src/main/scala/li/cil/oc/common/tileentity/Screen.scala - minecraft/opencomputers - Rivoreo Source Code Repositories

 package li.cil.oc.common.tileentity

 import cpw.mods.fml.relauncher.{Side, SideOnly}
 import li.cil.oc.api.network._
 import li.cil.oc.client.renderer.MonospaceFontRenderer
 import li.cil.oc.client.{PacketSender => ClientPacketSender}
 import li.cil.oc.common.component
 import li.cil.oc.server.{PacketSender => ServerPacketSender}
 import li.cil.oc.Settings
 import li.cil.oc.util.Color
 import net.minecraft.client.Minecraft
 import net.minecraft.entity.Entity
 import net.minecraft.entity.player.EntityPlayer
 import net.minecraft.entity.projectile.EntityArrow
 import net.minecraft.nbt.NBTTagCompound
 import net.minecraft.util.AxisAlignedBB
 import net.minecraftforge.common.ForgeDirection
 import scala.collection.mutable
 import scala.language.postfixOps

 class Screen(var tier: Int) extends traits.TextBuffer with SidedEnvironment with traits.Rotatable with traits.RedstoneAware with traits.Colored with Analyzable with Ordered[Screen] {
   def this() = this(0)

   color = Color.byTier(tier)

   _isOutputEnabled = true

   override def validFacings = ForgeDirection.VALID_DIRECTIONS

   // ----------------------------------------------------------------------- //

   override protected val _buffer = new component.Buffer(this) {
     @Callback(doc = """function():boolean -- Returns whether the screen is currently on.""")
     def isOn(computer: Context, args: Arguments): Array[AnyRef] = result(origin.isOn)

     @Callback(doc = """function():boolean -- Turns the screen on. Returns true if it was off.""")
     def turnOn(computer: Context, args: Arguments): Array[AnyRef] = {
       if (!origin.isOn) {
         origin.turnOn()
         result(true, origin.isOn)
       }
       else result(false, origin.isOn)
     }

     @Callback(doc = """function():boolean -- Turns off the screen. Returns true if it was on.""")
     def turnOff(computer: Context, args: Arguments): Array[AnyRef] = {
       if (origin.isOn) {
         origin.turnOff()
         result(true, origin.isOn)
       }
       else result(false, origin.isOn)
     }
   }

   // This is the energy cost (per tick) to keep the screen running if every
   // single "pixel" is lit. This cost increases with higher tiers as their
   // maximum resolution (pixel density) increases. For a basic screen this is
   // simply the configured cost.
   val fullyLitCost = {
     val (w, h) = Settings.screenResolutionsByTier(0)
     val (mw, mh) = buffer.maxResolution
     Settings.get.screenCost * (mw * mh) / (w * h)
   }

   /**
    * Check for multi-block screen option in next update. We do this in the
    * update to avoid unnecessary checks on chunk unload.
    */
   var shouldCheckForMultiBlock = true

   var width, height = 1

   var origin = this

   val screens = mutable.Set(this)

   var relativeLitArea = -1.0

   var hasPower = true

   var isOn = true

   var hadRedstoneInput = false

   var cachedBounds: Option[AxisAlignedBB] = None

   private val arrows = mutable.Set.empty[EntityArrow]

   @SideOnly(Side.CLIENT)
   override def canConnect(side: ForgeDirection) = toLocal(side) != ForgeDirection.SOUTH

   // Allow connections from front for keyboards, just don't render cables as connected...
   override def sidedNode(side: ForgeDirection) = node

   // ----------------------------------------------------------------------- //

   def isOrigin = origin == this

   def localPosition = {
     val (lx, ly, _) = project(this)
     val (ox, oy, _) = project(origin)
     (lx - ox, ly - oy)
   }

   override def hasKeyboard = screens.exists(screen =>
     ForgeDirection.VALID_DIRECTIONS.map(side => (side, world.getBlockTileEntity(screen.x + side.offsetX, screen.y + side.offsetY, screen.z + side.offsetZ))).exists {
       case (side, keyboard: Keyboard) => keyboard.hasNodeOnSide(side.getOpposite)
       case _ => false
     })

   def checkMultiBlock() {
     shouldCheckForMultiBlock = true
     width = 1
     height = 1
     origin = this
     screens.clear()
     screens += this
     cachedBounds = None
   }

   def click(player: EntityPlayer, hitX: Double, hitY: Double, hitZ: Double): Boolean = {
     // Compute absolute position of the click on the face, measured in blocks.
     def dot(f: ForgeDirection) = f.offsetX * hitX + f.offsetY * hitY + f.offsetZ * hitZ
     val (hx, hy) = (dot(toGlobal(ForgeDirection.EAST)), dot(toGlobal(ForgeDirection.UP)))
     val tx = if (hx < 0) 1 + hx else hx
     val ty = 1 - (if (hy < 0) 1 + hy else hy)
     val (lx, ly) = localPosition
     val (ax, ay) = (lx + tx, height - 1 - ly + ty)

