/* Auteur: Nicolas JANEY              */
/* nicolas.janey@univ-fcomte.fr       */
/* Fevrier 2019                       */
/* Illustration de la generation      */
/* d'une courbe B-Spline par morceaux */

#include <math.h>
#include <stdio.h>

#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/glu.h>

#include "ModuleCouleurs.h"
#include "ModuleFont.h"
#include "ModuleManipulateur.h"
#include "ModuleMenus.h"
#include "ModuleReshape.h"

struct coord_3D {
  GLfloat x = 0.0F;
  GLfloat y = 0.0F;
  GLfloat z = 0.0F;
  GLfloat w = 1.0F; };

struct polygone {
  int n = 0;
  coord_3D *p = NULL; };

typedef struct coord_3D coord_3D;
typedef struct polygone polygone;
typedef float matrice[4][4];

static GLfloat pts[6][4] = { 
  {  1.0F,-3.0F,-3.0F, 1.0F },
  { -2.0F, 2.0F, 3.0F, 1.0F }, 
  {  2.0F, 3.0F,-2.0F, 1.0F },
  { -3.0F, 0.0F,-4.0F, 1.0F }, 
  { -2.0F,-3.0F, 2.0F, 1.0F },
  {  3.0F,-4.0F,-1.0F, 1.0F } };

static int aff = 0;
static int pt = 0;
static int disc = 30;
 
void point(float x,float y,float z) {
  glVertex3f(x,y,z);
}

void morceauBSpline(coord_3D *p,int n,matrice m) { 
  int j,k;
  float tt[4],ttt[4],x,y,z;
  for ( int i = 0 ; i < n ; i++ ) {
    float t =(float) i/(n-1);
    tt[0] = t*t*t;
    tt[1] = t*t;
    tt[2] = t;
    tt[3] = 1;
    for ( j = 0 ; j < 4 ; j++ )
      for ( k = 0,ttt[j] = 0 ; k < 4 ; k++ )
        ttt[j] += tt[k] * m[k][j];
    x = y = z = 0;
    for ( j = 0 ; j < 4 ; j++ ) {
      x += ttt[j] * p[j].x;
      y += ttt[j] * p[j].y;
      z += ttt[j] * p[j].z; }
    point(x,y,z); }
}

void b_spline(polygone *p,matrice m,int n) { 
  for ( int i = 0 ; i < p->n-3 ; i++ )
    morceauBSpline(&p->p[i],n,m);
}

static polygone pl;
static matrice m1 = { -0.1666666F, 0.5F,      -0.5F,      0.1666666F,
                       0.5F      ,-1.0F,       0.5F,      0.0F,
                      -0.5F      , 0.0F,       0.5F,      0.0F,
                       0.1666666F, 0.6666666F, 0.1666666F,0.0F };
static matrice m2 = { -0.5F, 1.5F,-1.5F, 0.5F,
                       1.0F,-2.5F, 2.0F,-0.5F,
                      -0.5F, 0.0F, 0.5F, 0.0F,
                       0.0F, 1.0F, 0.0F, 0.0F};

void display(void) { 
  int i;
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  glEnable(GL_DEPTH_TEST);
  manipulateurSouris();
  manipulateurClavier();
  glColor4fv(couleurBlanc());
  glBegin(GL_LINE_STRIP);
  for ( i = 0 ; i < 6 ; i++ ) 
    glVertex3fv(&pts[i][0]);
  glEnd();
  glPointSize(5.0);
  glBegin(GL_POINTS);
  for ( i = 0 ; i < 6 ; i++ ) {
    glColor4fv((i == pt) ? couleurRouge() : couleurJaune());
    glVertex3fv(&pts[i][0]); }
  glEnd();
  glColor4fv(couleurMagenta());
  glPointSize(3.0);
  glBegin(GL_POINTS);
  b_spline(&pl,( aff ) ? m1 : m2,disc);
  glEnd();
  glDisable(GL_DEPTH_TEST);
  for ( i = 0 ; i < 6 ; i++ )  {
    glColor4fv((i == pt) ? couleurRouge() : couleurJaune());
    placeFontCursor(pts[i][0]+0.3F,pts[i][1]+0.3F,pts[i][2]+0.3F);
    simpleBitmapOutput("%d",i); }
  glPopMatrix();
  glPushMatrix();
  glColor4fv(couleurBlanc());
  placeFontCursor(getXmin()+0.3F,getYmin()+0.8F,0.0);
  simpleBitmapOutput("%s",((aff) ? "NRUBS" : "Catmull Rom"));
  glPopMatrix();
  glFlush();
  glutSwapBuffers();
} 

void init(void) { 
  glClearColor(0.0,0.0,0.0,1.0);
} 
  
void special(int k, int x, int y) {
  switch (k) {
    case GLUT_KEY_UP    : pl.p[pt].y += 0.1F;
                          glutPostRedisplay();
                          break;
    case GLUT_KEY_DOWN  : pl.p[pt].y -= 0.1F;
                          glutPostRedisplay();
                          break;
    case GLUT_KEY_LEFT  : pl.p[pt].x -= 0.1F;
                          glutPostRedisplay();
                          break;
    case GLUT_KEY_RIGHT : pl.p[pt].x += 0.1F;
                          glutPostRedisplay();
                          break; }
}

void key(unsigned char key,int x,int y) {
  if ( keyManipulateur(key,x,y) )
    glutPostRedisplay();
    else
    switch ( key ) {
      case 'd'  : pl.p[pt].z -= 0.1F;
                  glutPostRedisplay();
                  break;
      case 'D'  : pl.p[pt].z += 0.1F;
                  glutPostRedisplay();
                  break;
      case 43   : disc++;
                  glutPostRedisplay();
                  break;
      case 45   : disc--;
                  if ( disc < 3 )
                    disc = 3;
                  glutPostRedisplay();
                  break;
      case 0x0D : aff = 1-aff;
                  glutPostRedisplay();
                  break;
      case 32   : pt = pt+1;
                  if ( pt == 6 )
                    pt = 0;
                  glutPostRedisplay();
                  break; }
}

int main(int argc,char **argv) {

  pl.n = 6;
  pl.p =(coord_3D *) &pts[0][0];

  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(300,300);
  glutInitWindowPosition(50,50);
  glutCreateWindow("Courbe B-Spline par morceaux");
  init();
  creationMenuBasique();
  setParametresOrthoBasique(-5.0,5.0,-5.0,5.0,-500.0,500.0);
  setManipulateurDistance(1.0F);
  glutReshapeFunc(reshapeOrthoBasique);
  glutKeyboardFunc(key);
  glutSpecialFunc(special);
  glutMotionFunc(motionBasique);
  glutMouseFunc(sourisBasique);
  glutDisplayFunc(display);
  glutMainLoop();
  return(0);
}