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

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

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

GLfloat xRot = 20.0f;
GLfloat yRot = 340.0f;
GLfloat rot1 = 0.0f;
int rot1sign = 1;

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

  // >> Modellezo programresz

  glPushMatrix();
  glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  glRotatef(yRot, 0.0f, 1.0f, 0.0f);
 
  glColor3f(1.0, 0.0, 0.0);
  glBegin(GL_LINES);
  glVertex3f(-30.0, 0.0, 0.0);
  glVertex3f(30.0, 0.0, 0.0);
  glVertex3f(0.0, -30.0, 0.0);
  glVertex3f(0.0, 30.0, 0.0);
  glVertex3f(0.0, 0.0, -30.0);
  glVertex3f(0.0, 0.0, 30.0);
  glEnd();
  

  // >>

  glPushMatrix();

  glColor3f(0.0, 1.0, 0.0); 

  glRotatef( rot1, 0.0, 1.0, 0.0 );
  glScalef( 20.0, 3.0, 3.0 );

  glutSolidCube( 1.0 );

  glPopMatrix();

  // <<

  glPopMatrix();

  // << Modellezo programresz
  
  // Flush drawing commands
  glutSwapBuffers();
}

// This function does any needed initialization on the rendering
// context. 
void SetupRC()
{
  // Black background
  glClearColor(0.0f, 0.0f, 0.0f, 1.0f );
  glEnable(GL_DEPTH_TEST);
  glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
}

void SpecialKeys(int key, int x, int y)
{
  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;
  
  // 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)
{
  if( rot1sign == 1 )
    {
      rot1 += 1.0;

      if( rot1 > 30.0 )
	{
	  rot1 = 30.0;
	  rot1sign = -1;
	}
    }
  else
    {
      rot1 -= 1.0;

      if( rot1 < -30.0 )
	{
	  rot1 = -30.0;
	  rot1sign = 1;
	}
    }

  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(100, 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;
}