// ------------------------------------------------------------------------
  // 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: isometricprojection.cppm
  // 
  // Description: Choosing the view direction to get an isometric projection of cube(s)
  // --------------
  
  include <stdafx.h>
  
  include <stdio.h>
  include <stdlib.h>
  include <glut.h>
  include <math.h>
  
  using namespace std;
  
  define M_PI 3.14159265
  
  double theta = 45.0, phi=45.0;
  double pos=4.0;
  
  void display(void) {
   float xeye,yeye,zeye;
  
    glClearColor(1,1,1,1);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluPerspective(54,1.0,1.0,50.0);
  
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   
    xeye = pos * cos(phi*M_PI/180.0) * cos(theta*M_PI/180.0);
    yeye = pos * cos(phi*M_PI/180.0) * sin(theta*M_PI/180.0);
    zeye = pos * sin(phi*M_PI/180.0);
    
    gluLookAt(xeye,yeye,zeye,   
              0.0,0.0,0.0,   
              0.0,0.0,1.0);   
    
  
  // Draw principal axes
   glColor3f(0.5,0.5,0.5);
   glLineWidth(5.0);
   glBegin(GL_LINES);
    glVertex3f(0.0,0.0,0.0);
    glVertex3f(3,0.0,0.0);
    glVertex3f(0.0,0.0,0.0);
    glVertex3f(0.0,3,0.0);
    glVertex3f(0.0,0.0,0.0);
    glVertex3f(0.0,0.0,3);
   glEnd();
  
   // DrawCube
  
  glColor3f(0,0,0);
  glLineWidth(2.0);
  glutWireCube(1.0);
  
  glPushMatrix();
  glTranslatef(0,-1,0);
  glColor3f(0,0,1);
  glutWireCube(1.0);
  glPopMatrix();
  
  glPushMatrix();
  glTranslatef(-1,0,0);
  glColor3f(1,0,0);
  glutWireCube(1.0);
  glPopMatrix();
  
  glPushMatrix();
  glTranslatef(0,0,-1);
  glColor3f(0,1,0);
  glutWireCube(1.0);
  glPopMatrix();
  
   glFlush();
   glutSwapBuffers();
  }
  
  void keyboard(unsigned char key,int x,int y) 
  {
   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_DOUBLE | GLUT_RGB | GLUT_DEPTH);
      glutInitWindowSize(1024, 1024);
      glutCreateWindow("Isometric Projection");
      glutDisplayFunc(display);
      glutKeyboardFunc(keyboard);
          glEnable(GL_DEPTH_TEST); 
      glutMainLoop();
          return 0;
  }