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-rw-r--r--honey/ecs/ecs.lua136
-rw-r--r--honey/ecs/ecs.test.lua206
-rw-r--r--honey/notes.md18
3 files changed, 246 insertions, 114 deletions
diff --git a/honey/ecs/ecs.lua b/honey/ecs/ecs.lua
index dda99cb..d7eb4ac 100644
--- a/honey/ecs/ecs.lua
+++ b/honey/ecs/ecs.lua
@@ -1,6 +1,6 @@
math.randomseed(os.time())
-local glm = require 'honey.glm'
+local testing, glm = pcall(require, 'honey.glm')
local module = {}
setmetatable(module, {__index=_G})
@@ -87,9 +87,11 @@ function EntityDb.load(self, filename)
self:createEntity(id)
self:addComponents(id, components)
end,
- Vec3 = glm.Vec3,
- Mat4 = glm.Mat4,
}
+ if not testing then
+ env.Vec3 = glm.Vec3
+ env.Mat4 = glm.Mat4
+ end
local f, err = loadfile(filename)
if not f then error(err) end
setfenv(f, env)
@@ -209,6 +211,35 @@ function EntityDb.deleteEntity(self, id)
end
+--===== Systems =====--
+
+System = {}
+System.__index = System
+
+function System.new(_, name, f)
+ local self = {
+ name = name,
+ f = f,
+ dependencies = {},
+ }
+ setmetatable(self, System)
+ return self
+end
+setmetatable(System, {__call=System.new})
+
+function System.addDependency(self, system)
+ self.dependencies[system.name] = true
+ return self
+end
+
+function System.addDependencies(self, systems)
+ for _, system in ipairs(systems) do
+ self:addDependency(system)
+ end
+ return self
+end
+
+
--===== SystemDb =====--
SystemDb = {}
@@ -218,7 +249,9 @@ SystemDb.__index = SystemDb
function SystemDb.new(_, entityDb)
local self = {
systems = {},
- sorted = {},
+ params = {},
+ sort = {},
+ dangling = {},
entityDb = entityDb,
}
setmetatable(self, SystemDb)
@@ -227,49 +260,90 @@ end
setmetatable(SystemDb, {__call=SystemDb.new})
-local function systemId()
- local template = "xx:xx:xx"
- return string.gsub(template, "x", function(c)
- return string.format("%x", random(0, 0xf))
- end)
-end
+-- depth-first topological sort
+-- thank god for wikipedia
+local function tsort(systems)
+ local graph = {}
+ local count = 0
+ for _, system in pairs(systems) do
+ graph[system.name] = { name=system.name, dependencies=system.dependencies, tmark=false, pmark=false }
+ count = count+1
+ end
+ local sort = {}
+ local dangling = {}
-function SystemDb.addSystem(self, systemFunc, params)
- local system
- if type(systemFunc) == "table" then
- system = systemFunc
- else
- local params = params or {}
- params.db = self.entityDb
- system = systemFunc(params)
+ local visit
+ visit = function(node)
+ if node == nil then
+ -- dangling dependency, ignore for now
+ return true
+ end
+ if node.pmark then return false end
+ if node.tmark then error("dependency cycle detected") end
+
+ node.tmark = true
+
+ for name in pairs(node.dependencies) do
+ local dangle = visit(graph[name])
+ if dangle then
+ dangling[name] = true
+ end
+ end
+
+ node.tmark = false
+ node.pmark = true
+ count = count-1
+ table.insert(sort, node.name)
end
- local id = systemId()
- self.systems[id] = system
- table.insert(self.sorted, id)
- self:sort()
- return id
+ for _, node in pairs(graph) do
+ visit(node)
+ if count == 0 then break end
+ end
+
+ return sort, dangling
end
-function SystemDb.sort(self)
- table.sort(self.sorted, function(a, b) return (self.systems[a].priority or 100) < (self.systems[b].priority or 100) end)
+function SystemDb.addSystems(self, systems, params)
+ for _, system in ipairs(systems) do
+ self.systems[system.name] = system
+ self.params[system.name] = params
+ end
+ self.sort, self.dangling = tsort(self.systems)
+ return self
end
function SystemDb.update(self, dt)
- for _, system in ipairs(self.sorted) do
- self.systems[system]:update(dt)
+ -- check for dangling dependencies
+ local dangle = ""
+ for dependency in pairs(self.dangling) do
+ print(dependency)
+ dangle = dangle .. string.format(
+ "unresolved dangling dependency: %s\n",
+ dependency
+ )
+ end
+ if dangle ~= "" then
