Demo Scene BGRA Circle Demo
lazarus / 39-Graphics

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Gigatron · 2024-05-27 18:40

Hi,

This is my fast coding from zero to 100 in less than 20 minutes ;
Learning BGRA on progress;

State of the art is demo on Amiga made by Spaceballs there is a nice
fx on begining with the circles ;
This code (60 lines ) reproduce this fx not yet perfect with math ;

https://www.youtube.com/watch?v=5aXsrYI3S6g&t=37s

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, ExtCtrls,  BGRAVirtualScreen, BGRABitmap,
BGRABitmapTypes; type   { TForm1 }   TForm1 = class(TForm)   
BGRAVirtualScreen1: TBGRAVirtualScreen;    Timer1: TTimer;   
procedure BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);    procedure Timer1Timer(Sender: TObject);  private  
public   end; var  Form1: TForm1;  angle : single; implementation {$R
*.lfm} { TForm1 } procedure TForm1.Timer1Timer(Sender: TObject);begin 
    BGRAVirtualScreen1.RedrawBitmap;end; procedure
TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);var  i : integer;begin      i:=0;      for i:=0 to 29 do 
    begin       
Bitmap.Ellipse(320+80*sin(-angle),220+40*cos(-angle),20+i*20,
20+i*20,BGRA($09,$7E,$00),10 ,dmSet);       end;       for i:=0 to 33
do      begin       
Bitmap.Ellipse(580,220+140*cos(angle*1.5),20+i*20,
20+i*20,BGRA($7d,$00,$4e),10 ,dmSet); // This is now correct !     
end;     angle := angle + PI/180;        end;end.

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circular · 2024-05-28 15:52

You can try dmXor instead of dmSet to combine the colors when they
intersect.

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Gigatron · 2024-05-28 16:45

Quote from: circular on May 28, 2024, 05:52:21 pmYou can try dmXor
instead of dmSet to combine the colors when they intersect.
Nice , thank you Circular ;
Just added draw mode Xor and it's working well; you can now play with
different parameters of circles ;

* Edit a bit optimized code V0.6 :

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, ExtCtrls, StdCtrls,  Spin,
BGRAVirtualScreen, BGRABitmap, BGRABitmapTypes; type   { TForm1 }  
TForm1 = class(TForm)    BGRAVirtualScreen1: TBGRAVirtualScreen;   
ColorButton1: TColorButton;    ColorButton2: TColorButton;   
ComboBox1: TComboBox;    GroupBox1: TGroupBox;    SpinEdit1:
TSpinEdit;    SpinEdit2: TSpinEdit;    Timer1: TTimer;    procedure
BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap: TBGRABitmap);   
procedure ComboBox1Change(Sender: TObject);    procedure
FormCreate(Sender: TObject);    procedure Timer1Timer(Sender:
TObject);  private  public  end; var  Form1: TForm1;  angle : single; 
space,wdt,dmode : integer; implementation {$R *.lfm} { TForm1
} procedure TForm1.FormCreate(Sender: TObject);begin  space := 12; 
wdt   := 24;  dmode :=  0;    // draw mode !end; procedure
TForm1.Timer1Timer(Sender: TObject);begin      angle := angle +
PI/180;      space := SpinEdit1.Value;      wdt   := SpinEdit2.Value; 
    BGRAVirtualScreen1.RedrawBitmap;end; procedure
TForm1.BGRAVirtualScreen1Redraw(Sender: TObject; Bitmap:
TBGRABitmap);var  i : integer;  drawMode: TDrawMode;  sinAngle,
cosAngle, cosAngle2: single;  col1, col2: TColor;begin       if
dmode=0 then drawMode:=  dmSet      else      drawMode := dmXor;     
sinAngle := sin(angle * 0.6);      cosAngle := cos(-angle * 2);     
cosAngle2 := cos(angle * 1.5);      col1 :=
TColor(ColorButton2.ButtonColor);      col2 :=
TColor(ColorButton1.ButtonColor);      for i:=0 to 34 do      begin  
    Bitmap.Ellipse(320+300*sinAngle,220+120*cosAngle,1+i*wdt,
1+i*wdt,col1,space ,drawMode);      end;      for i:=0 to 34 do     
begin        Bitmap.Ellipse(560,220+140*cosAngle2,1+i*wdt,
1+i*wdt,col2,space ,drawMode);      end;end; procedure
TForm1.ComboBox1Change(Sender: TObject);begin      dmode :=
ComboBox1.ItemIndex;end; end.

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circular · 2024-05-28 21:36

Love it

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Gigatron · 2024-05-28 22:09

Thank you,

All this is becoming reality thanks to your work on the BGRA
component, and the Lazarus Fpc team;