Peter de Jong Attractor: Bgrabmp Colouring Help Needed ?

[Boleeman]

I made a Lazarus program that creates Peter de Jong Attractors.

I am trying to get a smooth high coloured rainbow effect like at
https://richardrosenman.com/shop/peter-de-jong-attractor/


I used a TBgrabmap for the rendering but have been struggling to get a high coloured rendering."

Up to version 4, after making a basic rendering and then extending it.

[Thaddy]

Wow. Made me think to apply it to audio:

Code: Pascal  [Select][+][-]

1. unit PeterDeJongAttractor;
2. {$mode objfpc}
3. interface
4.  
5. uses
6.   Math, Types;
7. type
8.   TDoublePoint = record
9.     X, Y: Double;
10.     constructor Create(AX, AY: Double);
11.   end;
12.  
13. constructor TDoublePoint.Create(AX, AY: Double);
14. begin
15.   X := AX;
16.   Y := AY;
17. end;
18.  
19.   TPDJAttractor = class
20.   private
21.     Fx, Fy: Double;
22.     FParamA, FParamB, FParamC, FParamD: Double;
23.   public
24.     constructor Create(a, b, c, d: Double);
25.     /// Returns the next point in the attractor sequence
26.     function Iterate: TDoublePoint;inline;
27.     /// Reset to initial state (optional)
28.     procedure Reset;inline;
29.   end;
30.  
31. implementation
32.  
33. constructor TPDJAttractor.Create(a, b, c, d: Double);
34. begin
35.   FParamA := a;
36.   FParamB := b;
37.   FParamC := c;
38.   FParamD := d;
39.   Fx := 0;
40.   Fy := 0;
41. end;
42.  
43. function TPDJAttractor.Iterate: TDoublePoint;
44. var
45.   newX, newY: Double;
46. begin
47.   newX := Sin(FParamA * Fy) - Cos(FParamB * Fx);
48.   newY := Sin(FParamC * Fx) - Cos(FParamD * Fy);
49.   Fx := newX;
50.   Fy := newY;
51.   Result := TDoublePoint.Create(newX, newY);
52. end;
53.  
54. procedure TPDJAttractor.Reset;
55. begin
56.   Fx := 0;
57.   Fy := 0;
58. end;
59.  
60. end.

Then:

Code: Pascal  [Select][+][-]

1. procedure TMyVSTModule.ProcessAudioBlock(Buffer: PSingle; SampleCount: Integer);
2. var
3.   i: Integer;
4.   AttractorPoint: TDoublePoint;
5.   ModulationValue: Single;
6. begin
7.   for i := 0 to SampleCount - 1 do
8.   begin
9.     // Retrieve the current attractor values (could be at a slower modulation rate)
10.     AttractorPoint := FMyAttractor.Iterate;
11.     // Map the output to a useful modulation range. For example, normalize and scale:
12.     ModulationValue := (CSng(AttractorPoint.X) + 2) / 4; // maps from [-2,2] to [0,1]
13.    
14.     // Use ModulationValue to influence a parameter in your DSP code:
15.     // For example, adjust oscillator frequency, filter cutoff, etc.
16.     ApplyModulationToYourDSP(ModulationValue);
17.  
18.     // Continue processing audio...
19.     Buffer[i] := ProcessSample(Buffer[i]);
20.   end;
21. end;

I think I have a VST to write....This is just a scetch.
You can probably also use this simple unit for your graphics purpose.

[Boleeman]

Wondered how that audio version would sound ?


There are lots of graphic versions about , written in other languages but never thought of audio versions.