a new parametric variation: Perspective

2.10/Source/varPerspective.pas

@@ -0,0 +1,144 @@
+unit varPerspective;
+
+interface
+
+uses
+  BaseVariation, XFormMan;
+
+const
+  var_a_name='perspective_angle';
+  var_f_name='perspective_dist';
+
+type
+  TVariationPerspective = class(TBaseVariation)
+  private
+    angle, focus: double;
+    vsin, vf, vfcos: double;
+
+  public
+    constructor Create;
+
+    class function GetName: string; override;
+    class function GetInstance: TBaseVariation; override;
+
+    class function GetNrVariables: integer; override;
+    class 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;
+
+    procedure CalcFunction; override;
+    procedure Prepare; override;
+  end;
+
+implementation
+
+uses
+  math;
+
+// TVariationPerspective
+
+///////////////////////////////////////////////////////////////////////////////
+constructor TVariationPerspective.Create;
+begin
+  angle := random;
+  focus := 2*random + 1;
+end;
+
+procedure TVariationPerspective.Prepare;
+begin
+  vsin := sin(angle*pi/2);
+  vf := vvar * focus;
+  vfcos := vf * cos(angle*pi/2);
+end;
+
+procedure TVariationPerspective.CalcFunction;
+{$if false}
+var
+  t: double;
+begin
+  t := (focus - fty^*vsin);
+  FPx^ := FPx^ + vf * ftx^ / t;
+  FPy^ := FPy^ + vfcos * fty^ / t;
+{$else}
+asm
+    mov     ecx, [eax + FTy]
+    fld     qword ptr [ecx]
+    fld     st
+    fmul    qword ptr [eax + vsin]
+    fsubr   qword ptr [eax + focus]
+    fld     st
+    mov     ecx, [eax + FTx]
+    fdivr   qword ptr [ecx]
+    fmul    qword ptr [eax + vf]
+    mov     ecx, [eax+FPx]
+    fadd    qword ptr [ecx]
+    fstp    qword ptr [ecx]
+    fdivp   st(1), st
+    fmul    qword ptr [eax + vfcos]
+    mov     ecx, [eax+FPy]
+    fadd    qword ptr [ecx]
+    fstp    qword ptr [ecx]
+    fwait
+{$ifend}
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationPerspective.GetInstance: TBaseVariation;
+begin
+  Result := TVariationPerspective.Create;
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationPerspective.GetName: string;
+begin
+  Result := 'perspective';
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationPerspective.GetVariableNameAt(const Index: integer): string;
+begin
+  case Index of
+  0: Result := var_a_name;
+  1: Result := var_f_name;
+  else
+    Result := '';
+  end
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+function TVariationPerspective.SetVariable(const Name: string; var value: double): boolean;
+begin
+  Result := False;
+  if Name = var_a_name then begin
+    angle := Value;
+    Result := True;
+  end else if Name = var_f_name then begin
+    focus := Value;
+    Result := True;
+  end
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationPerspective.GetNrVariables: integer;
+begin
+  Result := 2;
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+function TVariationPerspective.GetVariable(const Name: string; var value: double): boolean;
+begin
+  Result := False;
+  if Name = var_a_name then begin
+    Value := angle;
+    Result := True;
+  end else if Name = var_f_name then begin
+    Value := focus;
+    Result := True;
+  end
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+initialization
+  RegisterVariation(TVariationPerspective);
+end.