/* Auteur: Nicolas JANEY                        */
/* nicolas.janey@univ-fcomte.fr                 */
/* Octobre 2010                                 */
/*                                              */
/* Un programme OpenGL d'animation automatique  */
/* d'un ensemble de particules ponctuelles      */
/* modelisant une cascade                       */

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

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

#include "Position3D.h"
#include "Direction3D.h"
#include "Particule.h"

static GLint win = 0;
static int program = 2;

static GLint cascadeArraySize = 25000;

static double inc = 0.02;
static double time = 0.0;

class Particule *particules; 

static void checkError(int line) {
  GLenum err = glGetError();
  if (err) {
    printf("GL Error %s (0x%x) at line %d\n",
           gluErrorString(err),(int) err,line); }
}

static void createCascade(GLint size) {
  particules = new Particule[cascadeArraySize]();
  for ( int i = 0 ; i < cascadeArraySize ; i++ ) {
    particules[i].init(i*15.0/cascadeArraySize);}
}

static void drawCascade(void) {
  glPointSize(1.0);
  glBegin(GL_POINTS);
  for ( int i = 0 ; i < cascadeArraySize ; i++ ) {
    if ( time >= particules[i].startIni ) {
      glVertex3dv((double *) &(particules[i].p)); } }
  glEnd();
  static int img = 0;
  printf("%8.2lf : %5d\n",time,img);
  img++;
}

/* Fonction executee lors d'un changement       */
/* de la taille de la fenetre OpenGL            */

void reshape(int x,int y) {
  glViewport(0,0,x,y); 
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(60.0F,(float) x/y,15.0,5000.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  gluLookAt(10.0,-20.0,50.0,10.0,-20.0,0.0,0.0,1.0,0.0);
}

static void display(void) {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();
  drawCascade();
  glTranslatef(0.0F,-20.0F,0.0F);
  glPopMatrix();
  glFlush();
  checkError(__LINE__);
  glutSwapBuffers();
}

static void cleanUp(void) {
  delete [] particules;
}

static void idle(void) {
  time += inc;
  for ( int i = 0 ; i < cascadeArraySize ; i++ ) {
    particules[i].update(time); }
  glutPostRedisplay();
}

/* Fonction executee lors de l'appui            */
/* d'une touche alphanumerique du clavier       */

void key(unsigned char key,int x,int y) {
  static int anim = 1;
  switch ( key ) {
    case 0x0D : anim = !anim;
                glutIdleFunc(anim ? idle : NULL);
                break;
    case 43   : time += inc;
                for ( int i = 0 ; i < cascadeArraySize ; i++ ) {
                  particules[i].update(time); }
                glutPostRedisplay();
                break;
    case 45   : time -= inc;
                if ( time < 0.0F )
                  time = 0.0F;
                for ( int i = 0 ; i < cascadeArraySize ; i++ ) {
                  particules[i].update(time); }
                glutPostRedisplay();
                break;
    case 0x1B : cleanUp();
                exit(0);
                break; }
}

static void init(void) {
  createCascade(cascadeArraySize);
  glClearColor(0.4F,0.4F,0.8F,0.0F);
  glEnable(GL_DEPTH_TEST);
  glColor3f(1.0F,1.0F,1.0F);
}

int main(int argc, char *argv[]) {
  glutInit(&argc,argv);
  glutInitWindowPosition(10,10);
  glutInitWindowSize(240,480);
  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
  win = glutCreateWindow(argv[0]);
  glutReshapeFunc(reshape);
  glutKeyboardFunc(key);
  glutDisplayFunc(display);
  glutIdleFunc(idle);
  init();
  glutMainLoop();
  return(0);
}