d2010: STOP TROLLING and wasting peoples time!
Regards Benny