'''
主題：
我的世界1.0版本
'''
from __future__ import division
 
import sys
import math
import random
import time
 
from collections import deque
from pyglet import image
from pyglet.gl import *
from pyglet.graphics import TextureGroup
from pyglet.window import key, mouse
 
TICKS_PER_SEC = 60
 
# Size of sectors used to ease block loading.
SECTOR_SIZE = 16
 
WALKING_SPEED = 5
FLYING_SPEED = 15
 
GRAVITY = 20.0
MAX_JUMP_HEIGHT = 1.0 # About the height of a block.
# To derive the formula for calculating jump speed, first solve
# v_t = v_0 + a * t
# for the time at which you achieve maximum height, where a is the acceleration
# due to gravity and v_t = 0. This gives:
# t = - v_0 / a
# Use t and the desired MAX_JUMP_HEIGHT to solve for v_0 (jump speed) in
# s = s_0 + v_0 * t + (a * t^2) / 2
JUMP_SPEED = math.sqrt(2 * GRAVITY * MAX_JUMP_HEIGHT)
TERMINAL_VELOCITY = 50
 
PLAYER_HEIGHT = 2
 
if sys.version_info[0] >= 3:
 xrange = range
 
def cube_vertices(x, y, z, n):
 """ Return the vertices of the cube at position x, y, z with size 2*n.
 """
 return [
  x-n,y+n,z-n, x-n,y+n,z+n, x+n,y+n,z+n, x+n,y+n,z-n,  # top
  x-n,y-n,z-n, x+n,y-n,z-n, x+n,y-n,z+n, x-n,y-n,z+n,  # bottom
  x-n,y-n,z-n, x-n,y-n,z+n, x-n,y+n,z+n, x-n,y+n,z-n,  # left
  x+n,y-n,z+n, x+n,y-n,z-n, x+n,y+n,z-n, x+n,y+n,z+n,  # right
  x-n,y-n,z+n, x+n,y-n,z+n, x+n,y+n,z+n, x-n,y+n,z+n,  # front
  x+n,y-n,z-n, x-n,y-n,z-n, x-n,y+n,z-n, x+n,y+n,z-n,  # back
 ]
 
 
def tex_coord(x, y, n=4):
 """ Return the bounding vertices of the texture square.
 """
 m = 1.0 / n
 dx = x * m
 dy = y * m
 return dx, dy, dx + m, dy, dx + m, dy + m, dx, dy + m
 
 
def tex_coords(top, bottom, side):
 """ Return a list of the texture squares for the top, bottom and side.
 """
 top = tex_coord(*top)
 bottom = tex_coord(*bottom)
 side = tex_coord(*side)
 result = []
 result.extend(top)
 result.extend(bottom)
 result.extend(side * 4)
 return result
 
 
TEXTURE_PATH = 'texture.png'
 
GRASS = tex_coords((1, 0), (0, 1), (0, 0))
SAND = tex_coords((1, 1), (1, 1), (1, 1))
BRICK = tex_coords((2, 0), (2, 0), (2, 0))
STONE = tex_coords((2, 1), (2, 1), (2, 1))
 
FACES = [
 ( 0, 1, 0),
 ( 0,-1, 0),
 (-1, 0, 0),
 ( 1, 0, 0),
 ( 0, 0, 1),
 ( 0, 0,-1),
]
 
 
def normalize(position):
 """ Accepts `position` of arbitrary precision and returns the block
 containing that position.
 Parameters
 ----------
 position : tuple of len 3
 Returns
 -------
 block_position : tuple of ints of len 3
 """
 x, y, z = position
 x, y, z = (int(round(x)), int(round(y)), int(round(z)))
 return (x, y, z)
 
 
def sectorize(position):
 """ Returns a tuple representing the sector for the given `position`.
 Parameters
 ----------
 position : tuple of len 3
 Returns
 -------
 sector : tuple of len 3
 """
 x, y, z = normalize(position)
 x, y, z = x // SECTOR_SIZE, y // SECTOR_SIZE, z // SECTOR_SIZE
 return (x, 0, z)
 
 
class Model(object):
 
 def __init__(self):
 
  # A Batch is a collection of vertex lists for batched rendering.
  self.batch = pyglet.graphics.Batch()
 
  # A TextureGroup manages an OpenGL texture.
  self.group = TextureGroup(image.load(TEXTURE_PATH).get_texture())
 
  # A mapping from position to the texture of the block at that position.
  # This defines all the blocks that are currently in the world.
  self.world = {}
 