     // Get the relative position in the *display area* of the face.
     val border = 2.25 / 16.0
     if (ax <= border || ay <= border || ax >= width - border || ay >= height - border) {
       return false
     }
     val (iw, ih) = (width - border * 2, height - border * 2)
     val (rx, ry) = ((ax - border) / iw, (ay - border) / ih)

     // Make it a relative position in the displayed buffer.
     val (bw, bh) = origin.buffer.resolution
     val (bpw, bph) = (bw * MonospaceFontRenderer.fontWidth / iw.toDouble, bh * MonospaceFontRenderer.fontHeight / ih.toDouble)
     val (brx, bry) = if (bpw > bph) {
       val rh = bph.toDouble / bpw.toDouble
       val bry = (ry - (1 - rh) * 0.5) / rh
       if (bry <= 0 || bry >= 1) {
         return false
       }
       (rx, bry)
     }
     else if (bph > bpw) {
       val rw = bpw.toDouble / bph.toDouble
       val brx = (rx - (1 - rw) * 0.5) / rw
       if (brx <= 0 || brx >= 1) {
         return false
       }
       (brx, ry)
     }
     else {
       (rx, ry)
     }

     // Convert to absolute coordinates and send the packet to the server.
     if (world.isRemote) {
       ClientPacketSender.sendMouseClick(this.buffer, (brx * bw).toInt + 1, (bry * bh).toInt + 1, drag = false, 0)
     }
     true
   }

   def walk(entity: Entity) {
     val (x, y) = localPosition
     entity match {
       case player: EntityPlayer if Settings.get.inputUsername =>
         origin.node.sendToReachable("computer.signal", "walk", Int.box(x + 1), Int.box(height - y), player.getCommandSenderName)
       case _ =>
         origin.node.sendToReachable("computer.signal", "walk", Int.box(x + 1), Int.box(height - y))
     }
   }

   def shot(arrow: EntityArrow, hitX: Double, hitY: Double, hitZ: Double) {
     // This is nasty, but I see no other way: arrows can trigger two collisions,
     // once on their own when hitting a block, a second time via their entity's
     // common collision checker. The second one (collision checker) has the
     // better coordinates (arrow moved back out of the block it collided with),
     // so use that when possible, otherwise resolve in next update.
     if (!arrows.add(arrow)) {
       arrows.remove(arrow)
       arrow.shootingEntity match {
         case player: EntityPlayer => click(player, hitX, hitY, hitZ)
         case _ =>
       }
     }
   }

   def turnOn() {
     origin.isOn = true
     val neededPower = width * height * Settings.get.screenCost * Settings.get.tickFrequency
     origin.hasPower = buffer.node.changeBuffer(-neededPower) == 0
     ServerPacketSender.sendScreenPowerChange(origin, origin.isOn && origin.hasPower)
   }

   def turnOff() {
     origin.isOn = false
     ServerPacketSender.sendScreenPowerChange(origin, origin.isOn && origin.hasPower)
   }

