/*
 * ok, it's a very bad piece of code, but I wrote it hastily and 
 * was trying to just accomplish the effect, without thinking of
 * possible optimizations and cleanlyness
 * 
 * todo: 
	1. do everything with 1 NURB (at most 2)
	2. clean up the idle function -- remove hardcoded values of lr
	3. clean up the idle() so that init_surface is not called all
		that often.
	4. rewrite cleanly
 */

#include <GL/glut.h>
#include <math.h>

#define NURP 3
#define LAYERS 1

void init_surface(int lr); /* silly forward declaration */

GLfloat ctl[LAYERS][NURP][NURP][3];
int showPoints = 0;
int rewind = 0;
int fill = 0;
int rot = 0;

int spin_x, spin_y, spin_z; /* x-y rotation and zoom */
int h, w;                    /* height, width  of window */
int old_x, old_y, move_z;

GLUnurbsObj *theNurb[LAYERS];
static GLuint texname;


void move_down(int lr) {
	ctl[lr][0][0][2] =  0;
	ctl[lr][2][0][2] =  0;
	ctl[lr][0][2][2] =  0;
	ctl[lr][2][2][2] =  0;
}

void init_all() {
	int lr = 0;

	for(lr = 0;lr < LAYERS; lr++)
	 init_surface(lr);
	move_down(1);
}
/*
 *  Initializes the control points of the surface to a small hill.
 *  The control points range from -3 to +3 in x, y, and z
 */
void init_surface(int lr)
{

		ctl[lr][0][0][0] = -1;
		ctl[lr][0][0][1] = -1;
		ctl[lr][0][0][2] =  6;

		ctl[lr][0][1][0] = -3;
		ctl[lr][0][1][1] = -1;
		ctl[lr][0][1][2] =  2;

		ctl[lr][0][2][0] = -1;
		ctl[lr][0][2][1] = -1;
		ctl[lr][0][2][2] =  6;

		ctl[lr][1][0][0] = -1;
		ctl[lr][1][0][1] = -3;
		ctl[lr][1][0][2] =  2;

		ctl[lr][1][1][0] = -1;
		ctl[lr][1][1][1] = -1;
		ctl[lr][1][1][2] =  2;

		ctl[lr][1][2][0] = -1;
		ctl[lr][1][2][1] =  1;
		ctl[lr][1][2][2] =  2;

		ctl[lr][2][0][0] = -1;
		ctl[lr][2][0][1] = -1;
		ctl[lr][2][0][2] =  6;

		ctl[lr][2][1][0] =  1;
		ctl[lr][2][1][1] = -1;
		ctl[lr][2][1][2] =  2;

		ctl[lr][2][2][0] = -1;
		ctl[lr][2][2][1] = -1;
		ctl[lr][2][2][2] =  6;

}



/*  Initialize material property and depth buffer.
 */
void myinit(void)
{
	int lr;
	float dfuse[] = {1.0, 1.0, 1.0, 1.0};

    GLfloat mat_diffuse[] = { 0.7f, 0.7f, 0.7f, 1.0f };
    GLfloat mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
    GLfloat mat_shininess[] = { 100.0f };

    glClearColor (0.0, 0.0, 0.0, 1.0);
    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_diffuse);
    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess);

	glLightfv(GL_LIGHT0, GL_DIFFUSE, dfuse);
    glLightfv(GL_LIGHT1, GL_DIFFUSE, dfuse);
	glLightfv(GL_LIGHT2, GL_DIFFUSE, dfuse);

    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
	glEnable(GL_LIGHT1);
	glEnable(GL_LIGHT2);

    glDepthFunc(GL_LESS);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_AUTO_NORMAL);
    glEnable(GL_NORMALIZE);
	glPointSize(4);

    init_all();

	for(lr = 0; lr < LAYERS; lr++) {
		theNurb[lr] = gluNewNurbsRenderer();
		gluNurbsProperty(theNurb[lr], GLU_SAMPLING_TOLERANCE, 50.0);
		gluNurbsProperty(theNurb[lr], GLU_DISPLAY_MODE, GLU_FILL);
	}

