12. bezier curve.txt

#include <Windows.h>
#include <GL\glew.h>
#include <GL\freeglut.h>
#include <iostream>
#include<stdio.h>
int x1, x2, x3, y11, y2, y3;

void myInit() 
{
	glClear(GL_COLOR_BUFFER_BIT);
	glClearColor(1.0, 0.0, 0.0, 0.0);
	glMatrixMode(GL_PROJECTION);
	gluOrtho2D(0, 500, 0, 500);
}

void draw_pixel(int x, int y)
{
	glBegin(GL_POINTS);
	glColor3f (1.0, 1.0, 1.0);
	glVertex2i(x, y);
	glEnd();
}
void draw_gray(int x, int y)
{
	glBegin(GL_POINTS);
	glColor3f (0.5, 0.5, 0.5);
	glVertex2i(x, y);
	glEnd();
}
void draw_curve()
{
	double u,x,y;
	draw_pixel(x1,y11);
	draw_pixel(x3,y3);
	for (u=0.01;u<1;u=u+0.01)
	{
		x=(1-u)*(1-u)*x1+2*(1-u)*u*x2+u*u*x3;
		y=(1-u)*(1-u)*y11+2*(1-u)*u*y2+u*u*y3;
		draw_pixel(x,y);
	}

}


void myDisplay() 
{
	//draw_line(0,500,250,250);
	//draw_line(250,250,0,500);
	draw_curve();
	glFlush();
}

void main(int argc, char **argv)
{

	printf( "Enter (x1, y1, x2, y2, x3, y3)\n");
	scanf(" %d %d %d %d %d %d", &x1, &y11, &x2, &y2, &x3, &y3);
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
	glutInitWindowSize(500, 500);
	glutInitWindowPosition(0, 0);
	glutCreateWindow("Bezier Curve Drawing");
	myInit();
	glutDisplayFunc(myDisplay);
	glutMainLoop();
}