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

// Define a constant for the value of PI
#define GL_PI 3.1415f

static int MenuID, IdleMenu;
static int IdlePrint = 0;

GLfloat xRot = 0.0f;
GLfloat yRot = 0.0f;

GLfloat rotation = 0.0;
GLfloat fordulat = 5.0;

void BitmapText( GLfloat x, GLfloat y, char *string )
{
  int len, i;
  glRasterPos2f( x, y );
  len = (int) strlen ( string );
  for ( i = 0; i < len; i++ ){
    glutBitmapCharacter ( GLUT_BITMAP_HELVETICA_18, string[i] );
  }
}

void csonkakup(int n, double height, double radius, double top)
{
  int i;
  GLfloat angle;

  if(n < 3)
    n = 3;
  
  glBegin(GL_QUAD_STRIP);
  for(i = 0, angle = 0.0; i <= n; i++, angle += 2.0 * GL_PI / n)
  {

    if(i%2) {
      glColor3f(1.0, 0.0, 0.0);
    } else {
      glColor3f(0.0, 1.0, 0.0);
    }

      glVertex3f(radius * cos(angle), 0.0, radius * sin(angle));
      glVertex3f(top * cos(angle), height, top * sin(angle));
  }
  glEnd();
}

// Called to draw scene
void RenderScene(void)
{
  // Clear the window with current clearing color
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glColor3f(1.0, 1.0, 1.0);
  BitmapText(-20, 20, "X Y");
  BitmapText(-20, -20, "Billentyuk, F1, F2, Nyilak");

  glPushMatrix();
  glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  glRotatef(yRot, 0.0f, 1.0f, 0.0f);

  // >> Modellezo programresz

  csonkakup(16, 20, 8, 6);

  glPushMatrix();
  
  glTranslatef(0.0, 15.0, 0.0);

  glRotatef(rotation, 1.0, 0.0, 0.0);

  glColor3f(0.0, 1.0, 1.0);
  glPushMatrix();
    glScalef(20.0, 1.0, 1.0);
    glutSolidCube(1.0);
  glPopMatrix();

  glColor3f(0.0, 0.0, 1.0);
  glPushMatrix();
    glTranslatef(10.5, 0.0, 0.0);
    glScalef(1.0, 6.0, 20.0);
    glutSolidCube(1.0);
  glPopMatrix();

  glPopMatrix();

  // << Modellezo programresz

  glPopMatrix();
  
  // Flush drawing commands
  glutSwapBuffers();
}

// This function does any needed initialization on the rendering
// context. 
void SetupRC()
{
  glShadeModel(GL_FLAT);

  // Black background
  glClearColor(0.0f, 0.0f, 0.0f, 1.0f );
  glEnable(GL_DEPTH_TEST);
}

void SpecialKeys(int key, int x, int y)
{
  // ...
  int state;

  if(key == GLUT_KEY_UP)
    xRot-= 5.0f;
  
  if(key == GLUT_KEY_DOWN)
    xRot += 5.0f;
  
  if(key == GLUT_KEY_LEFT)
    yRot -= 5.0f;
  
  if(key == GLUT_KEY_RIGHT)
    yRot += 5.0f;
  
  if(xRot > 356.0f)
    xRot = 0.0f;
  
  if(xRot < 0.0f)
    xRot = 355.0f;
  
  if(yRot > 356.0f)
    yRot = 0.0f;
  
  if(yRot < -1.0f)
    yRot = 355.0f;

  if(key == GLUT_KEY_F1)
    fordulat += 1.0;

  if(key == GLUT_KEY_F2)
    fordulat -= 1.0;

  printf("Funkciobillentyu lenyomva, kodja %d, pozicio (%d,%d). ", key, x, y);
  state = glutGetModifiers();
  if(state & GLUT_ACTIVE_SHIFT)
    printf("SHIFT lenyomva. ");
  if(state & GLUT_ACTIVE_CTRL)
    printf("CTRL lenyomva. ");
  if(state & GLUT_ACTIVE_ALT)
    printf("ALT lenyomva. ");
  printf("\n");
  fflush(stdout);