  # Same mapping as `world` but only contains blocks that are shown.
  self.shown = {}
 
  # Mapping from position to a pyglet `VertextList` for all shown blocks.
  self._shown = {}
 
  # Mapping from sector to a list of positions inside that sector.
  self.sectors = {}
 
  # Simple function queue implementation. The queue is populated with
  # _show_block() and _hide_block() calls
  self.queue = deque()
 
  self._initialize()
 
 def _initialize(self):
  """ Initialize the world by placing all the blocks.
  """
  n = 80  # 1/2 width and height of world
  s = 1  # step size
  y = 0  # initial y height
  for x in xrange(-n, n + 1, s):
for z in xrange(-n, n + 1, s):
 # create a layer stone an grass everywhere.
 self.add_block((x, y - 2, z), GRASS, immediate=False)
 self.add_block((x, y - 3, z), STONE, immediate=False)
 if x in (-n, n) or z in (-n, n):
  # create outer walls.
  for dy in xrange(-2, 3):self.add_block((x, y + dy, z), STONE, immediate=False)
 
  # generate the hills randomly
  o = n - 10
  for _ in xrange(120):
a = random.randint(-o, o)  # x position of the hill
b = random.randint(-o, o)  # z position of the hill
c = -1  # base of the hill
h = random.randint(1, 6)  # height of the hill
s = random.randint(4, 8)  # 2 * s is the side length of the hill
d = 1  # how quickly to taper off the hills
t = random.choice([GRASS, SAND, BRICK])
for y in xrange(c, c + h):
 for x in xrange(a - s, a + s + 1):
  for z in xrange(b - s, b + s + 1):if (x - a) ** 2 + (z - b) ** 2 > (s + 1) ** 2:
continueif (x - 0) ** 2 + (z - 0) ** 2 < 5 ** 2:
continueself.add_block((x, y, z), t, immediate=False)
 s -= d  # decrement side lenth so hills taper off
 
 def hit_test(self, position, vector, max_distance=8):
  """ Line of sight search from current position. If a block is
  intersected it is returned, along with the block previously in the line
  of sight. If no block is found, return None, None.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position to check visibility from.
  vector : tuple of len 3
The line of sight vector.
  max_distance : int
How many blocks away to search for a hit.
  """
  m = 8
  x, y, z = position
  dx, dy, dz = vector
  previous = None
  for _ in xrange(max_distance * m):
key = normalize((x, y, z))
if key != previous and key in self.world:
 return key, previous
previous = key
x, y, z = x + dx / m, y + dy / m, z + dz / m
  return None, None
 
 def exposed(self, position):
  """ Returns False is given `position` is surrounded on all 6 sides by
  blocks, True otherwise.
  """
  x, y, z = position
  for dx, dy, dz in FACES:
if (x + dx, y + dy, z + dz) not in self.world:
 return True
  return False
 
 def add_block(self, position, texture, immediate=True):
  """ Add a block with the given `texture` and `position` to the world.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position of the block to add.
  texture : list of len 3
The coordinates of the texture squares. Use `tex_coords()` to
generate.
  immediate : bool
Whether or not to draw the block immediately.
  """
  if position in self.world:
self.remove_block(position, immediate)
  self.world[position] = texture
  self.sectors.setdefault(sectorize(position), []).append(position)
  if immediate:
if self.exposed(position):
 self.show_block(position)
self.check_neighbors(position)
 
 def remove_block(self, position, immediate=True):
  """ Remove the block at the given `position`.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position of the block to remove.
  immediate : bool
Whether or not to immediately remove block from canvas.
  """
  del self.world[position]
  self.sectors[sectorize(position)].remove(position)
  if immediate:
if position in self.shown:
 self.hide_block(position)
self.check_neighbors(position)
 
 def check_neighbors(self, position):
  """ Check all blocks surrounding `position` and ensure their visual
  state is current. This means hiding blocks that are not exposed and
  ensuring that all exposed blocks are shown. Usually used after a block
  is added or removed.
  """
  x, y, z = position
  for dx, dy, dz in FACES:
key = (x + dx, y + dy, z + dz)
if key not in self.world:
 continue
if self.exposed(key):
 if key not in self.shown:
  self.show_block(key)
else:
 if key in self.shown:
  self.hide_block(key)
 
 def show_block(self, position, immediate=True):
  """ Show the block at the given `position`. This method assumes the
  block has already been added with add_block()
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position of the block to show.
  immediate : bool
Whether or not to show the block immediately.
  """
  texture = self.world[position]
  self.shown[position] = texture
  if immediate:
self._show_block(position, texture)
  else:
self._enqueue(self._show_block, position, texture)
 
