From de08e7d87d5d0d4e9edd4943c7b07adcc479c311 Mon Sep 17 00:00:00 2001
From: Tangent Fox <tangentfoxy@gmail.com>
Date: Mon, 1 Oct 2018 09:12:32 -0700
Subject: [PATCH] v1

---
 Fluid.lua  | 112 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Fluid.moon |  77 ++++++++++++++++++++++++++++++++++++
 test.lua   |  65 +++++++++++++++++++++++++++++++
 test.moon  |  42 ++++++++++++++++++++
 4 files changed, 296 insertions(+)
 create mode 100644 Fluid.lua
 create mode 100644 Fluid.moon
 create mode 100644 test.lua
 create mode 100644 test.moon

diff --git a/Fluid.lua b/Fluid.lua
new file mode 100644
index 0000000..ea1963a
--- /dev/null
+++ b/Fluid.lua
@@ -0,0 +1,112 @@
+local Fluid
+do
+  local _class_0
+  local _base_0 = {
+    update = function(self, dt)
+      local leak = 0
+      local _list_0 = self.breaches
+      for _index_0 = 1, #_list_0 do
+        local breach = _list_0[_index_0]
+        local rate = (self.pressure - breach.pressure) * (breach.size / self.volume) * dt
+        leak = leak + rate
+        breach.pressure = breach.pressure + (rate * (self.volume / breach.volume))
+        if breach.pressure < 0 then
+          breach.pressure = 0
+        end
+        local amount = breach.pressure * breach.volume
+        local modifier = 1 - self.volume * rate / amount
+        for item, percentage in pairs(breach.contents) do
+          breach.contents[item] = percentage * modifier
+        end
+        for item, percentage in pairs(self.contents) do
+          percentage = (self.volume * rate * percentage) / amount
+          if breach.contents[item] then
+            breach.contents[item] = breach.contents[item] + percentage
+          else
+            breach.contents[item] = percentage
+          end
+        end
+      end
+      self.pressure = self.pressure - leak
+      for i = 1, #self.breaches do
+        if self.breaches[i].pressure > self.pressure then
+          local other = table.remove(self.breaches, i)
+          other:breach(self, other.size)
+          i = i - 1
+        end
+      end
+    end,
+    amount = function(self, key)
+      if key then
+        if self.contents[key] then
+          return self.volume * self.pressure * self.contents[key]
+        else
+          return 0
+        end
+      else
+        return self.volume * self.pressure
+      end
+    end,
+    remove = function(self, key, amount)
+      if amount == nil then
+        amount = 1
+      end
+      local total = self:amount(key)
+      if total >= amount then
+        local percentage = amount / total
+        self.contents[key] = self.contents[key] - (self.contents[key] * percentage)
+        percentage = amount / self:amount()
+        self.pressure = self.pressure - (self.pressure * percentage)
+        for item, p in pairs(self.contents) do
+          self.contents[item] = self.contents[item] + (p * percentage)
+        end
+        return true
+      else
+        return false
+      end
+    end,
+    breach = function(self, other, size)
+      if other.pressure > self.pressure then
+        return other:breach(self, size)
+      else
+        other.size = size or 1
+        return table.insert(self.breaches, other)
+      end
+    end,
+    print = function(self)
+      print("Volume", self.volume, "Pressure", self.pressure, "#", self:amount())
+      local percentage, amount = 0, 0
+      for k, v in pairs(self.contents) do
+        local x = self:amount(k)
+        print(k, v, x)
+        percentage = percentage + v
+        amount = amount + x
+      end
+      return print("", "Total:", percentage, amount)
+    end
+  }
+  _base_0.__index = _base_0
+  _class_0 = setmetatable({
+    __init = function(self, opts)
+      if opts == nil then
+        opts = { }
+      end
+      self.volume = opts.volume or 1
+      self.pressure = opts.pressure or 1
+      self.contents = opts.contents or { }
+      self.breaches = { }
+    end,
+    __base = _base_0,
+    __name = "Fluid"
+  }, {
+    __index = _base_0,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  Fluid = _class_0
+  return _class_0
+end
diff --git a/Fluid.moon b/Fluid.moon
new file mode 100644
index 0000000..9ed2c84
--- /dev/null
+++ b/Fluid.moon
@@ -0,0 +1,77 @@
+-- it is up to user to ensure that total breached volume is lower
+--  than the total volume
+class Fluid
+  new: (opts={}) =>
+    @volume = opts.volume or 1
+    @pressure = opts.pressure or 1
+    @contents = opts.contents or {}
+    -- breaches stored on high pressure side of Fluids
+    @breaches = {}
+
+  update: (dt) =>
+    leak = 0 -- total leak rate (pressure)
+    for breach in *@breaches
+      -- difference in pressure * relative size of hole
+      rate = (@pressure - breach.pressure) * (breach.size / @volume) * dt
+      leak += rate
+      breach.pressure += rate * (@volume / breach.volume)
+      breach.pressure = 0 if breach.pressure < 0
+      amount = breach.pressure * breach.volume
+
+      modifier = 1 - @volume * rate / amount
+      for item, percentage in pairs breach.contents
+        breach.contents[item] = percentage * modifier
+
+      for item, percentage in pairs @contents
+        percentage = (@volume * rate * percentage) / amount
+        if breach.contents[item]
+          breach.contents[item] += percentage
+        else
+          breach.contents[item] = percentage
+
+    @pressure -= leak
+
+    for i = 1, #@breaches
+      if @breaches[i].pressure > @pressure
+        other = table.remove @breaches, i
+        other\breach(@, other.size)
+        i -= 1
+
+  amount: (key) =>
+    if key
+      if @contents[key]
+        return @volume * @pressure * @contents[key]
+      else
+        return 0
+    else
+      return @volume * @pressure
+
+  remove: (key, amount=1) =>
+    total = @amount key
+    if total >= amount
+      percentage = amount / total
+      @contents[key] -= @contents[key] * percentage
+      percentage = amount / @amount!
