new variation - quite good (and fast) pseudo-spherical distortion

2.10/Source/VarBubble.pas

@@ -0,0 +1,84 @@
+unit VarBubble;
+
+interface
+
+uses
+  BaseVariation, XFormMan;
+
+type
+  TVariationBubble = class(TBaseVariation)
+  public
+    class function GetName: string; override;
+    class function GetInstance: TBaseVariation; override;
+
+    procedure CalcFunction; override;
+  end;
+
+implementation
+
+uses
+  math;
+
+// TVariationBubble - a pseudo-spherical distortion
+
+///////////////////////////////////////////////////////////////////////////////
+procedure TVariationBubble.CalcFunction;
+{$if false}
+var
+  r: double;
+begin
+  r := vvar / ((sqr(FTx^) + sqr(FTy^))/4 + 1);
+
+  FPx^ := FPx^ + r * FTx^;
+  FPy^ := FPy^ + r * FTy^;
+{$else}
+asm
+    mov     ecx, [eax+FTy]
+    fld     qword ptr [ecx]
+    mov     ecx, [eax+FTx]
+    fld     qword ptr [ecx]
+
+    fld     st(1)
+    fmul    st, st
+    fld     st(1)
+    fmul    st, st
+    fadd
+
+    fld1
+    fadd    st, st
+    fadd    st, st
+    fdivp   st(1), st
+    fld1
+    fadd
+    fdivr    qword ptr [eax+vvar]
+
+    fmul    st(2), st
+    fmulp
+    mov     ecx, [eax+FPx]
+    fadd    qword ptr [ecx]
+    fstp    qword ptr [ecx]
+
+    mov     ecx, [eax+FPy]
+    fadd    qword ptr [ecx]
+    fstp    qword ptr [ecx]
+
+    fwait
+{$ifend}
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationBubble.GetInstance: TBaseVariation;
+begin
+  Result := TVariationBubble.Create;
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+class function TVariationBubble.GetName: string;
+begin
+  Result := 'bubble';
+end;
+
+///////////////////////////////////////////////////////////////////////////////
+initialization
+  RegisterVariation(TVariationBubble);
+end.