   // ----------------------------------------------------------------------- //

   override def updateEntity() {
     super.updateEntity()
     if (isServer && isOn && isOrigin && world.getWorldTime % Settings.get.tickFrequency == 0) {
       if (relativeLitArea < 0) {
         // The relative lit area is the number of pixels that are not blank
         // versus the number of pixels in the *current* resolution. This is
         // scaled to multi-block screens, since we only compute this for the
         // origin.
         val (w, h) = buffer.resolution
         relativeLitArea = width * height * buffer.lines.foldLeft(0) {
           (acc, line) => acc + line.count(' ' !=)
         } / (w * h).toDouble
       }
       val hadPower = hasPower
       val neededPower = relativeLitArea * fullyLitCost * Settings.get.tickFrequency
       hasPower = buffer.node.tryChangeBuffer(-neededPower)
       if (hasPower != hadPower) {
         ServerPacketSender.sendScreenPowerChange(this, isOn && hasPower)
       }
     }
     if (shouldCheckForMultiBlock) {
       // Make sure we merge in a deterministic order, to avoid getting
       // different results on server and client due to the update order
       // differing between the two. This also saves us from having to save
       // any multi-block specific state information.
       val pending = mutable.SortedSet(this)
       val queue = mutable.Queue(this)
       while (queue.nonEmpty) {
         val current = queue.dequeue()
         val (lx, ly, lz) = project(current)
         def tryQueue(dx: Int, dy: Int) {
           val (nx, ny, nz) = unproject(lx + dx, ly + dy, lz)
           world.getBlockTileEntity(nx, ny, nz) match {
             case s: Screen if s.pitch == pitch && s.yaw == yaw && pending.add(s) => queue += s
             case _ => // Ignore.
           }
         }
         tryQueue(-1, 0)
         tryQueue(1, 0)
         tryQueue(0, -1)
         tryQueue(0, 1)
       }
       // Perform actual merges.
       while (pending.nonEmpty) {
         val current = pending.firstKey
         while (current.tryMerge()) {}
         current.screens.foreach {
           screen =>
             screen.shouldCheckForMultiBlock = false
             screen.bufferIsDirty = true
             pending.remove(screen)
             queue += screen
         }
         if (isClient) {
           val bounds = current.origin.getRenderBoundingBox
           world.markBlockRangeForRenderUpdate(bounds.minX.toInt, bounds.minY.toInt, bounds.minZ.toInt,
             bounds.maxX.toInt, bounds.maxY.toInt, bounds.maxZ.toInt)
         }
       }
       // Update visibility after everything is done, to avoid noise.
       queue.foreach(screen =>
         if (screen.isOrigin) {
           if (isServer) {
             screen.buffer.node.setVisibility(Visibility.Network)
           }
         }
         else {
           if (isServer) {
             screen.buffer.node.setVisibility(Visibility.None)
           }
           val buffer = screen.buffer
           val (w, h) = buffer.resolution
           buffer.foreground = 0xFFFFFF
           buffer.background = 0x000000
           if (buffer.buffer.fill(0, 0, w, h, ' ')) {
             onScreenFill(0, 0, w, h, ' ')
           }
         }
       )
     }
     if (arrows.size > 0) {
       for (arrow <- arrows) {
         val hitX = math.max(0, math.min(1, arrow.posX - x))
         val hitY = math.max(0, math.min(1, arrow.posY - y))
         val hitZ = math.max(0, math.min(1, arrow.posZ - z))
         shot(arrow, hitX, hitY, hitZ)
       }
       assert(arrows.isEmpty)
     }
   }

   override def onChunkUnload() {
     super.onChunkUnload()
     cleanup()
   }

   override def invalidate() {
     super.invalidate()
     cleanup()
   }

   protected def cleanup() {
     if (currentGui.isDefined) {
       Minecraft.getMinecraft.displayGuiScreen(null)
     }
     screens.clone().foreach(_.checkMultiBlock())
   }

   // ----------------------------------------------------------------------- //

   override def readFromNBT(nbt: NBTTagCompound) {
     tier = nbt.getByte(Settings.namespace + "tier") max 0 min 2
     color = Color.byTier(tier)
     super.readFromNBT(nbt)
     // This check is just to avoid powering off any screens that have been
     // placed before this was introduced.
     if (nbt.hasKey(Settings.namespace + "isOn")) {
       isOn = nbt.getBoolean(Settings.namespace + "isOn")
     }
     if (nbt.hasKey(Settings.namespace + "isOn")) {
       hasPower = nbt.getBoolean(Settings.namespace + "hasPower")
     }
     hadRedstoneInput = nbt.getBoolean(Settings.namespace + "hadRedstoneInput")
   }

   override def writeToNBT(nbt: NBTTagCompound) {
     nbt.setByte(Settings.namespace + "tier", tier.toByte)
     super.writeToNBT(nbt)
     nbt.setBoolean(Settings.namespace + "isOn", isOn)
     nbt.setBoolean(Settings.namespace + "hasPower", hasPower)
     nbt.setBoolean(Settings.namespace + "hadRedstoneInput", hadRedstoneInput)
   }

   @SideOnly(Side.CLIENT)
   override def readFromNBTForClient(nbt: NBTTagCompound) {
     super.readFromNBTForClient(nbt)
     hasPower = nbt.getBoolean("hasPower")
   }

   override def writeToNBTForClient(nbt: NBTTagCompound) {
     super.writeToNBTForClient(nbt)
     nbt.setBoolean("hasPower", isOn && hasPower)
   }

   // ----------------------------------------------------------------------- //

   @SideOnly(Side.CLIENT)
   override def getRenderBoundingBox =
     if ((width == 1 && height == 1) || !isOrigin) super.getRenderBoundingBox
     else cachedBounds match {
       case Some(bounds) => bounds
       case _ =>
         val (sx, sy, sz) = unproject(width, height, 1)
         val ox = x + (if (sx < 0) 1 else 0)
         val oy = y + (if (sy < 0) 1 else 0)
         val oz = z + (if (sz < 0) 1 else 0)
         val b = AxisAlignedBB.getBoundingBox(ox, oy, oz, ox + sx, oy + sy, oz + sz)
         b.setBounds(math.min(b.minX, b.maxX), math.min(b.minY, b.maxY), math.min(b.minZ, b.maxZ),
           math.max(b.minX, b.maxX), math.max(b.minY, b.maxY), math.max(b.minZ, b.maxZ))
         cachedBounds = Some(b)
         b
     }

