include glut include Windows include cstdio include iostream GLUnurbs

#include "glut.h"
#include <Windows.h>
#include <cstdio>
#include <iostream>

GLUnurbs* nrbsObject;

float ps[4] = {10, 20, 30, 0};

float dfvl[4] = {1, 1, 1, 1};
void init()
{
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_AUTO_NORMAL);
    glLightfv(GL_LIGHT0, GL_POSITION, ps);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, dfvl);
    glShadeModel(GL_SMOOTH);

    glColor3f(1, 1, 1);
    glClearColor(0, 0, 0, 0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    nrbsObject = gluNewNurbsRenderer();
    gluNurbsProperty(nrbsObject, GLU_SAMPLING_TOLERANCE, 25.0);
    glPointSize(10);

}



void generateKnot(int pointCount, int degree, float* knot, int& knotSize)
{
    int k = degree + 1;
    int n = pointCount - 1;
    for (int i = 1; i <= n + k + 1; ++i)
    {
        if (i <= k)
        {
            knot[i - 1] = 0;
        }
        else
            if(i <= n + 1)
            {
                knot[i - 1] = i - k;
            }
            else
            {
                knot[i - 1] = n - k + 2;
            }
    }
    knotSize = n + k + 1;
}

float knot1[30];
float knot2[30];

int pnt1 = 4;
int pnt2 = 4;

float ctlarray[4][4][4] = {0.10, 0.0, 0.0, 1.0,
    0.20, 0.0, 0.0, 1.0,
    0.30, 0.0, 0.0, 1.0,
    0.40, 0.0, 0.0, 1.0,

    0.10, 0.10, 0.0, 1.0,
    0.20, 0.1, 0.5, 1.0,
    0.30, 0.1, 0.0, 1.0,
    0.40, 0.1, 0.0, 1.0,

    0.10, 0.2, 0.0, 1.0,
    0.20, 0.2, 0.0, 1.0,
    0.30, 0.2, 0.0, 1.0,
    0.40, 0.2, 0.0, 1.0,

};


int step = 2;

void Display()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    int knot1size = 0;
    int knot2size = 0;



    generateKnot(pnt1, step, knot1, knot1size);
    generateKnot(pnt2, step, knot2, knot2size);
    
    
    for(int i = 0; i < pnt1; ++i)
        for (int j = 0; j < pnt2; ++j)
        {
            glBegin(GL_POINTS);
            glVertex4f(ctlarray[i][j][0], ctlarray[i][j][1], ctlarray[i][j][2], ctlarray[i][j][3]);
            glEnd();
        }
        
    gluBeginSurface(nrbsObject);
    gluNurbsSurface(nrbsObject, knot1size, (GLfloat*)knot1, knot2size, (GLfloat*)knot2, 4 * 4,  4, &ctlarray[0][0][0], step + 1, step + 1, GL_MAP2_VERTEX_4);
    gluEndSurface(nrbsObject);
        
        glRotatef(0.1, 1.0, 1.0, 1.0);
        glutPostRedisplay();
    glutSwapBuffers();
}

void main()
{
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(480, 480);
    glutInitWindowPosition(100, 100);
    
    glutCreateWindow(" dfa");
    init();
    glutDisplayFunc(Display);
    glutMainLoop();

}