/********************************************************************

  File:          bus.cc
  Author:        Dana Vrajitoru

  Description:   A class handling a bus moving around.           
  Project:       A sprite moving through a maze application.

  Last updated:  February 10, 2011.

********************************************************************/

#include <GL/glut.h>
#include <cstdlib>
#include <cmath>
#include "bus.h"

// Returns the opposite of a given direction.
Direction opposite(Direction w)
{
  switch (w) {
  case north:
    return south;
  case south:
    return north;
  case east:
    return west;
  case west:
    return east;
  }
}

// Draws a polygon with given array of coordinates,
void polygon(GLfloat coords[][2], float offx, float offy, int n)
{
  glBegin(GL_POLYGON);
  for (int i=0; i<n; i++)
    glVertex2f(coords[i][0]+offx, coords[i][1]+offy);
  glEnd();
}

// Default constructor. Not much to do.Everything will be done in the
// init function.
Bus::Bus()
{
  x = y = 0;
  orient = north;
}

// Draw the object and store it in the display list. We also need to
// be able to give it an initial position.
void Bus::init(float posx, float posy)
{
  GLfloat frame_coords[8][2] = {{0.2, 0.1}, {0.2, 0.6}, {0.25, 0.65},
                                {0.45, 0.65}, {0.5, 0.6}, {0.5, 0.1},
                                {0.45, 0.05}, {0.25, 0.05}};
  GLfloat wheel_coords[6][2] = {{0.2, 0.15}, {0.17, 0.15}, {0.15, 0.17},
                                {0.15, 0.23}, {0.17, 0.25}, {0.2, 0.25}};
  GLfloat window_coords[4][2] = {{0.25, 0.15}, {0.25, 0.25}, 
                                 {0.45, 0.25}, {0.45, 0.15}};
  int i;

  // start a new list with the id of the bus but do not display it
  // right away.
  glNewList(busid, GL_COMPILE);

  // yellow frame
  glColor3f(1.0, 1.0, 0.0);
  polygon(frame_coords, -0.35, -0.35, 8);

  // red wheels
  glColor3f(1.0, 0.2, 0.4);
  polygon(wheel_coords, -0.35, -0.35, 6);
  // and a second one up from the first one
  polygon(wheel_coords, -0.35, -0.05, 6);

  // blue windows
  glColor3f(0.2, 0.3, 0.8);
  polygon(window_coords, -0.35, -0.35, 4);
  glColor3f(0.4, 0.5, 1.0);
  polygon(window_coords, -0.35, -0.05, 4);

  glEndList();
  x = posx;
  y = posy;
}

// Move the bus from the current position by one unit in the given
// direction
void Bus::move(Direction where)
{
  orient = where;
  switch (orient) {
  case north:
    y += 1;
    break;
  case south:
    y -= 1;
    break;
  case east:
    x += 1;
    break;
  case west:
    x -= 1;
    break;
  }
}

// Draw the bus at given coordinates by just applying some
// transformations and calling the display list.
void Bus::draw()
{
  glPushMatrix();
  glTranslatef(x+0.5, y+0.5, 0);
  float angle = int(orient)*90.0;
  if (angle != 0.0) 
    glRotatef(angle, 0, 0, 1.0); // rotation around Oz.
  glCallList(busid);
  glPopMatrix();
}