/*
 *
 *  OpenGL, glut を使った Lorenz方程式の解曲線を描画するデモ・プログラム   
 *                                                  ver.0.11 (1998/12/2)
 */

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

#define PARALLAX 0.2
#define DISTANCE 8.0

#define DATA_SIZE 10000
#define CARS 6

static double lane[DATA_SIZE][3];
static double lanecolor[DATA_SIZE][3];
static double cars[CARS][3],carsp[CARS][3];
static int carlap[CARS];

static int zoom=8;                 /* ズームのパラメーター */
static double vht=0.3;             /* 視点の高さ */
static int car_num=0;              /* 視点を設定する車の番号 */
static int vall=1;                 /* 視点の切り替えスイッチ */

static int vp,vh,zm;               /* menu ID's */

void solv_de(u,v) /* Lorenz方程式の差分化方程式の繰り返し計算 */
     double u[3],v[3];
{
  static double dt = 0.005;	/* 時間間隔 */

  v[0] = u[0] + dt * (10.0 * (u[1] - u[0]));
  v[1] = u[1] + dt * (28.0 * u[0] - u[1] - u[0] * u[2]);
  v[2] = u[2] + dt * (-2.666666667 * u[2] + u[0] * u[1]);
}

void make_lane(void) /* 解曲線のデータ作成 */
{
  int  i,j;
  double v1[3],v2[3];
  GLdouble c1,c2,c3;

  v1[0] = 2.0; v1[1] = 2.0; v1[2] = 2.0; /* 初期値 */

  for(i=0; i<300; i++) {	/* 初期の空回し */
    solv_de(v1,v2);
    for (j=0; j<3; j++) v1[j] = v2[j];
  }
    
  for(i=0; i < DATA_SIZE; i++) { /* データを計算して保存 */
    solv_de(v1,v2);

    lane[i][0] = v2[0] + v2[1];
    lane[i][1] = (v2[0] - v2[1]) / 10.0;
    lane[i][2] = v2[2];

    for (j=0; j<3; j++) v1[j] = v2[j];

    c1 = (lane[i][0]+lane[i][1]) / 100.0 + 0.5;
    c2 = 4.0 * (double)i * (DATA_SIZE - i) / DATA_SIZE / DATA_SIZE;
    c3 = lane[i][2] / 100.0;
    lanecolor[i][0] = c2*c3;
    lanecolor[i][1] = c2*(1.0-c1);
    lanecolor[i][2] = c2*c1;
  }
}

void move_cars(void)
{
  int i;
  double v1[3],v2[3];

  for(i=0; i<CARS; i++) {
    carsp[i][0] = cars[i][0];
    carsp[i][1] = cars[i][1];
    carsp[i][2] = cars[i][2];
    v1[0] = cars[i][0] / 2.0 + cars[i][1] * 5.0;
    v1[1] = cars[i][0] / 2.0 - cars[i][1] * 5.0;
    v1[2] = cars[i][2];
    solv_de(v1,v2);
    cars[i][0] = v2[0] + v2[1];
    cars[i][1] = (v2[0] - v2[1]) / 10.0;
    cars[i][2] = v2[2];

    if ((cars[i][0] < -16.97 || cars[i][0] > 16.97) 
	&& carsp[i][2] < 27.0 && cars[i][2] > 27.0 ) carlap[i]++;
  }
}

void init_cars(void)  /* 解の初期値設定 */
{
  int i;
  double r;

  for(i=0; i<CARS; i++) {
    r = (double) rand() / (RAND_MAX+1) - 0.5;
    cars[i][0] = r * 10.0;
    cars[i][1] = 0.0;
    cars[i][2] = 40.0;

    carlap[i]=0;
  }
  move_cars();
}

void init(void)
{
  time_t tp;
  char time_c[100];

  glClearColor(0.0, 0.0, 0.0, 0.0);
  glShadeModel(GL_SMOOTH);
  glEnable(GL_DEPTH_TEST);

  srand ((unsigned int) time(&tp));

  make_lane();

  init_cars();
}

void idle(void)
{
  move_cars();

  glutPostRedisplay();
}

void set_sight(double offset)
{
  int i;
  double u1[3], ur[3], ue[3];
  double rr;

