2ndLab

#include<windows.h>
#include<GL/glut.h>

void myInit(void)
{
	glClearColor(1.0, 1.0, 1.0, 0.0); //background color is white
	glColor3f(0.0f, 0.0f, 0.0f); //drawing color is black
	glPointSize(4.0); //a dot is 2 by 2 pixels

	//initialize view
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-1.0,1.0,-1.0,1.0,-1.0,1.0);
	gluOrtho2D(0.0,1024.0,0.0,768.0);
}
void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT); //clear the screen
	//draw a rectangle with background

	//Line drawing algorithm
	glPointSize(2.0);

	GLint x,y, x1=50, x2=100, y1=100, y2=200;
	GLint dx, dy, inc1, inc2, d;

	x = x1;
	y = y1;

	dx = x2-x1;
	dy = y2-y1;

	inc1 = 2 * dy;
	inc2 = 2 * (dy-dx);

	d = inc1 - dx;
	while(x <= x2)
	{
		glBegin(GL_POINTS);
		{
			glVertex2i(x, y);
		}
		glEnd();
		x++;
		if(d<0)
			d=d+inc2;
		else
		{
			d = d + inc2;
			y++;
		}
	}
	glFlush(); //send all output to display
}
int main (int argc, char** argv)
{
	glutInit(&argc, argv); //initialize the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //set the display
	glutInitWindowSize(1024,768);
	//set window position on screen
	glutInitWindowPosition(100,150);
	//open the screen window and set the name
	glutCreateWindow("My First Window");

	glutDisplayFunc(myDisplay);
	myInit();
	glutMainLoop(); //go into a perpetual loop

	//fprinitf(stderr, "Hello!\n");
	return 1;
}