   @SideOnly(Side.CLIENT)
   override def getMaxRenderDistanceSquared = if (isOrigin) super.getMaxRenderDistanceSquared else 0

   // ----------------------------------------------------------------------- //

   override def onAnalyze(player: EntityPlayer, side: Int, hitX: Float, hitY: Float, hitZ: Float) = Array(origin.node)

   override protected def onRedstoneInputChanged(side: ForgeDirection) {
     super.onRedstoneInputChanged(side)
     val hasRedstoneInput = screens.map(_.maxInput).max > 0
     if (hasRedstoneInput != hadRedstoneInput) {
       hadRedstoneInput = hasRedstoneInput
       if (hasRedstoneInput) {
         if (origin.isOn) turnOff() else turnOn()
       }
     }
   }

   override def onRotationChanged() {
     super.onRotationChanged()
     screens.clone().foreach(_.checkMultiBlock())
   }

   override def onScreenCopy(col: Int, row: Int, w: Int, h: Int, tx: Int, ty: Int) {
     super.onScreenCopy(col, row, w, h, tx, ty)
     relativeLitArea = -1
   }

   override def onScreenFill(col: Int, row: Int, w: Int, h: Int, c: Char) {
     super.onScreenFill(col, row, w, h, c)
     relativeLitArea = -1
   }

   override def onScreenResolutionChange(w: Int, h: Int) {
     super.onScreenResolutionChange(w, h)
     relativeLitArea = -1
   }

   override def onScreenSet(col: Int, row: Int, s: String) {
     super.onScreenSet(col, row, s)
     relativeLitArea = -1
   }

   @SideOnly(Side.CLIENT)
   override protected def markForRenderUpdate() {
     super.markForRenderUpdate()
     currentGui.foreach(_.recompileDisplayLists())
   }

   // ----------------------------------------------------------------------- //

   override def compare(that: Screen) =
     if (x != that.x) x - that.x
     else if (y != that.y) y - that.y
     else z - that.z

   // ----------------------------------------------------------------------- //

   private def tryMerge() = {
     val (ox, oy, oz) = project(origin)
     def tryMergeTowards(dx: Int, dy: Int) = {
       val (nx, ny, nz) = unproject(ox + dx, oy + dy, oz)
       world.getBlockTileEntity(nx, ny, nz) match {
         case s: Screen if s.tier == tier && s.pitch == pitch && s.yaw == yaw && !screens.contains(s) =>
           val (sx, sy, _) = project(s.origin)
           val canMergeAlongX = sy == oy && s.height == height && s.width + width <= Settings.get.maxScreenWidth
           val canMergeAlongY = sx == ox && s.width == width && s.height + height <= Settings.get.maxScreenHeight
           if (canMergeAlongX || canMergeAlongY) {
             val (newOrigin) =
               if (canMergeAlongX) {
                 if (sx < ox) s.origin else origin
               }
               else {
                 if (sy < oy) s.origin else origin
               }
             val (newWidth, newHeight) =
               if (canMergeAlongX) (width + s.width, height)
               else (width, height + s.height)
             val newScreens = screens ++ s.screens
             for (screen <- newScreens) {
               screen.width = newWidth
               screen.height = newHeight
               screen.origin = newOrigin
               screen.screens ++= newScreens // It's a set, so there won't be duplicates.
               screen.cachedBounds = None
             }
             true
           }
           else false // Cannot merge.
         case _ => false
       }
     }
     tryMergeTowards(0, height) || tryMergeTowards(0, -1) || tryMergeTowards(width, 0) || tryMergeTowards(-1, 0)
   }

   private def project(t: Screen) = {
     def dot(f: ForgeDirection, s: Screen) = f.offsetX * s.x + f.offsetY * s.y + f.offsetZ * s.z
     (dot(toGlobal(ForgeDirection.EAST), t), dot(toGlobal(ForgeDirection.UP), t), dot(toGlobal(ForgeDirection.SOUTH), t))
   }

   private def unproject(x: Int, y: Int, z: Int) = {
     def dot(f: ForgeDirection) = f.offsetX * x + f.offsetY * y + f.offsetZ * z
     (dot(toLocal(ForgeDirection.EAST)), dot(toLocal(ForgeDirection.UP)), dot(toLocal(ForgeDirection.SOUTH)))
   }
 }
	package li.cil.oc.common.tileentity