+      @pressure -= @pressure * percentage
+      for item, p in pairs @contents
+        @contents[item] += p * percentage
+      return true
+    else
+      return false
+
+  breach: (other, size) =>
+    if other.pressure > @pressure
+      other\breach(@, size)
+    else
+      other.size = size or 1
+      table.insert @breaches, other
+
+  print: =>
+    print "Volume", @volume, "Pressure", @pressure, "#", @amount!
+    percentage, amount = 0, 0
+    for k,v in pairs @contents
+      x = @amount k
+      print k, v, x
+      percentage += v
+      amount += x
+    print "", "Total:", percentage, amount
diff --git a/test.lua b/test.lua
new file mode 100644
index 0000000..cf4aeac
--- /dev/null
+++ b/test.lua
@@ -0,0 +1,65 @@
+local Fluid = require("Fluid")
+local copy
+copy = function(tab)
+  local new = { }
+  for k, v in pairs(tab) do
+    new[k] = v
+  end
+  return new
+end
+local air = {
+  nitrogen = 0.775,
+  oxygen = 0.21,
+  argon = 0.01,
+  co2 = 0.005
+}
+local A = Fluid({
+  volume = 32,
+  pressure = 12,
+  contents = copy(air)
+})
+local B = Fluid({
+  volume = 1100,
+  pressure = 2,
+  contents = {
+    hydrogen = 0.9,
+    helium = 0.1
+  }
+})
+A:print()
+B:print()
+A:breach(B, 5)
+A:update(1)
+B:update(1)
+A:print()
+B:print()
+print("...")
+local Air = Fluid({
+  volume = 1000,
+  pressure = 1,
+  contents = copy(air)
+})
+local Vacuum = Fluid({
+  volume = math.huge,
+  pressure = 0
+})
+Air:breach(Vacuum)
+for i = 1, 10 do
+  Air:print()
+  Air:update(i)
+end
+print("...")
+Air = Fluid({
+  volume = 1000,
+  pressure = 1,
+  contents = copy(air)
+})
+Air:print()
+local half = Air:amount("oxygen") / 2
+print("Removing half the oxygen (" .. tostring(half) .. ").")
+Air:remove("oxygen", half)
+Air:print()
+local full = Air:amount("oxygen")
+print("Removing the rest (" .. tostring(full) .. ").")
+Air:remove("oxygen", full)
+return Air:print()
diff --git a/test.moon b/test.moon
new file mode 100644
index 0000000..43fbbfc
--- /dev/null
+++ b/test.moon
@@ -0,0 +1,42 @@
+Fluid = require "Fluid"
+
+copy = (tab) ->
+  new = {}
+  for k,v in pairs tab
+    new[k] = v
+  return new
+
+air = { nitrogen: 0.775, oxygen: 0.21, argon: 0.01, co2: 0.005 }
+
+A = Fluid volume: 32, pressure: 12, contents: copy air
+B = Fluid volume: 1100, pressure: 2, contents: { hydrogen: 0.9, helium: 0.1 }
+A\print!
+B\print!
+A\breach(B, 5)
+A\update 1
+B\update 1
+A\print!
+B\print!
+
+print "..."
+
+Air = Fluid volume: 1000, pressure: 1, contents: copy air
+Vacuum = Fluid volume: math.huge, pressure: 0
+
+Air\breach Vacuum
+for i = 1, 10
+  Air\print!
+  Air\update i
+
+print "..."
+
+Air = Fluid volume: 1000, pressure: 1, contents: copy air
+Air\print!
+half = Air\amount("oxygen") / 2
+print "Removing half the oxygen (#{half})."
+Air\remove "oxygen", half
+Air\print!
+full = Air\amount "oxygen"
+print "Removing the rest (#{full})."
+Air\remove "oxygen", full
+Air\print!