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
#ifdef STEREO
  glTranslated(offset, 0.0, 0.0);
  glRotated(atan2(offset, DISTANCE) * 180.0 / 3.1415926536, 0.0, 1.0, 0.0);
#endif
  if (vall == 1) {		/* 視点を上方遠方に固定 */
    gluLookAt(0.0,100.0,30.0, 0.0,0.0,30.0, 0.0,0.0,1.0);
  } else {
    for(i=0; i<3; i++) {
      u1[i] = carsp[car_num][i];
      ur[i] = cars[car_num][i] - u1[i];
    }
    rr = sqrt(ur[0]*ur[0]+ur[1]*ur[1]+ur[2]*ur[2]);
    for(i=0; i<3; i++)
      ue[i] = u1[i] - (double)zoom * ur[i] / rr;
    ue[1] += (double)(zoom * vht);
    gluLookAt(ue[0],ue[1],ue[2], u1[0],u1[1],u1[2], 0.0,1.0,0.0);
  }
}

void set_light(void)
{
  GLfloat light_ambient[] = { 0.2,0.2,0.2,1.0 };
  GLfloat light_position0[] = {  17.0, 50.0, 27.0, 1.0 };
  GLfloat light_position1[] = { -17.0,-50.0, 27.0, 1.0 };
  GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };

  glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
  glLightfv(GL_LIGHT1, GL_AMBIENT, light_ambient);
  glLightfv(GL_LIGHT0, GL_POSITION, light_position0);
  glLightfv(GL_LIGHT1, GL_POSITION, light_position1);
  glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
  glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse);

  glEnable(GL_LIGHT0);
  glEnable(GL_LIGHT1);
}

void display(void)
{
  int i;
  GLfloat mat_diffuse1[] = {1.0, 1.0, 1.0, 1.0};
  GLfloat mat_diffuse[6][4]= {{1.0, 0.2, 0.2, 1.0},
                                {0.2, 1.0, 0.2, 1.0},
                                {0.2, 0.2, 1.0, 1.0},
                                {1.0, 1.0, 0.2, 1.0},
                                {1.0, 0.2, 1.0, 1.0},
                                {0.2, 1.0, 1.0, 1.0}};

#ifdef STEREO
#ifdef CRM
  glDrawBuffer(GL_BACK_RIGHT);
#else
  glViewport(0, 0, 1280, 492);
#endif
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  set_sight(-PARALLAX);
  glNewList(1, GL_COMPILE_AND_EXECUTE);
#else
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  set_sight(0.0);
#endif

  set_light();

  /* 解軌道を点線で表示 */
  glBegin(GL_LINE_STRIP);
  for(i=0; i < DATA_SIZE; i++) {
    glColor3dv(lanecolor[i]);
    glVertex3dv (lane[i]);
  }
  glEnd();

  glEnable(GL_LIGHTING);

  /* 解軌道上の点をトーラスで表示 */
  for(i=0; i<CARS; i++) {
    glPushMatrix();
    glTranslated(cars[i][0],cars[i][1],cars[i][2]);
    glRotated(90.0, 1.0, 0.0, 0.0);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse[i % 6]);
    if (vall == 0) glutSolidTorus(0.04, 0.2, 4, 3+carlap[i]/5);
    else glutSolidSphere(0.4, 10,10);
    glPopMatrix();
  }

  /* 方程式の2個の平衡点を球で表示 */
  glPushMatrix();
  glTranslated(16.97, 0.0, 27.0);
  glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse1);
  glutSolidSphere(0.2*(1+vall*2),20,20);
  glPopMatrix();
  glPushMatrix();
  glTranslated(-16.97, 0.0, 27.0);
  glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse1);
  glutSolidSphere(0.2*(1+vall*2),20,20);
  glPopMatrix();

  glDisable(GL_LIGHTING);

