// Computer Graphics - Amir Hesami
// big_point.cpp


#include <GL/glut.h>

/**********************************************************
 * Use the following stements under windows only
 **********************************************************/

#pragma comment(lib, "opengl32.lib")  // Link OpenGL32.lib
#pragma comment(lib, "glu32.lib")	  // Link Glu32.lib
#pragma comment(lib, "glut32.lib")    // Link Glut32.lib
#pragma comment(linker, "/entry:\"mainCRTStartup\"" )  // set the entry point to be main()
#pragma comment(linker, "/subsystem:\"Windows\"" )  // set the entry point to be main()

void display();

void init( );

int main(int argc, char** argv)
{
	//Initialize glut and specifies command line options
	glutInit(&argc, argv);

	//Initializes opreation's mode and coloring system
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    
	//Specifying the window's size
	glutInitWindowSize(500,500);
    
	//Specifying the window's position
	glutInitWindowPosition(100,100);
    
	//Create the window
	glutCreateWindow("Big Points");
    
	//Calling the drawing function
	glutDisplayFunc(display);
 
	init();

    //Runing the program
	glutMainLoop();
	return 0;
}

void display()
{
	//Clear the window
	glClear(GL_COLOR_BUFFER_BIT);

	//Set the drawing color to red
	glColor3f(1.0,0.0,0.0);
    glPointSize(4.0);
	//draw unit square polygon
	glBegin(GL_POINTS);
	   glVertex2f(-0.5,-0.5);
	   glVertex2f(-0.5,0.5);
	   glVertex2f(0.5,0.5);
	   glVertex2f(0.5,-0.5);
    glEnd();

	//Flush the buffer
	glFlush();
}

void init()
{
	//Set the background color
	glClearColor(1.0,1.0,1.0,1.0);
    
	//Sets the mode of matrix operation
	glMatrixMode(GL_PROJECTION);
    
	//Initalizes the transformation matrix to Identity matrix
	glLoadIdentity();
    
	//Viewing the image in the screen
	gluOrtho2D(-1.0,1.0,-1.0,1.0);
}