	import cpw.mods.fml.relauncher.{Side, SideOnly}
	import li.cil.oc.api.network._
	import li.cil.oc.client.renderer.MonospaceFontRenderer
	import li.cil.oc.client.{PacketSender => ClientPacketSender}
	import li.cil.oc.common.component
	import li.cil.oc.server.{PacketSender => ServerPacketSender}
	import li.cil.oc.Settings
	import li.cil.oc.util.Color
	import net.minecraft.client.Minecraft
	import net.minecraft.entity.Entity
	import net.minecraft.entity.player.EntityPlayer
	import net.minecraft.entity.projectile.EntityArrow
	import net.minecraft.nbt.NBTTagCompound
	import net.minecraft.util.AxisAlignedBB
	import net.minecraftforge.common.ForgeDirection
	import scala.collection.mutable
	import scala.language.postfixOps

	class Screen(var tier: Int) extends traits.TextBuffer with SidedEnvironment with traits.Rotatable with traits.RedstoneAware with traits.Colored with Analyzable with Ordered[Screen] {
	def this() = this(0)

	color = Color.byTier(tier)

	_isOutputEnabled = true

	override def validFacings = ForgeDirection.VALID_DIRECTIONS

	// ----------------------------------------------------------------------- //

	override protected val _buffer = new component.Buffer(this) {
	@Callback(doc = """function():boolean -- Returns whether the screen is currently on.""")
	def isOn(computer: Context, args: Arguments): Array[AnyRef] = result(origin.isOn)

	@Callback(doc = """function():boolean -- Turns the screen on. Returns true if it was off.""")
	def turnOn(computer: Context, args: Arguments): Array[AnyRef] = {
	if (!origin.isOn) {
	origin.turnOn()
	result(true, origin.isOn)
	}
	else result(false, origin.isOn)
	}

	@Callback(doc = """function():boolean -- Turns off the screen. Returns true if it was on.""")
	def turnOff(computer: Context, args: Arguments): Array[AnyRef] = {
	if (origin.isOn) {
	origin.turnOff()
	result(true, origin.isOn)
	}
	else result(false, origin.isOn)
	}
	}

	// This is the energy cost (per tick) to keep the screen running if every
	// single "pixel" is lit. This cost increases with higher tiers as their
	// maximum resolution (pixel density) increases. For a basic screen this is
	// simply the configured cost.
	val fullyLitCost = {
	val (w, h) = Settings.screenResolutionsByTier(0)
	val (mw, mh) = buffer.maxResolution
	Settings.get.screenCost * (mw * mh) / (w * h)
	}

	/**
	* Check for multi-block screen option in next update. We do this in the
	* update to avoid unnecessary checks on chunk unload.
	*/
	var shouldCheckForMultiBlock = true

	var width, height = 1

	var origin = this

	val screens = mutable.Set(this)

	var relativeLitArea = -1.0

	var hasPower = true

	var isOn = true

	var hadRedstoneInput = false

	var cachedBounds: Option[AxisAlignedBB] = None

	private val arrows = mutable.Set.empty[EntityArrow]

	@SideOnly(Side.CLIENT)
	override def canConnect(side: ForgeDirection) = toLocal(side) != ForgeDirection.SOUTH

	// Allow connections from front for keyboards, just don't render cables as connected...
	override def sidedNode(side: ForgeDirection) = node

	// ----------------------------------------------------------------------- //

	def isOrigin = origin == this

	def localPosition = {
	val (lx, ly, _) = project(this)
	val (ox, oy, _) = project(origin)
	(lx - ox, ly - oy)
	}

	override def hasKeyboard = screens.exists(screen =>
	ForgeDirection.VALID_DIRECTIONS.map(side => (side, world.getBlockTileEntity(screen.x + side.offsetX, screen.y + side.offsetY, screen.z + side.offsetZ))).exists {
	case (side, keyboard: Keyboard) => keyboard.hasNodeOnSide(side.getOpposite)
	case _ => false
	})

	def checkMultiBlock() {
	shouldCheckForMultiBlock = true
	width = 1
	height = 1
	origin = this
	screens.clear()
	screens += this
	cachedBounds = None
	}

	def click(player: EntityPlayer, hitX: Double, hitY: Double, hitZ: Double): Boolean = {
	// Compute absolute position of the click on the face, measured in blocks.
	def dot(f: ForgeDirection) = f.offsetX * hitX + f.offsetY * hitY + f.offsetZ * hitZ
	val (hx, hy) = (dot(toGlobal(ForgeDirection.EAST)), dot(toGlobal(ForgeDirection.UP)))
	val tx = if (hx < 0) 1 + hx else hx
	val ty = 1 - (if (hy < 0) 1 + hy else hy)
	val (lx, ly) = localPosition
	val (ax, ay) = (lx + tx, height - 1 - ly + ty)