 def _show_block(self, position, texture):
  """ Private implementation of the `show_block()` method.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position of the block to show.
  texture : list of len 3
The coordinates of the texture squares. Use `tex_coords()` to
generate.
  """
  x, y, z = position
  vertex_data = cube_vertices(x, y, z, 0.5)
  texture_data = list(texture)
  # create vertex list
  # FIXME Maybe `add_indexed()` should be used instead
  self._shown[position] = self.batch.add(24, GL_QUADS, self.group,
('v3f/static', vertex_data),
('t2f/static', texture_data))
 
 def hide_block(self, position, immediate=True):
  """ Hide the block at the given `position`. Hiding does not remove the
  block from the world.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position of the block to hide.
  immediate : bool
Whether or not to immediately remove the block from the canvas.
  """
  self.shown.pop(position)
  if immediate:
self._hide_block(position)
  else:
self._enqueue(self._hide_block, position)
 
 def _hide_block(self, position):
  """ Private implementation of the 'hide_block()` method.
  """
  self._shown.pop(position).delete()
 
 def show_sector(self, sector):
  """ Ensure all blocks in the given sector that should be shown are
  drawn to the canvas.
  """
  for position in self.sectors.get(sector, []):
if position not in self.shown and self.exposed(position):
 self.show_block(position, False)
 
 def hide_sector(self, sector):
  """ Ensure all blocks in the given sector that should be hidden are
  removed from the canvas.
  """
  for position in self.sectors.get(sector, []):
if position in self.shown:
 self.hide_block(position, False)
 
 def change_sectors(self, before, after):
  """ Move from sector `before` to sector `after`. A sector is a
  contiguous x, y sub-region of world. Sectors are used to speed up
  world rendering.
  """
  before_set = set()
  after_set = set()
  pad = 4
  for dx in xrange(-pad, pad + 1):
for dy in [0]:  # xrange(-pad, pad + 1):
 for dz in xrange(-pad, pad + 1):
  if dx ** 2 + dy ** 2 + dz ** 2 > (pad + 1) ** 2:continue
  if before:x, y, z = beforebefore_set.add((x + dx, y + dy, z + dz))
  if after:x, y, z = afterafter_set.add((x + dx, y + dy, z + dz))
  show = after_set - before_set
  hide = before_set - after_set
  for sector in show:
self.show_sector(sector)
  for sector in hide:
self.hide_sector(sector)
 
 def _enqueue(self, func, *args):
  """ Add `func` to the internal queue.
  """
  self.queue.append((func, args))
 
 def _dequeue(self):
  """ Pop the top function from the internal queue and call it.
  """
  func, args = self.queue.popleft()
  func(*args)
 
 def process_queue(self):
  """ Process the entire queue while taking periodic breaks. This allows
  the game loop to run smoothly. The queue contains calls to
  _show_block() and _hide_block() so this method should be called if
  add_block() or remove_block() was called with immediate=False
  """
  start = time.clock()
  while self.queue and time.clock() - start < 1.0 / TICKS_PER_SEC:
self._dequeue()
 
 def process_entire_queue(self):
  """ Process the entire queue with no breaks.
  """
  while self.queue:
self._dequeue()
 
 
class Window(pyglet.window.Window):
 
 def __init__(self, *args, **kwargs):
  super(Window, self).__init__(*args, **kwargs)
 
  # Whether or not the window exclusively captures the mouse.
  self.exclusive = False
 
  # When flying gravity has no effect and speed is increased.
  self.flying = False
 
  # Strafing is moving lateral to the direction you are facing,
  # e.g. moving to the left or right while continuing to face forward.
  #
  # First element is -1 when moving forward, 1 when moving back, and 0
  # otherwise. The second element is -1 when moving left, 1 when moving
  # right, and 0 otherwise.
  self.strafe = [0, 0]
 
  # Current (x, y, z) position in the world, specified with floats. Note
  # that, perhaps unlike in math class, the y-axis is the vertical axis.
  self.position = (0, 0, 0)
 
  # First element is rotation of the player in the x-z plane (ground
  # plane) measured from the z-axis down. The second is the rotation
  # angle from the ground plane up. Rotation is in degrees.
  #
  # The vertical plane rotation ranges from -90 (looking straight down) to
  # 90 (looking straight up). The horizontal rotation range is unbounded.
  self.rotation = (0, 0)
 