#ifdef STEREO
  glEndList();
#ifdef CRM
  glDrawBuffer(GL_BACK_LEFT);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
#else
  glViewport(0, 532, 1280, 492);
#endif
  set_sight(PARALLAX);
  glCallList(1);
#endif

  glutSwapBuffers();
}


void reshape(int w, int h)
{
#if !defined(STEREO) || defined(CRM)
  glViewport(0, 0, (GLsizei) w, (GLsizei) h);
#endif
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(40.0, (GLfloat)w/(GLfloat)h, 1.0, 500.0);
}

void quit(void)
{
  int i;
  double x,y,r;

#if defined(STEREO) && !defined(CRM)
  system("/usr/gfx/setmon -n 60HZ");
#endif

  printf("Laps of the Tori:\n");
  for(i=0; i<CARS; i++) {
    if (cars[i][0] > 0.0) x =   cars[i][0] - 16.97;
    else x = - cars[i][0] - 16.97;
    y = cars[i][2] - 27.0;
    r = atan2(y,x) / 6.2832;
    if (r < 0.0) r = r+1.0;

    printf("%1d : %3d laps and %3d%%\n", i+1,carlap[i],(int)(r*100));
  }
  exit(0);
}

void keyboard(unsigned char key, int x, int y)
{
  switch(key) {
  case 27:			/* [ESC] プログラムの終了 */
    quit();
    break;
  case 's':			/* アニメーション一時停止 */
    glutIdleFunc(NULL);
    break;
  case 'g':			/* アニメーション開始 */
    glutIdleFunc(idle);
    break;
  case ' ':			/* (停止時に)1コマ進める */
    idle();
    break;
  case '0':			/* 視点を上方遠方にする */
    vall = 1;
    glutPostRedisplay();
    break;
  case '1':			/* 視点を1番の車にする */
    vall = 0;
    car_num = 0;
    glutPostRedisplay();
    break;
  case '2':			/* 視点を2番の車にする */
    vall = 0;
    car_num = 1;
    glutPostRedisplay();
    break;
  case '3':			/* 視点を3番の車にする */
    vall = 0;
    car_num = 2;
    glutPostRedisplay();
    break;
  case '4':			/* 視点を4番の車にする */
    vall = 0;
    car_num = 3;
    glutPostRedisplay();
    break;
  case '5':			/* 視点を5番の車にする */
    vall = 0;
    car_num = 4;
    glutPostRedisplay();
    break;
  case '6':			/* 視点を6番の車にする */
    vall = 0;
    car_num = 5;
    glutPostRedisplay();
    break;
  case 'u':			/* 視点を上にずらす */
    if (vall == 0) {
      vht += 0.2; if(vht > 1.1) vht = 1.1;
      glutPostRedisplay();
    }
    break;
  case 'd':			/* 視点を下にずらす */
    if (vall == 0) {
      vht -= 0.2; if (vht < -1.1) vht = -1.1;
      glutPostRedisplay();
    }
    break;
  case '+':			/* ズームイン */
    if (vall == 0) {
      zoom = zoom / 2; if (zoom < 2) zoom = 2;
      glutPostRedisplay();
    }
    break;
  case '-':			/* ズームアウト */
    if (vall == 0) {
      zoom = zoom * 2; if (zoom > 128) zoom = 128;
      glutPostRedisplay();
    }
    break;
  }
}

void param_vp(int sel)
{
  switch(sel) {
  case 9: vall = 1; break;
  case 1: vall = 0; car_num = 0; break;
  case 2: vall = 0; car_num = 1; break;
  case 3: vall = 0; car_num = 2; break;
  case 4: vall = 0; car_num = 3; break;
  case 5: vall = 0; car_num = 4; break;
  case 6: vall = 0; car_num = 5; break;
  }
  glutPostRedisplay();
  if (vall == 1) {
    glutChangeToMenuEntry(8,"",9);
    glutChangeToMenuEntry(9,"",9);
  } else {
    glutChangeToSubMenu(8,"Height",vh);
    glutChangeToSubMenu(9,"Zoom",zm);
  }
}

