FTGL de Orientation

　FTGLがオリエンテーションとフォント・アライメントに対応していなかったので、ＸＹ平面上ながら書いてみました。

#define FT_V_MASK    0xFF00
#define FT_V_TOP     0x0100
#define FT_V_CENTER  0x0200
#define FT_V_BOTTOM  0x0300

#define FT_H_MASK    0x00FF
#define FT_H_LEFT    0x0001
#define FT_H_CENTER  0x0002
#define FT_H_RIGHT   0x0003

#define PI 3.14159265

template <typename STR, typename FONT>
void AlignedRender( 
  FONT& font, 
  STR* text, int text_len, 
  FTPoint pos,   //!< position
  FTPoint spc,   //!< Spacing
  double ang,    //!< Orientation angle
  int alignment  //!< Font alignment
) {
  FTBBox box = font.BBox( text, text_len );
  FTPoint sp = box.Upper() - box.Lower();
  double offset_x = double();
  double offset_y = double();
  switch( (alignment & FT_V_MASK) ) {
  case FT_V_TOP:     offset_y = sp.Y();        break;
  case FT_V_CENTER:  offset_y = sp.Y() / 2.0;  break;
  case FT_V_BOTTOM:
  default: {}
  }
  switch( (alignment & FT_H_MASK) ) {
  case FT_H_RIGHT:   offset_x = sp.X();        break;
  case FT_H_CENTER:  offset_x = sp.X() / 2.0;  break;
  case FT_H_LEFT:
  default: {}
  }
  double cpar = std::cos( ang / 180.0 * PI );
  double spar = std::sin( ang / 180.0 * PI );
  double xx = cpar * offset_x - spar * offset_y;
  double yy = spar * offset_x + cpar * offset_y;
  offset_x  = pos.X() - xx;
  offset_y  = pos.Y() - yy;
  glTranslatef( offset_x, offset_y, 0.0 );
  glRotatef( ang, 0.0, 0.0, 1.0 );
  font.Render( text, text_len );
  glRotatef( - ang, 0.0, 0.0, 1.0 );
  glTranslatef( - offset_x, - offset_y, 0.0 );
}