+ error(dangle)
+ end
+
+
+ for _, name in ipairs(self.sort) do
+ local system = self.systems[name]
+ local params = self.params[name]
+ system.f(self.db, dt, params)
end
end
-function SystemDb.removeSystem(self, id)
- self.systems[id] = nil
- for i=#self.sorted,1,-1 do
- if self.sorted[i] == id then table.remove(self.sorted, i) end
+function SystemDb.removeSystems(self, systems)
+ for _, system in pairs(systems) do
+ self.systems[system.name] = nil
end
+ self.sort, self.dangling = tsort(self.systems)
end
diff --git a/honey/ecs/ecs.test.lua b/honey/ecs/ecs.test.lua
index 74e27dc..5d0b89e 100644
--- a/honey/ecs/ecs.test.lua
+++ b/honey/ecs/ecs.test.lua
@@ -17,59 +17,6 @@ end
local ecs = require 'ecs'
---===== Component tests =====--
-
-local Component = ecs.Component
-
-test("factories work as expected", function()
- local factory = Component.newFactory("health", { percent=100 })
- local comp1 = factory()
- assert(comp1.__type == "health", "bad component type for comp1")
- assert(comp1.percent == 100, "bat percent for comp1")
-
- local comp2 = factory{ percent=50 }
- assert(comp2.__type == "health", "bad component type for comp2")
- assert(comp2.percent == 50, "bad percent for comp2")
-
- local success = pcall(function()
- comp2.dne = 5
- end)
- assert(not success, "incorrectly succeeded in setting comp2.dne")
-
- local success = pcall(function()
- local comp3 = factory{ percent = 44, something = 2 }
- end)
- assert(not success, "incorrectly succeeded in creating comp3")
-end)
-
-
-test("components serialize as expected", function()
- local position = Component.newFactory("position", { x=0, y=0, z=0 })
- local comp = position{x=10, y=15, z=10}
- local str = tostring(comp)
- local tbl = (loadstring("return " .. str))()
- assert(tbl.__type == "position", "bad type")
- assert(tbl.x == 10, "bad x")
- assert(tbl.y == 15, "bad y")
- assert(tbl.z == 10, "bad z")
-end)
-
-
-test("components serialize successfully with subcomponents", function()
- local position = Component.newFactory("position", { x=0, y=0, z=0 })
- local player = Component.newFactory("player", { name="", position={} })
-
- local p = player{ name="hannah", position=position{x=10, y=9, z=8} }
- local tbl = (loadstring("return " .. tostring(p)))()
- assert(tbl.__type == "player")
- assert(tbl.name == "hannah")
- assert(tbl.position.__type == "position")
- assert(tbl.position.x == 10)
- assert(tbl.position.y == 9)
- assert(tbl.position.z == 8)
-end)
-
-
--===== EntityDb tests =====--
local EntityDb = ecs.EntityDb
@@ -233,47 +180,142 @@ end)
local SystemDb = ecs.SystemDb
-test("addSystem() correctly sorts systems", function()
+test("addSystems() correctly sorts systems", function()
local sdb = SystemDb(nil)
local str = ""
- sdb:addSystem(function () return {
- update=function(self, dt) str = str .. "c" end,
- priority = 3,
- } end)
- sdb:addSystem{
- update=function(self, dt) str = "a" end,
- priority = 1,
- }
- sdb:addSystem{
- update=function(self, dt) str = str .. "b" end,
- priority = 2,
- }
+
+ local c = ecs.System("c", function(db, dt, params)
+ str = str .. "c"
+ end)
+
+ local a = ecs.System("a", function(db, dt, params)
+ str = str .. "a"
+ end)
+
+ local b = ecs.System("b", function(db, dt, params)
+ str = str .. "b"
+ end)
+
+ b:addDependency(a)
+ c:addDependency(b)
+
+ sdb:addSystems({c, a, b}, nil)
+
sdb:update(0)
assert(str == "abc")
end)
-test("removeSystem() correctly handles things", function()
+test("addSystems() fails on dependency loop", function()
+ local a = ecs.System("a", nil)
+ local b = ecs.System("b", nil)
+ local c = ecs.System("c", nil)
+
+ a:addDependency(c)
+ b:addDependency(a)
+ c:addDependency(b)
+
+ sdb = SystemDb(nil)
+ local success = pcall(sdb,addSystems, sdb, {c, a, b}, nil)
+ assert(success == false)
+end)
+
+
+test("addSystems() correctly inserts additional systems", function()
+ local str = ""
local sdb = SystemDb(nil)
+