  # Which sector the player is currently in.
  self.sector = None
 
  # The crosshairs at the center of the screen.
  self.reticle = None
 
  # Velocity in the y (upward) direction.
  self.dy = 0
 
  # A list of blocks the player can place. Hit num keys to cycle.
  self.inventory = [BRICK, GRASS, SAND]
 
  # The current block the user can place. Hit num keys to cycle.
  self.block = self.inventory[0]
 
  # Convenience list of num keys.
  self.num_keys = [
key._1, key._2, key._3, key._4, key._5,
key._6, key._7, key._8, key._9, key._0]
 
  # Instance of the model that handles the world.
  self.model = Model()
 
  # The label that is displayed in the top left of the canvas.
  self.label = pyglet.text.Label('', font_name='Arial', font_size=18,
x=10, y=self.height - 10, anchor_x='left', anchor_y='top',
color=(0, 0, 0, 255))
 
  # This call schedules the `update()` method to be called
  # TICKS_PER_SEC. This is the main game event loop.
  pyglet.clock.schedule_interval(self.update, 1.0 / TICKS_PER_SEC)
 
 def set_exclusive_mouse(self, exclusive):
  """ If `exclusive` is True, the game will capture the mouse, if False
  the game will ignore the mouse.
  """
  super(Window, self).set_exclusive_mouse(exclusive)
  self.exclusive = exclusive
 
 def get_sight_vector(self):
  """ Returns the current line of sight vector indicating the direction
  the player is looking.
  """
  x, y = self.rotation
  # y ranges from -90 to 90, or -pi/2 to pi/2, so m ranges from 0 to 1 and
  # is 1 when looking ahead parallel to the ground and 0 when looking
  # straight up or down.
  m = math.cos(math.radians(y))
  # dy ranges from -1 to 1 and is -1 when looking straight down and 1 when
  # looking straight up.
  dy = math.sin(math.radians(y))
  dx = math.cos(math.radians(x - 90)) * m
  dz = math.sin(math.radians(x - 90)) * m
  return (dx, dy, dz)
 
 def get_motion_vector(self):
  """ Returns the current motion vector indicating the velocity of the
  player.
  Returns
  -------
  vector : tuple of len 3
Tuple containing the velocity in x, y, and z respectively.
  """
  if any(self.strafe):
x, y = self.rotation
strafe = math.degrees(math.atan2(*self.strafe))
y_angle = math.radians(y)
x_angle = math.radians(x + strafe)
if self.flying:
 m = math.cos(y_angle)
 dy = math.sin(y_angle)
 if self.strafe[1]:
  # Moving left or right.
  dy = 0.0
  m = 1
 if self.strafe[0] > 0:
  # Moving backwards.
  dy *= -1
 # When you are flying up or down, you have less left and right
 # motion.
 dx = math.cos(x_angle) * m
 dz = math.sin(x_angle) * m
else:
 dy = 0.0
 dx = math.cos(x_angle)
 dz = math.sin(x_angle)
  else:
dy = 0.0
dx = 0.0
dz = 0.0
  return (dx, dy, dz)
 
 def update(self, dt):
  """ This method is scheduled to be called repeatedly by the pyglet
  clock.
  Parameters
  ----------
  dt : float
The change in time since the last call.
  """
  self.model.process_queue()
  sector = sectorize(self.position)
  if sector != self.sector:
self.model.change_sectors(self.sector, sector)
if self.sector is None:
 self.model.process_entire_queue()
self.sector = sector
  m = 8
  dt = min(dt, 0.2)
  for _ in xrange(m):
self._update(dt / m)
 
 def _update(self, dt):
  """ Private implementation of the `update()` method. This is where most
  of the motion logic lives, along with gravity and collision detection.
  Parameters
  ----------
  dt : float
The change in time since the last call.
  """
  # walking
  speed = FLYING_SPEED if self.flying else WALKING_SPEED
  d = dt * speed # distance covered this tick.
  dx, dy, dz = self.get_motion_vector()
  # New position in space, before accounting for gravity.
  dx, dy, dz = dx * d, dy * d, dz * d
  # gravity
  if not self.flying:
# Update your vertical speed: if you are falling, speed up until you
# hit terminal velocity; if you are jumping, slow down until you
# start falling.
self.dy -= dt * GRAVITY
self.dy = max(self.dy, -TERMINAL_VELOCITY)
dy += self.dy * dt
  # collisions
  x, y, z = self.position
  x, y, z = self.collide((x + dx, y + dy, z + dz), PLAYER_HEIGHT)
  self.position = (x, y, z)
 
