/* NURB curve (2-dimension)

Written by Caroline Geiersbach and Scott D. Anderson
scott.anderson@acm.org
Summer 2003
*/

#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include "tw.h"
#include <math.h>

twTriple points[4][4];
GLUnurbsObj *myNurb;

void initSurface() {
  int u, v;
  for (u = 0; u < 4; u++) {
    for (v = 0; v < 4; v++) {
      points[u][v][0] = 2.0*((GLfloat)u-1.5);
      points[u][v][1] = 2.0*((GLfloat)v-1.5);

      if((u==1 || u==2) && (v==1 || v==2))
        points[u][v][2] = 3.0;
      else
        points[u][v][2] = -3.0;
    }
  }
}

void myInit() {
  twTriple myColor = {0.1,0.6,0.1};
  twColor(myColor,0.2,128);

  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_NORMALIZE);
  
  initSurface();

  myNurb = gluNewNurbsRenderer();
  gluNurbsProperty(myNurb, GLU_SAMPLING_TOLERANCE, 25.0);
  gluNurbsProperty(myNurb, GLU_DISPLAY_MODE, GLU_FILL);
}

void display(void) {
    glClearColor(1,1,1,1);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    twCamera();

    GLfloat knots[8] = {0.0,0.0,0.0,0.0,1.0,1.0,1.0,1.0};

    glPushMatrix();
    glRotatef(40,1,0,0);
    gluBeginSurface(myNurb);
    gluNurbsSurface(myNurb, 8, knots, 8, knots, 4*3, 3,
                    &points[0][0][0], 4, 4, GL_MAP2_VERTEX_3);
    gluEndSurface(myNurb);
    glPopMatrix();
    glFlush();
    glutSwapBuffers(); 
}

int main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    twInitWindowSize(650, 650);
    twBoundingBox(-5,5,-5,5,-5,5);
    glutCreateWindow("NURBS!");
    glutDisplayFunc(display);
    twMainInit();
    myInit();
    glutMainLoop();
    return 0;
}