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef (0.0, 0.0, -5.0);
}


float pos[3] = {1, 1, -2};
float pos2[3] = {0, 0, 1};
float pos3[3] = {1, 0, -1};


GLfloat knots[NURP*2] = {0.0, 0.0, 0.0, 1.0, 1.0, 1.0};
void display(void)
{
    int i, j;
	int lr;

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glLightfv(GL_LIGHT0, GL_POSITION, pos);
    glLightfv(GL_LIGHT1, GL_POSITION, pos2);
	glLightfv(GL_LIGHT2, GL_POSITION, pos2);

    glPushMatrix();
    glTranslatef(0, -2, spin_z - 10);
    glRotatef(spin_x+30, 0, 1, 0);
    glRotatef(spin_y-30, 1, 0, 0);
	glRotatef(rot, 0, 0, 1);
	for(lr = 0; lr < LAYERS; lr++) {
		gluBeginSurface(theNurb[lr]);
		gluNurbsSurface(theNurb[lr],
			NURP*2, knots,
			NURP*2, knots,
			NURP * 3,
			3,
			&ctl[lr][0][0][0],
			NURP, NURP,
			GL_MAP2_VERTEX_3);
		gluNurbsSurface(theNurb[lr],
			NURP*2, knots,
			NURP*2, knots,
			NURP * 3,
			3,
			&ctl[lr][0][0][0],
			NURP, NURP,
			GL_MAP2_TEXTURE_COORD_4);
		gluEndSurface(theNurb[lr]);
	}

	if(showPoints) {
		glDisable(GL_LIGHTING);
		glColor3f(0, 1, 1);

		glBegin(GL_POINTS);
		for(lr = 0; lr < LAYERS; lr++)
			for (i = 0; i < NURP; i++) 
				for (j = 0; j < NURP; j++) 
		   			glVertex3fv(ctl[lr][i][j]);
		glEnd();

		glEnable(GL_LIGHTING);
	}


    glPopMatrix();
    glutSwapBuffers();
}

void reshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective (45.0, (GLdouble)w/(GLdouble)h, 3.0, 80.0);

    glMatrixMode(GL_MODELVIEW);
}

void
menu(int value)
{
	int lr;
    switch (value) {
    case 0:
		for(lr = 0; lr < LAYERS; lr++)
			gluNurbsProperty(theNurb[lr], GLU_DISPLAY_MODE, (fill ? GLU_FILL : GLU_OUTLINE_POLYGON));
		fill = !fill;
	break;
//	case 1:
//		showPoints = !showPoints;
//		break;
	}

	glutPostRedisplay();
}

int down = 0, lastx;

int flagmov[4] = {0, 0, 0, 0};
float zeta = 0.9f;

void
mouse(int button, int state, int x, int y)
{

    switch(button) {
        case 0:
            old_x = x - spin_x;
            old_y = y - spin_y;
            break;
        case 2:
            old_y = y - spin_z;
            move_z = (move_z ? 0 : 1);
    }
            

    glutPostRedisplay();

}

void 
motion(x, y) {

    if(!move_z) {
        spin_x = x - old_x;
        spin_y = y - old_y;
    } else {
        spin_z = y - old_y;
    }

    glutPostRedisplay();
}


int num = 1;
int lr = 0, ld = 0;		
int movup = 0;

void idle(void) {

	if(movup && ctl[lr][0][0][2] < 6) {
				ctl[lr][0][0][2] += 0.04f;
				ctl[lr][2][0][2] += 0.04f;
				ctl[lr][0][2][2] += 0.04f;
				ctl[lr][2][2][2] += 0.04f;
				ctl[lr][1][1][2] -= 0.04f;