 def collide(self, position, height):
  """ Checks to see if the player at the given `position` and `height`
  is colliding with any blocks in the world.
  Parameters
  ----------
  position : tuple of len 3
The (x, y, z) position to check for collisions at.
  height : int or float
The height of the player.
  Returns
  -------
  position : tuple of len 3
The new position of the player taking into account collisions.
  """
  # How much overlap with a dimension of a surrounding block you need to
  # have to count as a collision. If 0, touching terrain at all counts as
  # a collision. If .49, you sink into the ground, as if walking through
  # tall grass. If >= .5, you'll fall through the ground.
  pad = 0.25
  p = list(position)
  np = normalize(position)
  for face in FACES:  # check all surrounding blocks
for i in xrange(3):  # check each dimension independently
 if not face[i]:
  continue
 # How much overlap you have with this dimension.
 d = (p[i] - np[i]) * face[i]
 if d < pad:
  continue
 for dy in xrange(height):  # check each height
  op = list(np)
  op[1] -= dy
  op[i] += face[i]
  if tuple(op) not in self.model.world:continue
  p[i] -= (d - pad) * face[i]
  if face == (0, -1, 0) or face == (0, 1, 0):# You are colliding with the ground or ceiling, so stop# falling / rising.self.dy = 0
  break
  return tuple(p)
 
 def on_mouse_press(self, x, y, button, modifiers):
  """ Called when a mouse button is pressed. See pyglet docs for button
  amd modifier mappings.
  Parameters
  ----------
  x, y : int
The coordinates of the mouse click. Always center of the screen if
the mouse is captured.
  button : int
Number representing mouse button that was clicked. 1 = left button,
4 = right button.
  modifiers : int
Number representing any modifying keys that were pressed when the
mouse button was clicked.
  """
  if self.exclusive:
vector = self.get_sight_vector()
block, previous = self.model.hit_test(self.position, vector)
if (button == mouse.RIGHT) or \
  ((button == mouse.LEFT) and (modifiers & key.MOD_CTRL)):
 # ON OSX, control + left click = right click.
 if previous:
  self.model.add_block(previous, self.block)
elif button == pyglet.window.mouse.LEFT and block:
 texture = self.model.world[block]
 if texture != STONE:
  self.model.remove_block(block)
  else:
self.set_exclusive_mouse(True)
 
 def on_mouse_motion(self, x, y, dx, dy):
  """ Called when the player moves the mouse.
  Parameters
  ----------
  x, y : int
The coordinates of the mouse click. Always center of the screen if
the mouse is captured.
  dx, dy : float
The movement of the mouse.
  """
  if self.exclusive:
m = 0.15
x, y = self.rotation
x, y = x + dx * m, y + dy * m
y = max(-90, min(90, y))
self.rotation = (x, y)
 
 def on_key_press(self, symbol, modifiers):
  """ Called when the player presses a key. See pyglet docs for key
  mappings.
  Parameters
  ----------
  symbol : int
Number representing the key that was pressed.
  modifiers : int
Number representing any modifying keys that were pressed.
  """
  if symbol == key.W:
self.strafe[0] -= 1
  elif symbol == key.S:
self.strafe[0] += 1
  elif symbol == key.A:
self.strafe[1] -= 1
  elif symbol == key.D:
self.strafe[1] += 1
  elif symbol == key.SPACE:
if self.dy == 0:
 self.dy = JUMP_SPEED
  elif symbol == key.ESCAPE:
self.set_exclusive_mouse(False)
  elif symbol == key.TAB:
self.flying = not self.flying
  elif symbol in self.num_keys:
index = (symbol - self.num_keys[0]) % len(self.inventory)
self.block = self.inventory[index]
 
 def on_key_release(self, symbol, modifiers):
  """ Called when the player releases a key. See pyglet docs for key
  mappings.
  Parameters
  ----------
  symbol : int
Number representing the key that was pressed.
  modifiers : int
Number representing any modifying keys that were pressed.
  """
  if symbol == key.W:
self.strafe[0] += 1
  elif symbol == key.S:
self.strafe[0] -= 1
  elif symbol == key.A:
self.strafe[1] += 1
  elif symbol == key.D:
self.strafe[1] -= 1
 
 def on_resize(self, width, height):
  """ Called when the window is resized to a new `width` and `height`.
  """
  # label
  self.label.y = height - 10
  # reticle
  if self.reticle:
self.reticle.delete()
  x, y = self.width // 2, self.height // 2
  n = 10
  self.reticle = pyglet.graphics.vertex_list(4,
('v2i', (x - n, y, x + n, y, x, y - n, x, y + n))
  )
 
