/************************************************************
 Add Opengl32.lib glu32.lib glut32.lib to
   Project->Setting->Link->General->Object/Library Modules.
*************************************************************/

// Source: http://www.site.uottawa.ca/~nbobic/csi4130


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


#define M_PI (4*atan(1))
/* animation step */
int step;


void circle( GLint res, GLfloat radius ){

	int i;

	glBegin(GL_POLYGON);
	for (i=0;i<res;i++)
		glVertex2f(radius * cos(2.0*M_PI*i/res),
		radius * sin(2.0*M_PI*i/res));
	glEnd();
}

void arc( GLint res, GLfloat radius , float startAngle, float endAngle){

	int i;

	glBegin(GL_POLYGON);
	glVertex2f(0.0,0.0);
	for (i=0;i<=res;i++)
		glVertex2f(radius * cos(startAngle+(endAngle-startAngle)*i/res), 		radius * sin(startAngle+(endAngle-startAngle)*i/res));
	glEnd();
}


void drawWheel(void){

	glColor3f(1.0,0.0,0.0);
	circle(20,10.0);
	glColor3f(0.0,1.0,0.0);

	glPushMatrix();
	glTranslatef(5.0,0.0,0.0);
	circle(20,3.0);
	glPopMatrix();

	glPushMatrix();
	glTranslatef(0.0,5.0,0.0);
	circle(20,3.0);
	glPopMatrix();

	glPushMatrix();
	glTranslatef(-5.0,0.0,0.0);
	circle(20,3.0);
	glPopMatrix();

	glPushMatrix();
	glTranslatef(0.0,-5.0,0.0);
	circle(20,3.0);
	glPopMatrix();

}


void drawBody(void){
	glColor3f(0.0,0.0,1.0);

	glRectf(15.0,0.0,45.0,15.0);

	glPushMatrix();
	glTranslatef(15.0,0.0,0.0);
	arc(10,15.0,M_PI/2.0,M_PI);
	glTranslatef(30.0,0.0,0.0);
	arc(10,15.0,0.0,M_PI/2.0);
	glTranslatef(-17.5,15.0,0.0);
	arc(10,15.0,0.0,M_PI);
	glColor3f(1.0,1.0,1.0);
	glTranslatef(0.0,2.0,0.0);
	arc(10,10.0,0.0,M_PI/2.0);
	glPopMatrix();
}

void displayWin(void){

	glClearColor(1.0,1.0,1.0,0.0);
	glClear(GL_COLOR_BUFFER_BIT);
	glShadeModel(GL_FLAT);

	glPushMatrix();
	glTranslatef(5.0+step,30.0,0.0);

	/* draw car body */
	drawBody();

	glPushMatrix();
	glTranslatef(15.0,0.0,0.0);
	glRotatef(-step*10.0,0.0,0.0,1.0);
	drawWheel();
	glPopMatrix();

	glPushMatrix();
	glTranslatef(45.0,0.0,0.0);
	glRotatef(-step*10.0,0.0,0.0,1.0);
	drawWheel();
	glPopMatrix();

	glPopMatrix();

	glFlush();
}

void reshapeWin( int w, int h ){

	float ar;

	/* correct the viewport */
	glViewport(0.0,0.0,w,h);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	ar = ((float) w)/h;
	if(ar > 1.0)
		glOrtho(0.0,100.0*ar,0.0,100.0,10.0,-10.0);
	else
		glOrtho(0.0,100.0,0.0,100.0/ar,10.0,-10.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}


void animate(int value){
	/* stop after 30 steps */
	if(value == 30)
	  {
	    // return;
	    value=0;
	    step=0;
	  }

	glutPostRedisplay();
	step++;
	/* call animate again in 200 mili-Secs */
	glutTimerFunc(200,animate,step);
}

void menuControl(int value){

	switch (value){
	case 1:
		/* call animate in 200 mili-Secs */
		glutTimerFunc(200,animate,step);
		break;
	case 2:
		step = 0;
		/* call animate in 200 mili-Secs */
		glutTimerFunc(200,animate,step);
		break;
	case 101:
		exit(1);
		break;
	}
}



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

	glutInit(&argc,argv);

	/* window definition and creation */
	/* the viewport is the same as window coords */
	glutInitWindowSize(800,800);
	glutInitWindowPosition(50,50);
	glutCreateWindow("Animation: Flickering");

	/* the reshape function */
	glutReshapeFunc(reshapeWin);

	/* the display function */
  	glutDisplayFunc(displayWin);

	glutCreateMenu(menuControl);
	glutAddMenuEntry("Start",1);
	glutAddMenuEntry("Restart",2);
	glutAddMenuEntry("Exit",101);
	glutAttachMenu(GLUT_RIGHT_BUTTON);

	glutMainLoop();

	return 0;
}