/* Auteur: Nicolas JANEY              */
/* nicolas.janey@univ-fcomte.fr       */
/* Avril 2001                         */
/* 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"

static GLfloat pts[6][3] = { 
  { 1.0,-3.0,-3.0},{-2.0,2.0,3.0}, 
  { 2.0,3.0,-2.0},{ -3.0,0.0,-4.0}, 
  { -2.0,-3.0,2.0},{ 3.0,-4.0,-1.0}}; 
static int aff = 0 ;
static int pt = 0 ;
static int disc = 30 ;
  
struct coord_3D {
  GLfloat x,y,z ; } ;
struct polygone {
  int n ;
  coord_3D *p ; } ;
typedef float matrice[4][4] ;

void pixel(float x,float y,float z) {
  glVertex3f(x,y,z); 
}

void lisse(coord_3D *p,int n,matrice m) { 
  int i,j,k ;
  float tt[4],ttt[4],x,y,z ;
  for ( 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 ; }
    pixel(x,y,z) ; }
}

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

polygone pl = { 6,(coord_3D *) &pts[0][0] } ;
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 } ;
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 myinit(void) { 
  glClearColor(0.0,0.0,0.0,1.0); 
  glMap1f(GL_MAP1_VERTEX_3,0.0,1.0,3,6,&pts[0][0]); 
  glEnable(GL_MAP1_VERTEX_3); 
  glShadeModel(GL_FLAT); 
  glDepthFunc(GL_LESS);
} 
  
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) {
  glutInit(&argc,argv);
  glutInitDisplayMode(GLUT_RGBA|GLUT_DEPTH|GLUT_DOUBLE);
  glutInitWindowSize(300,300); 
  glutInitWindowPosition(50,50); 
  glutCreateWindow("Courbe B-Spline par morceaux"); 
  myinit(); 
  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);
}