#include <stdlib.h>
#include "glut.h"
#include <iostream>
#include <math.h>

using namespace std;
void init(void);
void display(void);
void keyboardread(void);
void drawHouse(void);
int theta;

void init(void)
{
	glClearColor(0.0, 0.0, 0.0, 0.0);
	glShadeModel(GL_FLAT);   //uses GL_SMOOTH or GL_FLAT
}

void drawHouse(void)
{
	//Description:
	//This routine draws the house from OGL primitives
	//Note all polygon windings are counter clockwise
	//If you look at the front of a polygon its vertices are
	//listed so that the polygon is drawn in counterclockwise manner.
	//glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
	//  glPolygonMode(GL_BACK,GL_FILL); //uses also GL_FRONT_AND_BACK; GL_FILL, GL_POINT, GL_LINE  
	//  glPolygonMode(GL_FRONT,GL_FILL);// to spec. whether poly's. front and back are drawn filled
	// as lines or points

	//  glCullFace(GL_BACK);//discards front or back facing polygons
	//  glEnable(GL_CULL_FACE);  

	glBegin(GL_QUADS);

	glVertex3f(0.0, 0.0, 0.0);//front 
	glVertex3f(0.0, -2.0, 0.0);
	glVertex3f(1.0, -2.0, 0.0);
	glVertex3f(1.0, 0.0, 0.0);

	glVertex3f(1.0, 0.0, 0.0);//right 
	glVertex3f(1.0, -2.0, 0.0);
	glVertex3f(1.0, -2.0, -1.0);
	glVertex3f(1.0, 0.0, -1.0);

	glVertex3f(0.0, 0.0, 0.0);//left 
	glVertex3f(0.0, 0.0, -1.0);
	glVertex3f(0.0, -2.0, -1.0);
	glVertex3f(0.0, -2.0, 0.0);

	glVertex3f(0.0, -2.0, 0.0); //bottom
	glVertex3f(0.0, -2.0, -1.0);
	glVertex3f(1.0, -2.0, -1.0);
	glVertex3f(1.0, -2.0, 0.0);

	glVertex3f(0.0, 0.0, -1.0);//back 
	glVertex3f(1.0, 0.0, -1.0);
	glVertex3f(1.0, -2.0, -1.0);
	glVertex3f(0.0, -2.0, -1.0);
	glEnd();

	glBegin(GL_TRIANGLES);
	glVertex3f(0.0, 0.0, 0.0);//front gable 
	glVertex3f(1.0, 0.0, 0.0);
	glVertex3f(0.5, 1.25, 0.0);

	glVertex3f(0.0, 0.0, -1.0);//back gable 
	glVertex3f(0.5, 1.25, -1.0);
	glVertex3f(1.0, 0.0, -1.0);
	glEnd();

	glBegin(GL_QUADS);
	glVertex3f(0.0, 0.0, 0.0);//left roof 
	glVertex3f(0.5, 1.25, 0.0);
	glVertex3f(0.5, 1.25, -1.0);
	glVertex3f(0.0, 0.0, -1.0);

	glVertex3f(0.5, 1.25, 0.0);//right roof 
	glVertex3f(1.0, 0.0, 0.0);
	glVertex3f(1.0, 0.0, -1.0);
	glVertex3f(0.5, 1.25, -1.0);
	glEnd();
}

void keyboardread(unsigned char key, int x, int y)
{
	switch (key) {
	case 'r':
		theta = (theta + 10) % 360;
		glutPostRedisplay();
		cout << theta << endl;
		break;
	case 'l':
		theta = (theta - 10) % 360;
		glutPostRedisplay();
		break;
	}
}

void display(void)
{
	//select clearing background colour
	//if you don't do this then OGL will display
	//whatever was last drawn in the buffer
	//make it black
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(0.0, 1.0, 1.0);
	glLoadIdentity();//reset transformation (of modelview matrix)
	gluLookAt(5.0*sin(float(theta)*0.0175), 5.0, 5.0*cos(float(theta)*0.0175), 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
	//  place camera - it rotates about the origin, on y = 5.0 plane,
	// with a radius of 5.0; 0,0,0 - aim lens towards 0,0,0; 
	//  0,1,0 - the up vector defines an unique orientation.

	//  gluLookAt(5.0, 5.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);  
	//  5,5,5 - place camera ; 0,0,0 - aim lens towards 0,0,0; 
	//  0,1,0 - the up vector defines an unique orientation

	drawHouse();

	glTranslatef(1.0, 0.0, 0.0);
	glColor3f(0.0, 1.0, 0.0);

	drawHouse();

	glTranslatef(2.0, 0.0, -1.0);
	glRotatef(90.0, 0.0, 1.0, 0.0);
	glColor3f(0.0, 0.0, 1.0);

	drawHouse();

	//glutWireCube(1.0);
	glFlush();
}

void reshape(int w, int h)
{
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);
	//             l,r,bot,top,near,far
	glMatrixMode(GL_MODELVIEW);
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(250, 250);
	glutInitWindowPosition(100, 100);
	glutCreateWindow("3D house");
	init();
	glutReshapeFunc(reshape);
	glutDisplayFunc(display);
	glutKeyboardFunc(keyboardread);
	glutMainLoop();
	return 0;
}