{ 
	Apophysis AV "Phoenix Edition" Copyright (C) 2021 Alice V. Koryagina
	"Chaotica"	Copyright (C) 2019 Glare Technologies Limited 
}

unit varTanhSpiral;

interface
uses
  BaseVariation, XFormMan;

type
  TVariationTanhSpiral = class(TBaseVariation)
  private
    ta: double;
  public
    constructor Create;

    class function GetName: string; override;
    class function GetInstance: TBaseVariation; override;

    function GetNrVariables: integer; override;
    function GetVariableNameAt(const Index: integer): string; override;

    function SetVariable(const Name: string; var value: double): boolean; override;
    function GetVariable(const Name: string; var value: double): boolean; override;
    function ResetVariable(const Name: string): boolean; override;

    procedure CalcFunction; override;
  end;

implementation

uses
  Math;
  
////////////////////////

procedure TVariationTanhSpiral.CalcFunction;
var  
	t, aux, sn, cn, snh, cnh: double;
begin                    
  t := (random - 0.5) * PI2;
 
  SinCos(ta * t, sn, cn);
  SinhCosh(t, snh, cnh);
  
  aux := (cn + cnh); 
  if aux = 0 then  aux := 1e-20;
  aux := vvar / aux;
  
  FPx^ := FPx^ + snh * aux;
  FPy^ := FPy^ + sn * aux;
end;

constructor TVariationTanhSpiral.Create;
begin
  inherited Create;
  ta := 4;
end;

class function TVariationTanhSpiral.GetInstance: TBaseVariation;
begin
   Result := TVariationTanhSpiral.Create;
end;

class function TVariationTanhSpiral.GetName: string;
begin
   Result := 'tanh_spiral';
end;

function TVariationTanhSpiral.GetNrVariables: integer;
begin
  Result := 1;
end;

function TVariationTanhSpiral.GetVariableNameAt(const Index: integer): string;
begin
  case Index Of
    0: Result := 'tanh_spiral_a';
  else
    Result := '';
  end;
end;

function TVariationTanhSpiral.GetVariable(const Name: string; var value: double): boolean;
begin
 Result := False;
  if Name = 'tanh_spiral_a' then begin
    Value := ta;
    Result := True;
  end;
end;

function TVariationTanhSpiral.SetVariable(const Name: string; var value: double): boolean;
begin
 Result := False;
  if Name = 'tanh_spiral_a' then begin
    ta := Value;
    Result := True;
  end;
end;

function TVariationTanhSpiral.ResetVariable(const Name: string): boolean;
begin
 Result := False;
  if Name = 'tanh_spiral_a' then begin
    ta := 4;
    Result := True;
  end;
end;

//////////////////////////////
initialization
  RegisterVariation(TVariationClassLoader.Create(TVariationTanhSpiral), false, false);

end.