t4.cpp

#include<GL/glut.h>
#include<math.h>
#include<stdio.h>
int bzco[4][2]={{0,0},{49,201},{201,99},{320,300}},c[4],n=3;
int s1x,s1y,s2x,s2y;
void bezierCoefficients(int n,int *c)
{
	int k,i;
	for(k=0;k<=n;k++)
	{
		c[k]=1;
        //int ga,gb=0,gx=1;
		for(i=n;i>=k+1;i--)
		    c[k]*=i;
            //c[k] = 1 / (1+ exp (i));
		
		//c[k]=1;

		for(i=n-k;i>=2;i--)
			c[k]/=i;
                        //c[k] = 1 / (1+ exp (i));




            /*x <- c(-10:10)
            b = 0 # intercept
            m = 1 # slope
            y <- exp((b + m*x)) / (1 + exp((b + m*x))
            */

           /*
           c[k] = exp((gb + i*gx)) / (1 + exp((gb + i*gx)));
           */
	}
}

void display(void)
{
int k;

float x,y,u,blend;

	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(0.0,0.0,1.0);
	glLineWidth(3.0);
	glBegin(GL_LINE_STRIP);

	for(u=0;u<1.0;u+=0.001)
	{x=0;y=0;
		for(k=0;k<4;k++)
		{
			blend=c[k]*pow(u,k)*pow(1-u,n-k);
			x+=bzco[k][0]*blend;
			y+=bzco[k][1]*blend;
		}
		glVertex2f(x,y);

	}
	glEnd();

	//moving points
	
	// glBegin(GL_POINTS);
	// glVertex2f(bzco[1][0],bzco[1][1]);
	// glVertex2f(bzco[2][0],bzco[2][1]);
	// glEnd();
	

	glFlush();
	glutSwapBuffers();
}
void myinit()
{
	glClearColor(1.0,1.0,1.0,1.0);
		glColor3f(1.0,0.0,0.0);
		glPointSize(5.0);
		gluOrtho2D(0.0,320.0,0.0,300.0);
}
void motion(void)
{
	bzco[1][0]+=s1x;
	bzco[1][1]+=s1y;
	bzco[2][0]+=s2x;
	bzco[2][1]+=s2y;
if(bzco[1][0]<0||bzco[1][0]>320)
{
	s1x=-s1x;
}
if(bzco[1][1]<0||bzco[1][1]>300)
{
	s1y=-s1y;
}
if(bzco[2][0]<0||bzco[2][0]>320)
{
	s2x=-s2x;
}
if(bzco[2][1]<0||bzco[2][1]>300)
{
	s2y=-s2y;
}
glutPostRedisplay();
}
int main(int argc, char ** argv)
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);
	glutInitWindowSize(320,300);

	glutCreateWindow("Logistic Function");
	glutDisplayFunc(display);
	glutIdleFunc(motion);
	myinit();
	bezierCoefficients(n,c);
	s1x=-1;s1y=-1;s2x=-1;s2y=1;
	glutMainLoop();
	return 0;

}