/************************************************************
 * File: house.cc
 * Author: C.Yap
 * Date: Sep 23, 2001.
 * Synopsis:  
 *	OpenGL program for lecture 2
 * 	Illustrates the use of display lists in GLUT.
 *	
 ************************************************************/

#include <iostream.h>	// needed for use of cout
#include <math.h>	// needed for math functions exp(x), etc

// #include <windows.h>
#include <GL/glut.h>

/////////////////////////////////////////////////////////////
// constants
/////////////////////////////////////////////////////////////
int screenWidth = 640;
int screenHeight = 480;
#define MY_HOUSE 1
#define M_PI     3.14159265358979323846

/////////////////////////////////////////////////////////////
// callback functions
/////////////////////////////////////////////////////////////

void house(float r, float g, float b, float x, float y, float z,
	float scale, float angle)
{
  glPushMatrix();
  glPolygonMode(GL_FRONT, GL_FILL);
  glTranslatef(x,y,z);
  glColor3f(r, g, b);
  glRotatef(angle, 0.0, 0.0, 1.0);
  glScalef(scale, scale, scale);
  glCallList(MY_HOUSE);
  glPopMatrix();
} 
  

void myDisplay(void)
{
  glClear(GL_COLOR_BUFFER_BIT);	// clear screen
	// Exercise: what would happen if you do not clear screen?
  glColor3f(0.0f, 0.0f, 1.0f);		// pen is blue

  // draw houses
  float del = 0.1;
  for (int i=0; i< 10; i++) {
    house(1.0 -i*del, 0, i*del,
	i*55, 10, 0,
	0.5, 10);
  }
  for (int i=0; i< 10; i++) {
    house(0, 1.0 -i*del, i*del,
	i*75, 100, 0,
	0.7, -20);
  }
  float up = 45*tan(15*M_PI/180);
  for (int i=0; i< 10; i++) {
    house(1.0 -i*del, i*del, 0,
	i*45, 200+i*up, 0,
	0.4, 15);
  }
  glFlush();
}//myDisplay()
  
/////////////////////////////////////////////////////////////
// MAIN PROGRAM
/////////////////////////////////////////////////////////////

void main(int argc, char** argv) 
{

  /////////////////////////////////////////////////////////////
  // initialization and create screen window
  /////////////////////////////////////////////////////////////

  glutInit(&argc, argv);  		// initialize toolkit
  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // display mode (single buffer)
  glutInitWindowSize(screenWidth, screenHeight); // window size
  glutInitWindowPosition(100, 150);	// position of top right corner
  glutCreateWindow("Pretty Rows of Houses");	// open it

  glClearColor(1.0, 1.0, 1.0, 0.0);	// background is white (default black)
  glColor3f(0.0f, 0.0f, 1.0f);		// pen is blue (default black)
  glPointSize(2.0);			// dot is 2pixels wide (default 1)
  glMatrixMode(GL_PROJECTION);		// set camera shape
  glLoadIdentity();			// initialize projection matrix
  gluOrtho2D(0.0, (GLdouble)screenWidth,
   	0.0, (GLdouble)screenHeight);	// set matrix for 2D graphics
  glMatrixMode(GL_MODELVIEW);		// go back to default
  /////////////////////////////////////////////////////////////
  // Modeling
  /////////////////////////////////////////////////////////////

  GLint w = 100; GLint h = 50;
  GLint rw = 20; GLint rh = 20;
  GLint dw = 8; GLint dh = 30;
  glNewList(MY_HOUSE, GL_COMPILE);
    glBegin(GL_POLYGON);
          glVertex2d (0, 0);
          glVertex2d (w, 0);
          glVertex2d (w, h);
          glVertex2d (w-rw, h+rh);
          glVertex2d (rw, h+rh);
          glVertex2d (0, h);
    glEnd();
    glColor3f(0, 0, 0);
    glBegin(GL_LINES);
	  // roofline:
	  glVertex2d (0,h);
	  glVertex2d (w,h);
	  // door:
	  glVertex2d ((w/2) - dw, 0);
	  glVertex2d ((w/2) - dw, dh);
	  glVertex2d ((w/2) - dw, dh);
	  glVertex2d ((w/2) + dw, dh);
	  glVertex2d ((w/2) + dw, dh);
	  glVertex2d ((w/2) + dw, 0);
    glEnd();
  glEndList();

  /////////////////////////////////////////////////////////////
  // register callback functions
  /////////////////////////////////////////////////////////////

  glutDisplayFunc(myDisplay);	   // redraw window event


  /////////////////////////////////////////////////////////////
  glutMainLoop();	// mandatory final call to glut
  /////////////////////////////////////////////////////////////
}//main

/////////////////////////////////////////////////////////////
// The end
/////////////////////////////////////////////////////////////