C++二次和三次B样条曲线

#include <gl/glut.h>
#include <gl/gl.h>
#include <stdio.h>
GLfloat x_coord[100], y_coord[100];

int nPoints = 0;

int j=0;

inline GLfloat x_convert (int x)
{
return -5.0+x/249.0*10;
}

inline GLfloat y_convert (int y)
{
return 5.0 - y/249.0*10;
}

void init(){  
  glClearColor(1,1,1,0);

}
void myReshape(int w,int h)
{
glViewport(0,0,(GLsizei)w,(GLsizei)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//gluPerspective(45.0,(GLfloat)w/(GLfloat)h,1.0,50.0);
if(w<=h)