#include <iostream>
#include <stdlib.h>
#include<math.h>
#ifdef __APPLE__
#include <OpenGL/OpenGL.h>
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

using namespace std;

//Called when a key is pressed
void handleKeypress(unsigned char key, int x, int y) {
	switch (key) {
		case 27: //Escape key
			exit(0);
	}
}

//Initializes 3D rendering
void initRendering() {
	glEnable(GL_DEPTH_TEST);
}

//Called when the window is resized
void handleResize(int w, int h) {
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0, (double)w / (double)h, 1.0, 200.0);
}

float _angle1 = 40.0f;
//float _angle2 = 30.0f;
//float _angle3 = 30.0f;
float _cameraAngle = 0.0f;
float x=0.0f;
float y=-1.0f;
float z=0.0f;
//Draws the 3D scene
void drawScene() {
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glMatrixMode(GL_MODELVIEW); //Switch to the drawing perspective
	glLoadIdentity(); //Reset the drawing perspective
	glRotatef(-_cameraAngle, 0.0f, 1.0f, 0.0f); //Rotate the camera
	glTranslatef(0.0f, 1.0f, -5.0f); //Move forward 5 units

	glPushMatrix(); //Save the transformations performed thus far




	glBegin(GL_LINES);

    glVertex3f(0.0f, 0.0f, 0.0f);
	glVertex3f(1.0, 0.0f, 0.0f);

	 glVertex3f(0.0f, 0.0f, 0.0f);
	  glVertex3f(0.0f, -1.0f, 0.0f);

    glVertex3f(0.0, -1.0f, 0.0f);
    glVertex3f(1.0, -1.0f, 0.0f);

     glVertex3f(1.0f, 0.0f, 0.0f);
      glVertex3f(1.0f, -1.0f, 0.0f);




	glEnd();

    glBegin(GL_QUADS);
     glVertex3f(x-0.2f, y-0.2f, z);
   glVertex3f(x-0.2f, y+0.2f, z);
   glVertex3f(x+0.2f, y+0.2f, z);
    glVertex3f(x+0.2f, y-0.2f, z);




	glEnd();

	glPopMatrix(); //Undo the move to the center of the triangle

	glutSwapBuffers();
}

void update(int value) {

	    x+=.01;

	if(x>1.0f && y<0.0f)
    {
        x=1.0f;
      y+=0.01;

    if(x==1.0f  && y>0.0f)
        {
            x-=0.1;
            y=0.0f;
          //  x=0.01;



    if(x<0.0f && y==0.0f)
    {
        x=0.0f;
        y-=0.01;
    }
        }}

	glutPostRedisplay(); //Tell GLUT that the display has changed

	//Tell GLUT to call update again in 25 milliseconds
	glutTimerFunc(25, update, 0);
}

int main(int argc, char** argv) {
	//Initialize GLUT
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(800, 800);

	//Create the window
	glutCreateWindow("Transformations and Timers ");
	initRendering();

	//Set handler functions
	glutDisplayFunc(drawScene);
	glutKeyboardFunc(handleKeypress);
	glutReshapeFunc(handleResize);

	glutTimerFunc(25, update, 0); //Add a timer

	glutMainLoop();
	return 0;
}