	// Get the relative position in the display area of the face.
	val border = 2.25 / 16.0
	if (ax <= border \|\| ay <= border \|\| ax >= width - border \|\| ay >= height - border) {
	return false
	}
	val (iw, ih) = (width - border * 2, height - border * 2)
	val (rx, ry) = ((ax - border) / iw, (ay - border) / ih)

	// Make it a relative position in the displayed buffer.
	val (bw, bh) = origin.buffer.resolution
	val (bpw, bph) = (bw * MonospaceFontRenderer.fontWidth / iw.toDouble, bh * MonospaceFontRenderer.fontHeight / ih.toDouble)
	val (brx, bry) = if (bpw > bph) {
	val rh = bph.toDouble / bpw.toDouble
	val bry = (ry - (1 - rh) * 0.5) / rh
	if (bry <= 0 \|\| bry >= 1) {
	return false
	}
	(rx, bry)
	}
	else if (bph > bpw) {
	val rw = bpw.toDouble / bph.toDouble
	val brx = (rx - (1 - rw) * 0.5) / rw
	if (brx <= 0 \|\| brx >= 1) {
	return false
	}
	(brx, ry)
	}
	else {
	(rx, ry)
	}

	// Convert to absolute coordinates and send the packet to the server.
	if (world.isRemote) {
	ClientPacketSender.sendMouseClick(this.buffer, (brx * bw).toInt + 1, (bry * bh).toInt + 1, drag = false, 0)
	}
	true
	}

	def walk(entity: Entity) {
	val (x, y) = localPosition
	entity match {
	case player: EntityPlayer if Settings.get.inputUsername =>
	origin.node.sendToReachable("computer.signal", "walk", Int.box(x + 1), Int.box(height - y), player.getCommandSenderName)
	case _ =>
	origin.node.sendToReachable("computer.signal", "walk", Int.box(x + 1), Int.box(height - y))
	}
	}

	def shot(arrow: EntityArrow, hitX: Double, hitY: Double, hitZ: Double) {
	// This is nasty, but I see no other way: arrows can trigger two collisions,
	// once on their own when hitting a block, a second time via their entity's
	// common collision checker. The second one (collision checker) has the
	// better coordinates (arrow moved back out of the block it collided with),
	// so use that when possible, otherwise resolve in next update.
	if (!arrows.add(arrow)) {
	arrows.remove(arrow)
	arrow.shootingEntity match {
	case player: EntityPlayer => click(player, hitX, hitY, hitZ)
	case _ =>
	}
	}
	}

	def turnOn() {
	origin.isOn = true
	val neededPower = width * height * Settings.get.screenCost * Settings.get.tickFrequency
	origin.hasPower = buffer.node.changeBuffer(-neededPower) == 0
	ServerPacketSender.sendScreenPowerChange(origin, origin.isOn && origin.hasPower)
	}

	def turnOff() {
	origin.isOn = false
	ServerPacketSender.sendScreenPowerChange(origin, origin.isOn && origin.hasPower)
	}