 def set_2d(self):
  """ Configure OpenGL to draw in 2d.
  """
  width, height = self.get_size()
  glDisable(GL_DEPTH_TEST)
  viewport = self.get_viewport_size()
  glViewport(0, 0, max(1, viewport[0]), max(1, viewport[1]))
  glMatrixMode(GL_PROJECTION)
  glLoadIdentity()
  glOrtho(0, max(1, width), 0, max(1, height), -1, 1)
  glMatrixMode(GL_MODELVIEW)
  glLoadIdentity()
 
 def set_3d(self):
  """ Configure OpenGL to draw in 3d.
  """
  width, height = self.get_size()
  glEnable(GL_DEPTH_TEST)
  viewport = self.get_viewport_size()
  glViewport(0, 0, max(1, viewport[0]), max(1, viewport[1]))
  glMatrixMode(GL_PROJECTION)
  glLoadIdentity()
  gluPerspective(65.0, width / float(height), 0.1, 60.0)
  glMatrixMode(GL_MODELVIEW)
  glLoadIdentity()
  x, y = self.rotation
  glRotatef(x, 0, 1, 0)
  glRotatef(-y, math.cos(math.radians(x)), 0, math.sin(math.radians(x)))
  x, y, z = self.position
  glTranslatef(-x, -y, -z)
 
 def on_draw(self):
  """ Called by pyglet to draw the canvas.
  """
  self.clear()
  self.set_3d()
  glColor3d(1, 1, 1)
  self.model.batch.draw()
  self.draw_focused_block()
  self.set_2d()
  self.draw_label()
  self.draw_reticle()
 
 def draw_focused_block(self):
  """ Draw black edges around the block that is currently under the
  crosshairs.
  """
  vector = self.get_sight_vector()
  block = self.model.hit_test(self.position, vector)[0]
  if block:
x, y, z = block
vertex_data = cube_vertices(x, y, z, 0.51)
glColor3d(0, 0, 0)
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE)
pyglet.graphics.draw(24, GL_QUADS, ('v3f/static', vertex_data))
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL)
 
 def draw_label(self):
  """ Draw the label in the top left of the screen.
  """
  x, y, z = self.position
  self.label.text = '%02d (%.2f, %.2f, %.2f) %d / %d' % (
pyglet.clock.get_fps(), x, y, z,
len(self.model._shown), len(self.model.world))
  self.label.draw()
 
 def draw_reticle(self):
  """ Draw the crosshairs in the center of the screen.
  """
  glColor3d(0, 0, 0)
  self.reticle.draw(GL_LINES)
 
 
def setup_fog():
 """ Configure the OpenGL fog properties.
 """
 # Enable fog. Fog "blends a fog color with each rasterized pixel fragment's
 # post-texturing color."
 glEnable(GL_FOG)
 # Set the fog color.
 glFogfv(GL_FOG_COLOR, (GLfloat * 4)(0.5, 0.69, 1.0, 1))
 # Say we have no preference between rendering speed and quality.
 glHint(GL_FOG_HINT, GL_DONT_CARE)
 # Specify the equation used to compute the blending factor.
 glFogi(GL_FOG_MODE, GL_LINEAR)
 # How close and far away fog starts and ends. The closer the start and end,
 # the denser the fog in the fog range.
 glFogf(GL_FOG_START, 20.0)
 glFogf(GL_FOG_END, 60.0)
 
 
def setup():
 """ Basic OpenGL configuration.
 """
 # Set the color of "clear", i.e. the sky, in rgba.
 glClearColor(0.5, 0.69, 1.0, 1)
 # Enable culling (not rendering) of back-facing facets -- facets that aren't
 # visible to you.
 glEnable(GL_CULL_FACE)
 # Set the texture minification/magnification function to GL_NEAREST (nearest
 # in Manhattan distance) to the specified texture coordinates. GL_NEAREST
 # "is generally faster than GL_LINEAR, but it can produce textured 圖片
 # with sharper edges because the transition between texture elements is not
 # as smooth."
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
 setup_fog()
 
 
def main():
 window = Window(width=1800, height=1600, caption='Pyglet', resizable=True)
 # Hide the mouse cursor and prevent the mouse from leaving the window.
 window.set_exclusive_mouse(True)
 setup()
 pyglet.app.run()
 
 
if __name__ == '__main__':
 main()