  // Refresh the Window
  glutPostRedisplay();
}

void Keyboard(unsigned char key, int x, int y)
{
  // ...
  int state;

  printf("Billentyu lenyomva, kodja %c, pozicio (%d,%d). ", key, x, y);
  state = glutGetModifiers();
  if(state & GLUT_ACTIVE_SHIFT)
    printf("SHIFT lenyomva. ");
  if(state & GLUT_ACTIVE_CTRL)
    printf("CTRL lenyomva. ");
  if(state & GLUT_ACTIVE_ALT)
    printf("ALT lenyomva. ");
  printf("\n");
  fflush(stdout);

  glutPostRedisplay();
}

void Timer(int value)
{
  rotation += fordulat;
  if(rotation >= 360)
    rotation = 0.0;

  glutPostRedisplay();
  glutTimerFunc(100, Timer, value + 1);
}

void Idle()
{
  if(IdlePrint)
    printf("Idle esemeny.\n");

  glutPostRedisplay();
}

void ChangeSizeOrtho(int w, int h)
{
  GLfloat nRange = 25.0f;
  
  // Prevent a divide by zero
  if(h == 0)
    h = 1;
  
  // Set Viewport to window dimensions
  glViewport(0, 0, w, h);
  
  // Reset projection matrix stack
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  
  // Establish clipping volume (left, right, bottom, top, near, far)
  if (w <= h) 
    glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange, nRange);
  else 
    glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange, nRange);
  
  // Reset Model view matrix stack
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void ChangeSizePerspective(GLsizei w, GLsizei h)
{
  GLfloat fAspect;
  
  // Prevent a divide by zero
  if(h == 0)
    h = 1;
  
  // Set Viewport to window dimensions
  glViewport(0, 0, w, h);
  
  fAspect = (GLfloat)w/(GLfloat)h;
  
  // Reset coordinate system
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  
  // Produce the perspective projection
  gluPerspective(60.0f,    // fovy
		 fAspect,  // aspect
		 10.0,     // zNear
		 100.0     // zFar
		 );
  gluLookAt(0.0, 0.0, 50.0, // eye
	    0.0, 0.0, 0.0,  // center
	    0.0, 1.0, 0.0   // up
	    );
  
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void ProcessMenu(int value)
{
  switch(value)
    {
    case 1:
      printf("1. menupont kivalasztva.\n");
      break;
      
    case 2:
      printf("2. menupont kivalasztva.\n");
      break;
      
    case 3:
      printf("Idle kiiratas bekapcsolva.\n");
      IdlePrint = 1;
      break;

    case 4:
      printf("Idle kiiratas kikapcsolva.\n");
      IdlePrint = 0;
      break;
      
    case 5:
      exit(0);

    default:
      break;
    }
  
  glutPostRedisplay();
}

int main(int argc, char* argv[])
{
  // >> Inicializalas

  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  //glutInitWindowSize(300, 300);
  glutCreateWindow("GLUT Alap");

  // << Inicializalas

  // >> Callback fuggvenyek

  glutReshapeFunc(ChangeSizeOrtho); // Parhuzamos vetites
  //glutReshapeFunc(ChangeSizePerspective); // Perspektiv vetites

  glutSpecialFunc(SpecialKeys);
  glutKeyboardFunc(Keyboard);
  glutDisplayFunc(RenderScene);
  glutTimerFunc(1000, Timer, 1); // 1 mp mulva meghivodik a Timer() fuggveny
  //glutIdleFunc(Idle); // Idle(), ha nem tortenik semmi
  
  // << Callback fuggvenyek

  // >> Menu

  IdleMenu = glutCreateMenu(ProcessMenu);
  glutAddMenuEntry("Idle kiiratas bekapcsolasa", 3);
  glutAddMenuEntry("Idle kiiratas kikapcsolasa", 4);

  MenuID = glutCreateMenu(ProcessMenu);
  glutAddMenuEntry("1. menupont", 1);
  glutAddMenuEntry("2. menupont", 2);
  glutAddSubMenu("Idle fuggveny", IdleMenu);
  glutAddMenuEntry("Kilepes", 5);
  glutAttachMenu(GLUT_RIGHT_BUTTON);

  // << Menu

  SetupRC();
  glutMainLoop();
  
  return 0;
}