// Here soars the bird

class PAPERBIRD : public CREATURES
{
private:
double BodyAngle  ;
double WingAngle  ;
double TipAngle [10] ;

void DrawElement(float width, float length)
{

  glBegin (GL_TRIANGLES);
    glVertex3f(0.0,0.0,0.0);
    glVertex3f(0.0,width,length);
    glVertex3f(0.0,0.0,length);
  glEnd ();
} // of DrawElement

void DrawTip (int iteration)
    
{
  if (iteration>0)
  {
    glPushMatrix();
      glRotatef(-2.862, 1.0,0.0,0.0); // Rotate by atan (5/10)
      glRotatef(TipAngle[iteration-1], 0.0,0.0,1.0);
      DrawElement(0.5,10.0);
      DrawTip(iteration-1);
    glPopMatrix ();
  } // of if
}

void DrawWing ()
    
{
  glPushMatrix();
    glRotatef(-11.3, 1.0,0.0,0.0); // Rotate by atan (2/10)
//    glRotatef(MyVar, 0.0,0.0,1.0);
    DrawElement(0.5,10.0);
    DrawTip(10);
  glPopMatrix ();
}

public:

  PAPERBIRD (void)
  {
    BodyAngle = 20.0 ;
    WingAngle = 60.0 ;
  } // of Constructor


int Animate ()
    
{
  enum states
    {
      FINISHED,
      FLAPUP,
      FLAPDOWN,
      FLAPROLL
    };
  
  static int state = FLAPDOWN;
  static float stage = 0.0;  // make this float so not to have to convert all the time!
  int i;
  switch (state)
    {
      case FLAPDOWN:
	{
	  stage++;
          glTranslatef(0.0,stage/100.0*5.0,0.0); // pushup

          for (i=0; i<9; i++)
          {
            TipAngle[i]=0.0;
          } // of for
          TipAngle[9] = stage/100.0*95.0; 
	  if (stage >= 100.0)
	    {
	      state = FLAPROLL;
	      stage = 0.0;
	    } // of for
	} // of case
	break;

      case FLAPROLL:
	{
	  stage++;
          glTranslatef(0.0,(100.0-stage)/100.0*5.0,0.0); // falldown
          for (i=0; i<9; i++)
          {
            TipAngle[i]=(stage/50.0)*30.0;
          } // of for
          TipAngle[9] = 95.0-(95.0-30.0)*stage/50.0;
	  if (stage >= 50.0)
	    {
	      state = FLAPUP;
	      stage = 0.0;
	    } // of for
	} // of case
	break;

      case FLAPUP:
	{
	  stage++;
          glTranslatef(0.0,(50.0-stage)/100.0*5.0,0.0); // falldown
          for (i=0; i<10; i++)
          {
            TipAngle[i]=(1.0-stage/50.0)*30.0;
          } // of for
	  if (stage >= 50.0)
	    {
	      state = FINISHED;
	      stage = 0.0;
	    } // of for
	} // of case
	break;

        case FINISHED:
          state = FLAPDOWN;
          break;

    } // of switch
    return (state);
} // of AnimateBird



void Draw()
    
{
  int i;

  glColor3f (0.2, 0.1, 0.5);
  
  // draw the left wing
  glPushMatrix ();
    glRotatef(BodyAngle,0.0,0.0,1.0);
    DrawElement(2.0,10.0);
    DrawWing();
    // using the symmetry of the bird, we draw exactly the same thing, mirrored!!!
    glScalef(-1.0,1.0,1.0);
    glRotatef(BodyAngle,0.0,0.0,1.0);
    DrawElement(2.0,10.0);
    DrawWing();

  glPopMatrix ();

} // of DrawBird
}; // of Class PAPERBIRD