//Jeff Chastine
#include <Windows.h>
#include <GL\glew.h>
#include <GL\freeglut.h>
#include <iostream>

using namespace std;

void changeViewPort(int w, int h)
{
	glViewport(0, 0, w, h);
}

void render()
{
	glClearColor(1.0, 0.0, 0.0, 1.0);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	//	glLineWidth(4.0);

	GLfloat x = -1.0, y;
	int draw = 0;

	glBegin(GL_LINES);
	glColor3f(1.0, 1.0, 1.0);
	// Tr?c hoành
	glVertex2f(-1.0, 0);
	glVertex2d(1.0, 0);
	// Tr?c tung
	glVertex2d(0, -1.0);
	glVertex2d(0, 1.0);
	glEnd();

	glBegin(GL_LINES);
	glColor3f(1.0, 1.0, 1.0);
	while (x < 1.0)
	{
		y = 0.5 * sin(x * 4);
		draw++;
		if (draw % 3 == 0)
		{
			glVertex2f(x, y);
			glVertex2f(x, 0);
		}
		x += 0.01;
	}
	glEnd();

	x = -1.0;
	glBegin(GL_LINE_STRIP);
	glColor3f(0.0, 0.0, 1.0);
	while (x < 1.0)
	{
		y = 0.5 * sin(x * 4);
		glVertex2f(x, y);
		x += 0.01;
	}

	glEnd();

	glutSwapBuffers();
}



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

	// Initialize GLUT
	glutInit(&argc, argv);
	// Set up some memory buffers for our display
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
	// Set the window size
	glutInitWindowSize(600, 600);
	// Create the window with the title "Hello,GL"
	glutCreateWindow("Beginning OpenGL");
	// Bind the two functions (above) to respond when necessary
	glutReshapeFunc(changeViewPort);
	glutDisplayFunc(render);

	// Very important!  This initializes the entry points in the OpenGL driver so we can 
	// call all the functions in the API.
	GLenum err = glewInit();
	if (GLEW_OK != err) {
		fprintf(stderr, "GLEW error");
		return 1;
	}


	glutMainLoop();
	return 0;
}