// ------------------------------------------------------------------------
  // This program is complementary material for the book:
  //
  // Frank Nielsen
  //
  // Visual Computing: Geometry, Graphics, and Vision
  //
  // ISBN: 1-58450-427-7
  //
  // Charles River Media, Inc.
  //
  //
  // All programs are available at www.charlesriver.com/visualcomputing/
  //
  // You may use this program for ACADEMIC and PERSONAL purposes ONLY. 
  //
  //
  // The use of this program in a commercial product requires EXPLICITLY
  // written permission from the author. The author is NOT responsible or 
  // liable for damage or loss that may be caused by the use of this program. 
  //
  // Copyright (c) 2005. Frank Nielsen. All rights reserved.
  // ------------------------------------------------------------------------
   
  // ------------------------------------------------------------------------
  // File: radialdistortion.cpp
  // 
  // Description: A simple interactive interface for visualizing the radial
  // distortion effects. Use only one coefficient: kappa1 (Tsai model)
  // ------------------------------------------------------------------------
  
  include <stdafx.h>
  
  include <windows.h>
  include <math.h>
  include <GL/gl.h>
  include <GL/glut.h>
  
  define M_PI 3.14159265
  
  using namespace std;
  
  define W 800
  define H 800
  
  double kappa1=0.0, aspecty=1.0;
  
  double dkappa1=0.0001;
  double daspecty=0.1;
  
  void DrawCircle(double x, double y, double r)
  {
  int k;
  double xd, yd, rd, angle;
  double xi, yi, ri;
  
  glBegin(GL_LINE_LOOP);
  
  for(k=0;k<100;k++)
  {
  angle=2.0*M_PI*k/100.0;
  
  // from distorted to ideal
  xd=x+r*cos(angle);
  yd=y+r*sin(angle);
  rd=r;
  
  ri=rd*(1+kappa1*rd*rd);
  
  xi=x+ri*cos(angle);
  yi=y+ri*sin(angle);
  
  glVertex2f(xi,yi);
  
  }
  glEnd();
  
  }
  
  void display(void)
  {
  char buffer[256];
  int i,j;
  
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
    glColor3f (0, 0, 0);
  
    glBegin(GL_LINES);
    for(i=0;i<H;i+=50)
    {
          glVertex2f(0,i);
          glVertex2f(W,i);
    }
  
    for(i=0;i<W;i+=50)
    {
          glVertex2f(i,0);
          glVertex2f(i,H);
    }
            glEnd();
  
            glColor3f(0,0,1);
            for(int k=0;k<W;k+=5)
                    DrawCircle(W/2,H/2,k);
  
            glColor3f (0, 0, 0);
   glRasterPos2f(50,30);
     sprintf(buffer,"Radial distortions. kappa1=\%e",kappa1);
     for(int i=0;buffer[i]!=0;i++)
     glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, buffer[i]);
  
     glRasterPos2f(50,H-30);
     sprintf(buffer,"Press  '<'/'>' for kappa1");
     for(int i=0;buffer[i]!=0;i++)
     glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, buffer[i]);
  
   
  
   glFlush();
   glutSwapBuffers();
  
  }
  
  void keyboard(unsigned char key, int x, int y)
  {
    if (key=='q') exit(0);
  
    // aspect y
    if (key==43) {aspecty+=daspecty;}
  
    if (key==45) {aspecty-=daspecty;}
  
    // kappa
    if (key==62) {kappa1+=dkappa1;}
  
    if (key==60) {kappa1-=dkappa1;}
  
    glutPostRedisplay();
  }
  
  int _tmain(int argc, _TCHAR* argv[])
  {
  cout<<"Visual Computing: Geometry, Graphics, and Vision (ISBN:1-58450-427-7)"<<endl;
  cout<<"Demo program\n\n"<<endl;
  
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); 
    glutInitWindowSize(W,H);
    glutCreateWindow("Radial distortions");
  
    glutDisplayFunc(display);
    glutKeyboardFunc(keyboard);
  
     glOrtho (0.0, W, 0.0, H, -1.0, 1.0);
    glClearColor(1.0, 1.0, 1.0, 0.0);
    glutMainLoop();
    return 0;
  }