// program to bounce around a 2d mass spring system with (optional) gravity and floor
// Date: 10/17/08
// Author: CSCI 323 class

#include <iostream>
#include <cmath>
#include "glut.h"
#include "point.h"
#include <ctime>

using namespace std;


int NPTS = 10;		// number of points on each side
point *jello;
clock_t lastTime;
clock_t curTime;
double elapsed;

void init(void)
{
	int i, j, index;
	double x, y;

// jello initialization

	jello = new point[NPTS*NPTS];

	for (i = 0; i < NPTS; i++)
		for (j = 0; j < NPTS; j++)
		{
			index = i*NPTS+j;
			x = /*-0.15*/ + (j-NPTS/2)*jello[index].SRL*0.707 - (i-NPTS/2)*jello[index].SRL*0.707;
			y = 0.6 + (i-NPTS/2)*jello[index].SRL*0.707 + (j-NPTS/2)*jello[index].SRL*0.707;
			jello[index].setx(x);
			jello[index].sety(y);
			jello[index].setnewx(x);
			jello[index].setnewy(y);

		}

// graphics initialization
	glClearColor(0.0, 0.0, 0.0, 1.0);

	lastTime = clock();


	return;
}



void display(void)
{
	int i, j, index;

	glClear(GL_COLOR_BUFFER_BIT);

	for (i=0; i<NPTS-1; i++)
		for (j=0; j<NPTS-1; j++)
		{
			index = i*NPTS+j;
			glColor3f(0.1, 0.9, 0.3);
			glBegin(GL_LINE_LOOP);
				glVertex3d(jello[index].getx(), jello[index].gety(), 0.0);
				glVertex3d(jello[index+1].getx(), jello[index+1].gety(), 0.0);
				glVertex3d(jello[index+NPTS+1].getx(), jello[index+NPTS+1].gety(), 0.0);
				glVertex3d(jello[index+NPTS].getx(), jello[index+NPTS].gety(), 0.0);
			glEnd();
		}

	glutSwapBuffers();
	return;
}

void animate(void)
{
	clock_t curTime;
	int i, j,index;

	curTime = clock();
	elapsed = (double)(curTime - lastTime)/CLOCKS_PER_SEC;
	lastTime =  curTime;
//	elapsed = 0.00001;
	if (elapsed > 0.0)
	{
		lastTime = curTime;
		for (i=0; i<NPTS; i++)
			for (j=0; j<NPTS; j++)
			{
				index = i*NPTS+j;
				jello[index].calcForces();
				jello[index].calcNewPos();
			}
		for (i=0; i<NPTS*NPTS; i++)
		{
			jello[i].setx(jello[i].getnewx());
			jello[i].sety(jello[i].getnewy());
		}
		glutPostRedisplay();
	}
}



int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(500, 500);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	init();
	glutDisplayFunc(display);
	glutIdleFunc(animate);
	glutMainLoop();
	return 0;
}