void param_vh(int sel)
{
  switch(sel) {
  case  1: vht =  1.1; break;
  case  2: vht =  0.9; break;
  case  3: vht =  0.7; break;
  case  4: vht =  0.5; break;
  case  5: vht =  0.3; break;
  case  6: vht =  0.1; break;
  case  7: vht = -0.1; break;
  case  8: vht = -0.3; break;
  case  9: vht = -0.5; break;
  case 10: vht = -0.7; break;
  case 11: vht = -0.9; break;
  case 12: vht = -1.1; break;
  }
  glutPostRedisplay();
}

void param_zm(int sel)
{
  switch(sel) {
  case  1: zoom =   2; break;
  case  2: zoom =   4; break;
  case  3: zoom =   8; break;
  case  4: zoom =  16; break;
  case  5: zoom =  32; break;
  case  6: zoom =  64; break;
  case  7: zoom = 128; break;
  }
  glutPostRedisplay();
}

void param_al(int sel)
{
  switch(sel) {
  case  1:			/* Pause */
    glutIdleFunc(NULL);
    glutChangeToMenuEntry(2,"Restart",2);
    glutChangeToMenuEntry(3,"Forward",3);
    break;
  case  2:			/* Restart */
    glutIdleFunc(idle);
    glutChangeToMenuEntry(2,"Pause",1);
    glutChangeToMenuEntry(3,"",4);
    break;
  case  3:			/* Forward */
    idle();
    break;
  case  4:			/* Nothing */
    break;
  case  9:			/* Quit */
    quit();
    break;
  }
  glutPostRedisplay();
}

void menu(void)
{
  vh = glutCreateMenu(param_vh);
  glutAddMenuEntry("High",1);
  glutAddMenuEntry("/\\",2);
  glutAddMenuEntry(" .",3);
  glutAddMenuEntry(" .",4);
  glutAddMenuEntry(" -",5);
  glutAddMenuEntry(" .",6);
  glutAddMenuEntry(" .",7);
  glutAddMenuEntry(" .",8);
  glutAddMenuEntry(" .",9);
  glutAddMenuEntry(" .",10);
  glutAddMenuEntry("\\/",11);
  glutAddMenuEntry("Low",12);

  zm = glutCreateMenu(param_zm);
  glutAddMenuEntry("Near",1);
  glutAddMenuEntry("/\\",2);
  glutAddMenuEntry(" -",3);
  glutAddMenuEntry(" .",4);
  glutAddMenuEntry(" .",5);
  glutAddMenuEntry("\\/",6);
  glutAddMenuEntry("Far",7);

  vp = glutCreateMenu(param_vp);
  glutAddMenuEntry("All",9);
  glutAddMenuEntry("Follow Red",1);
  glutAddMenuEntry("Follow Green",2);
  glutAddMenuEntry("Follow Blue",3);
  glutAddMenuEntry("Follow Yellow",4);
  glutAddMenuEntry("Follow Magenta",5);
  glutAddMenuEntry("Follow Cyan",6);
  glutAddMenuEntry("",7);
  glutAddMenuEntry("",7);

  glutCreateMenu(param_al);
  glutAddSubMenu("View Position",vp);
  glutAddMenuEntry("Restart",2);
  glutAddMenuEntry("Forward",3);
  glutAddMenuEntry("Quit",9);

  glutAttachMenu(GLUT_LEFT_BUTTON);
}

int main(int argc, char *argv[])
{
#if defined(STEREO) && !defined(CRM)
  system("/usr/gfx/setmon -n STR_RECT");
#endif

  glutInitWindowSize(480,360);
  glutInitWindowPosition(50,50);

  glutInit(&argc, argv);
#ifdef CRM
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STEREO);
#else
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
#endif
  glutCreateWindow("Race on the Lorenz Equation");

  init();
  menu();

  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
  glutKeyboardFunc(keyboard);
  glutIdleFunc(NULL);
#if defined(STEREO) && !defined(CRM)
  glutFullScreen();
#endif
  glutMainLoop();

  return 0;
}