	// ----------------------------------------------------------------------- //

	override def updateEntity() {
	super.updateEntity()
	if (isServer && isOn && isOrigin && world.getWorldTime % Settings.get.tickFrequency == 0) {
	if (relativeLitArea < 0) {
	// The relative lit area is the number of pixels that are not blank
	// versus the number of pixels in the current resolution. This is
	// scaled to multi-block screens, since we only compute this for the
	// origin.
	val (w, h) = buffer.resolution
	relativeLitArea = width * height * buffer.lines.foldLeft(0) {
	(acc, line) => acc + line.count(' ' !=)
	} / (w * h).toDouble
	}
	val hadPower = hasPower
	val neededPower = relativeLitArea * fullyLitCost * Settings.get.tickFrequency
	hasPower = buffer.node.tryChangeBuffer(-neededPower)
	if (hasPower != hadPower) {
	ServerPacketSender.sendScreenPowerChange(this, isOn && hasPower)
	}
	}
	if (shouldCheckForMultiBlock) {
	// Make sure we merge in a deterministic order, to avoid getting
	// different results on server and client due to the update order
	// differing between the two. This also saves us from having to save
	// any multi-block specific state information.
	val pending = mutable.SortedSet(this)
	val queue = mutable.Queue(this)
	while (queue.nonEmpty) {
	val current = queue.dequeue()
	val (lx, ly, lz) = project(current)
	def tryQueue(dx: Int, dy: Int) {
	val (nx, ny, nz) = unproject(lx + dx, ly + dy, lz)
	world.getBlockTileEntity(nx, ny, nz) match {
	case s: Screen if s.pitch == pitch && s.yaw == yaw && pending.add(s) => queue += s
	case _ => // Ignore.
	}
	}
	tryQueue(-1, 0)
	tryQueue(1, 0)
	tryQueue(0, -1)
	tryQueue(0, 1)
	}
	// Perform actual merges.
	while (pending.nonEmpty) {
	val current = pending.firstKey
	while (current.tryMerge()) {}
	current.screens.foreach {
	screen =>
	screen.shouldCheckForMultiBlock = false
	screen.bufferIsDirty = true
	pending.remove(screen)
	queue += screen
	}
	if (isClient) {
	val bounds = current.origin.getRenderBoundingBox
	world.markBlockRangeForRenderUpdate(bounds.minX.toInt, bounds.minY.toInt, bounds.minZ.toInt,
	bounds.maxX.toInt, bounds.maxY.toInt, bounds.maxZ.toInt)
	}
	}
	// Update visibility after everything is done, to avoid noise.
	queue.foreach(screen =>
	if (screen.isOrigin) {
	if (isServer) {
	screen.buffer.node.setVisibility(Visibility.Network)
	}
	}
	else {
	if (isServer) {
	screen.buffer.node.setVisibility(Visibility.None)
	}
	val buffer = screen.buffer
	val (w, h) = buffer.resolution
	buffer.foreground = 0xFFFFFF
	buffer.background = 0x000000
	if (buffer.buffer.fill(0, 0, w, h, ' ')) {
	onScreenFill(0, 0, w, h, ' ')
	}
	}
	)
	}
	if (arrows.size > 0) {
	for (arrow <- arrows) {
	val hitX = math.max(0, math.min(1, arrow.posX - x))
	val hitY = math.max(0, math.min(1, arrow.posY - y))
	val hitZ = math.max(0, math.min(1, arrow.posZ - z))
	shot(arrow, hitX, hitY, hitZ)
	}
	assert(arrows.isEmpty)
	}
	}

	override def onChunkUnload() {
	super.onChunkUnload()
	cleanup()
	}

	override def invalidate() {
	super.invalidate()
	cleanup()
	}

	protected def cleanup() {
	if (currentGui.isDefined) {
	Minecraft.getMinecraft.displayGuiScreen(null)
	}
	screens.clone().foreach(_.checkMultiBlock())
	}

	// ----------------------------------------------------------------------- //

	override def readFromNBT(nbt: NBTTagCompound) {
	tier = nbt.getByte(Settings.namespace + "tier") max 0 min 2
	color = Color.byTier(tier)
	super.readFromNBT(nbt)
	// This check is just to avoid powering off any screens that have been
	// placed before this was introduced.
	if (nbt.hasKey(Settings.namespace + "isOn")) {
	isOn = nbt.getBoolean(Settings.namespace + "isOn")
	}
	if (nbt.hasKey(Settings.namespace + "isOn")) {
	hasPower = nbt.getBoolean(Settings.namespace + "hasPower")
	}
	hadRedstoneInput = nbt.getBoolean(Settings.namespace + "hadRedstoneInput")
	}

	override def writeToNBT(nbt: NBTTagCompound) {
	nbt.setByte(Settings.namespace + "tier", tier.toByte)
	super.writeToNBT(nbt)
	nbt.setBoolean(Settings.namespace + "isOn", isOn)
	nbt.setBoolean(Settings.namespace + "hasPower", hasPower)
	nbt.setBoolean(Settings.namespace + "hadRedstoneInput", hadRedstoneInput)
	}

	@SideOnly(Side.CLIENT)
	override def readFromNBTForClient(nbt: NBTTagCompound) {
	super.readFromNBTForClient(nbt)
	hasPower = nbt.getBoolean("hasPower")
	}

	override def writeToNBTForClient(nbt: NBTTagCompound) {
	super.writeToNBTForClient(nbt)
	nbt.setBoolean("hasPower", isOn && hasPower)
	}

	// ----------------------------------------------------------------------- //

	@SideOnly(Side.CLIENT)
	override def getRenderBoundingBox =
	if ((width == 1 && height == 1) \|\| !isOrigin) super.getRenderBoundingBox
	else cachedBounds match {
	case Some(bounds) => bounds
	case _ =>
	val (sx, sy, sz) = unproject(width, height, 1)
	val ox = x + (if (sx < 0) 1 else 0)
	val oy = y + (if (sy < 0) 1 else 0)
	val oz = z + (if (sz < 0) 1 else 0)
	val b = AxisAlignedBB.getBoundingBox(ox, oy, oz, ox + sx, oy + sy, oz + sz)
	b.setBounds(math.min(b.minX, b.maxX), math.min(b.minY, b.maxY), math.min(b.minZ, b.maxZ),
	math.max(b.minX, b.maxX), math.max(b.minY, b.maxY), math.max(b.minZ, b.maxZ))
	cachedBounds = Some(b)
	b
	}