		} else if(ctl[lr][0][0][2] > 2 && !ld) {
			if(movup) 
				movup = 0;
			
					ctl[lr][0][0][2] -=0.04f;
					ctl[lr][0][0][0] -= 0.02f;
					ctl[lr][0][0][1] -= 0.02f;

					ctl[lr][2][0][2] -=0.04f;
					ctl[lr][2][0][0] += 0.02f;
					ctl[lr][2][0][1] -= 0.02f;

					ctl[lr][0][2][2] -=0.04f;
					ctl[lr][0][2][0] -= 0.02f;
					ctl[lr][0][2][1] += 0.02f;

					ctl[lr][2][2][2] -=0.04f;
					ctl[lr][2][2][0] += 0.02f;
					ctl[lr][2][2][1] += 0.02f;

					ctl[lr][1][1][2] += 0.04f;
		} else if(ctl[lr][0][0][2] > 2 && ld) {
			if(movup) 
				movup = 0;
			
					ctl[lr][0][0][2] -=0.04f;
					ctl[lr][0][0][0] += 0.02f;
					ctl[lr][0][0][1] += 0.02f;

					ctl[lr][2][0][2] -=0.04f;
					ctl[lr][2][0][0] -= 0.02f;
					ctl[lr][2][0][1] += 0.02f;

					ctl[lr][0][2][2] -=0.04f;
					ctl[lr][0][2][0] += 0.02f;
					ctl[lr][0][2][1] -= 0.02f;

					ctl[lr][2][2][2] -=0.04f;
					ctl[lr][2][2][0] -= 0.02f;
					ctl[lr][2][2][1] -= 0.02f;

					ctl[lr][1][1][2] += 0.04f;

		} else if(ctl[lr][0][0][2] > -2 && !ld) { 

					ctl[lr][0][0][2] -=0.04f;
					ctl[lr][0][0][0] += 0.02f;
					ctl[lr][0][0][1] += 0.02f;

					ctl[lr][2][0][2] -=0.04f;
					ctl[lr][2][0][0] -= 0.02f;
					ctl[lr][2][0][1] += 0.02f;

					ctl[lr][0][2][2] -= 0.04f;
					ctl[lr][0][2][0] += 0.02f;
					ctl[lr][0][2][1] -= 0.02f;

					ctl[lr][2][2][2] -=0.04f;
					ctl[lr][2][2][0] -= 0.02f;
					ctl[lr][2][2][1] -= 0.02f;

					ctl[lr][1][1][2] +=0.04f;

		} else if(ctl[lr][0][0][2] > -2 && ld) { 

					ctl[lr][0][0][2] -=0.04f;
					ctl[lr][0][0][0] -= 0.02f;
					ctl[lr][0][0][1] -= 0.02f;

					ctl[lr][2][0][2] -=0.04f;
					ctl[lr][2][0][0] += 0.02f;
					ctl[lr][2][0][1] -= 0.02f;

					ctl[lr][0][2][2] -= 0.04f;
					ctl[lr][0][2][0] -= 0.02f;
					ctl[lr][0][2][1] += 0.02f;

					ctl[lr][2][2][2] -=0.04f;
					ctl[lr][2][2][0] += 0.02f;
					ctl[lr][2][2][1] += 0.02f;

					ctl[lr][1][1][2] +=0.04f;
		} else {
			ld = !ld;
			movup = 1;
		}

	glutPostRedisplay();
}


static void
key(unsigned char k, int x, int y)
{
  switch (k) {
  case 27:  /* Escape */
    exit(0);
    break;
  

  default:
    return;
  }
  glutPostRedisplay();
}

/* Main Loop */
int
main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGB);
    glutCreateWindow(argv[0]);
    myinit();
    glutReshapeFunc(reshape);
    glutDisplayFunc(display);
    glutCreateMenu(menu);
    glutAddMenuEntry("solid/wire", 0);
//	glutAddMenuEntry("control on/off", 1);
    glutAttachMenu(GLUT_MIDDLE_BUTTON);
	

    glutMouseFunc(mouse);
    glutMotionFunc(motion);
    glutKeyboardFunc(key);
	glutIdleFunc(idle);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}