Interface of SDL_Complex

const
{$IFDEF PAIDVERS}
  SDLVersionInfo = 'complex_r1200_full';
  IsLightEd = false;
{$ELSE}
  SDLVersionInfo = 'complex_r1200_lighted';
  IsLightEd = true;
{$ENDIF}
  Release = 1200;

type
  ESDLComplexError = class(ESDLError);     { exception type to indicate errors }

  TComplex = record                  // z = re + i * im
               re : extended;
               im : extended;
             end;

  TComplexPolar = record             // z = r*(cos(phi)+i*sin(phi))
                    r   : extended;  // phi = -Pi .... +Pi
                    phi : extended;
                  end;

const
  COMPLEX_0 : TComplex = (re:0; im:0);
  COMPLEX_1 : TComplex = (re:1; im:0);

var
  CpxNearZero : extended;                  { smallest non-zero positive number }

  function ConvertRectToPolar
               (const z : TComplex)       { rectangular form of complex number }
                        : TComplexPolar;                          { polar form }
  function ConvertPolarToRect
               (const z : TComplexPolar)        { polar form of complex number }
                        : TComplex;                         { rectangular form }
  function Cpx
      (const real, imag : extended)    { real and imag. part of complex number }
                        : TComplex;                           { complex number }
  function CpxAbs
                (const z: TComplex)                           { complex number }
                        : extended;                      { absolute value of z }
  function CpxAbsSqr
                (const z: TComplex)                           { complex number }
                        : extended;            { square of absolute value of z }
  function CpxAdd
          (const z1, z2 : TComplex)             { complex numbers to add z1+z2 }
                        : TComplex;                              { complex sum }
  function CpxConj
                (const z: TComplex)                           { complex number }
                        : TComplex;               { complex conjugate value z* }
  function CpxDiv
          (const z1, z2 : TComplex)          { complex numbers to divide z1/z2 }
                        : TComplex;                         { complex quotient }
  function CpxIsEqual
                (z1, z2 : TComplex)               { complex numbers to compare }
                        : boolean;                             { TRUE if equal }
  function CpxIsNearEqual
                (z1, z2 : TComplex)               { complex numbers to compare }
                        : boolean;                      { TRUE if nearly equal }
  function CpxIsZero
                     (z : TComplex)                { complex number test for 0 }
                        : boolean;                              { TRUE if zero }
  function CpxMult
          (const z1, z2 : TComplex)        { complex numbers to multiply z1*z2 }
                        : TComplex;                          { complex product }
  function CpxNeg
                (const z: TComplex)                           { complex number }
                        : TComplex;               { negative complex number -z }
  function CpxSub
          (const z1, z2 : TComplex)        { complex numbers to subtract z1-z2 }
                        : TComplex;                       { complex difference }