// An rudimentary example program as a starting point for your 1st assignment
// Simply draw some interesting figure of your own design and email me the
// source code ---- NO BINARIES PLEASE!

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <GL/glut.h> // In OS X change to #include <GLUT/glut.h>

#define WINDOW_HEIGHT 500
#define WINDOW_WIDTH 500

// Parameters
float WinX = 0, WinY = 0;

static void Draw(void) {	// How often is this called on your machine?
	glClear(GL_COLOR_BUFFER_BIT);	// What happens if we don't do this?

	// Draw some innovative figure here after the clear but before flush.
        glBegin(GL_LINES);
        glVertex2f(0, 0);
        glVertex2f(WinX, WinY);
        glEnd();

	glFlush();
	glutReportErrors();
	glutPostRedisplay();
}

static void Reshape(int width, int height) {	// Called when window resized
	int viewport_width = WinX = width;
	int viewport_height = WinY = height;
	glViewport(0, 0, viewport_width, viewport_height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0, viewport_width, 0, viewport_height, 1, 10);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0, 0, 7, 0, 0, 0, 0, 1, 0);
	glClear(GL_COLOR_BUFFER_BIT);
}

void Initialize(int argc, char **argv) {
	glutInit(&argc, argv);

	// Initialize GLUT Window.
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowSize(WINDOW_WIDTH, WINDOW_HEIGHT);
	glutCreateWindow("Example Line");

	// Assign Callback functions for reshape event and display events.
	glutReshapeFunc(Reshape);
	glutDisplayFunc(Draw);

	// Initialize OpenGL parameters to desired states.
	glClearColor(0.0, 0.0, 1.0, 1);
	glDisable(GL_DEPTH_TEST);
	glDisable(GL_LIGHTING);
	glEnable(GL_COLOR_MATERIAL);

}

int main(int argc, char **argv) {
	Initialize(argc, argv);
	glutReportErrors();	// Tell Glut to report any errors that occured.
	glutMainLoop();		// Begin main program loop
	return(0);		// This will not be reached
}