pointsWithInput.c

#include <GL/freeglut.h>
#include <GL/gl.h>
#include <stdio.h>
struct Point
{
GLfloat x,y;
};
struct Point p[100000];
int count = 0;
void readInput()
{
FILE *fptr = fopen("input.txt", "r");
if(fptr)
{
while(fscanf(fptr, "%f %f", &(p[count].x), &(p[count].y))!=EOF)
{

printf("%f %f", p[count].x, p[count].y);
count++;
}
fclose(fptr);
}
}
void renderFunction()
{
int i=0;
glClearColor(1.0, 1.0, 1.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0.0, 0.0, 1.0);
glPointSize(5) ;
glBegin(GL_LINE_LOOP) ;
while(i < count)
{
glVertex2f(p[i].x, p[i].y);
i++;
}
glEnd();
glFlush();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE);
glutInitWindowSize(500,500);
glutInitWindowPosition(100,100);
readInput();
glutCreateWindow("OpenGL - First window demo");
glutDisplayFunc(renderFunction);
glutMainLoop();
return 0;
}