	@SideOnly(Side.CLIENT)
	override def getMaxRenderDistanceSquared = if (isOrigin) super.getMaxRenderDistanceSquared else 0

	// ----------------------------------------------------------------------- //

	override def onAnalyze(player: EntityPlayer, side: Int, hitX: Float, hitY: Float, hitZ: Float) = Array(origin.node)

	override protected def onRedstoneInputChanged(side: ForgeDirection) {
	super.onRedstoneInputChanged(side)
	val hasRedstoneInput = screens.map(_.maxInput).max > 0
	if (hasRedstoneInput != hadRedstoneInput) {
	hadRedstoneInput = hasRedstoneInput
	if (hasRedstoneInput) {
	if (origin.isOn) turnOff() else turnOn()
	}
	}
	}

	override def onRotationChanged() {
	super.onRotationChanged()
	screens.clone().foreach(_.checkMultiBlock())
	}

	override def onScreenCopy(col: Int, row: Int, w: Int, h: Int, tx: Int, ty: Int) {
	super.onScreenCopy(col, row, w, h, tx, ty)
	relativeLitArea = -1
	}

	override def onScreenFill(col: Int, row: Int, w: Int, h: Int, c: Char) {
	super.onScreenFill(col, row, w, h, c)
	relativeLitArea = -1
	}

	override def onScreenResolutionChange(w: Int, h: Int) {
	super.onScreenResolutionChange(w, h)
	relativeLitArea = -1
	}

	override def onScreenSet(col: Int, row: Int, s: String) {
	super.onScreenSet(col, row, s)
	relativeLitArea = -1
	}

	@SideOnly(Side.CLIENT)
	override protected def markForRenderUpdate() {
	super.markForRenderUpdate()
	currentGui.foreach(_.recompileDisplayLists())
	}

	// ----------------------------------------------------------------------- //

	override def compare(that: Screen) =
	if (x != that.x) x - that.x
	else if (y != that.y) y - that.y
	else z - that.z

	// ----------------------------------------------------------------------- //

	private def tryMerge() = {
	val (ox, oy, oz) = project(origin)
	def tryMergeTowards(dx: Int, dy: Int) = {
	val (nx, ny, nz) = unproject(ox + dx, oy + dy, oz)
	world.getBlockTileEntity(nx, ny, nz) match {
	case s: Screen if s.tier == tier && s.pitch == pitch && s.yaw == yaw && !screens.contains(s) =>
	val (sx, sy, _) = project(s.origin)
	val canMergeAlongX = sy == oy && s.height == height && s.width + width <= Settings.get.maxScreenWidth
	val canMergeAlongY = sx == ox && s.width == width && s.height + height <= Settings.get.maxScreenHeight
	if (canMergeAlongX \|\| canMergeAlongY) {
	val (newOrigin) =
	if (canMergeAlongX) {
	if (sx < ox) s.origin else origin
	}
	else {
	if (sy < oy) s.origin else origin
	}
	val (newWidth, newHeight) =
	if (canMergeAlongX) (width + s.width, height)
	else (width, height + s.height)
	val newScreens = screens ++ s.screens
	for (screen <- newScreens) {
	screen.width = newWidth
	screen.height = newHeight
	screen.origin = newOrigin
	screen.screens ++= newScreens // It's a set, so there won't be duplicates.
	screen.cachedBounds = None
	}
	true
	}
	else false // Cannot merge.
	case _ => false
	}
	}
	tryMergeTowards(0, height) \|\| tryMergeTowards(0, -1) \|\| tryMergeTowards(width, 0) \|\| tryMergeTowards(-1, 0)
	}

	private def project(t: Screen) = {
	def dot(f: ForgeDirection, s: Screen) = f.offsetX * s.x + f.offsetY * s.y + f.offsetZ * s.z
	(dot(toGlobal(ForgeDirection.EAST), t), dot(toGlobal(ForgeDirection.UP), t), dot(toGlobal(ForgeDirection.SOUTH), t))
	}

	private def unproject(x: Int, y: Int, z: Int) = {
	def dot(f: ForgeDirection) = f.offsetX * x + f.offsetY * y + f.offsetZ * z
	(dot(toLocal(ForgeDirection.EAST)), dot(toLocal(ForgeDirection.UP)), dot(toLocal(ForgeDirection.SOUTH)))
	}
	}