+ local c = ecs.System("c", function(db, dt, params)
+ str = str .. "c"
+ end)
+ local a = ecs.System("a", function(db, dt, params)
+ str = str .. "a"
+ end)
+ local b = ecs.System("b", function(db, dt, params)
+ str = str .. "b"
+ end)
+
+ b:addDependency(a)
+ c:addDependency(b)
+
+ sdb:addSystems({c, a, b}, nil)
+
+ local d = ecs.System("d", function(db, dt, params)
+ str = str .. "d"
+ end)
+ local e = ecs.System("e", function(db, dt, params)
+ str = str .. "e"
+ end)
+
+ d:addDependency(c)
+ e:addDependency(d)
+
+ sdb:addSystems({e, d}, nil)
+ sdb:update(0)
+ assert(str == "abcde")
+end)
+
+
+test("addSystems() correctly handles dangling dependencies", function()
local str = ""
- sdb:addSystem(function () return {
- update=function(self, dt) str = str .. "c" end,
- priority = 3,
- } end)
- sdb:addSystem{
- update=function(self, dt) str = "a" end,
- priority = 1,
- }
- local id = sdb:addSystem{
- update=function(self, dt) str = str .. "b" end,
- priority = 2,
- }
+ local sdb = SystemDb(nil)
+
+ local c = ecs.System("c", function(db, dt, params)
+ str = str .. "c"
+ end)
+ local a = ecs.System("a", function(db, dt, params)
+ str = str .. "a"
+ end)
+ local b = ecs.System("b", function(db, dt, params)
+ str = str .. "b"
+ end)
+
+ b:addDependency(a)
+ c:addDependency(b)
+
+ local d = ecs.System("d", function(db, dt, params)
+ str = str .. "d"
+ end)
+ local e = ecs.System("e", function(db, dt, params)
+ str = str .. "e"
+ end)
+
+ d:addDependency(c)
+ e:addDependency(d)
+
+ sdb:addSystems({e, d}, nil)
+
+ local success = pcall(sdb.update, sdb, nil)
+ assert(success == false)
+
+ sdb:addSystems({c, a, b}, nil)
+
sdb:update(0)
- assert(str == "abc")
+ assert(str == "abcde")
+end)
+
+
+
+
+test("removeSystem() correctly handles things", function()
+ local sdb = SystemDb(nil)
+ local num = 1
+
+
+ local two = ecs.System("x2", function(db, dt, p) num = num*2 end)
+ local three = ecs.System("x3", function(db, dt, p) num = num*3 end)
+ local five = ecs.System("x5", function(db, dt, p) num = num*5 end)
+
+ sdb:addSystems({two, three, five}, nil)
+
+ sdb:update(0)
+ assert(num == 30)
+
+ num = 1
- sdb:removeSystem(id)
+ sdb:removeSystems({three})
sdb:update(1)
- assert(str == "ac")
+ assert(num == 10)
end)
diff --git a/honey/notes.md b/honey/notes.md
index 5dd25e7..16ccc49 100644
--- a/honey/notes.md
+++ b/honey/notes.md
@@ -13,11 +13,27 @@ assets are cached. each asset type has a module (e.g. `mesh`, `image`, `sound`,
individual assets may have additional functions.
+entities
+--------
+
+entities are just identifiers. they are UUID strings. they index into components.
+
+
+components
+-----------
+
+components are data tables. they are supposed to contain only booleans, numbers, strings, and tables containing the other three types; they may contain additional state data (e.g. userdata, functions, etc) if they are prefixed by an underscore, and these things are transient and will have to be re-created on the next load from the bools, strings, numbers, and tables. the one exception to this rule is glm types; components *are* allowed to contain Vec3/Mat4/Quaternion/etc. (the glm types serialize nicely so this is not problematic.)
+
+
systems
-------
-systems are pure functions (NOT closures!!). they can be embedded in tables that indicate dependencies, i.e. which other systems *must* execute before them in order for things to work correctly. They have a signature like
+systems are pure functions (NOT closures!!). they must be embedded in tables that give them a name and indicate their dependencies, i.e. which other systems *must* execute before them in order for things to work correctly. They have a signature like
> `system(db, dt, [params])`
where params is a table. all parameters, including the params table, are passed in by the systemdb every frame; the system should NEVER close over them.
+
+(i may allow an exception to the system closure rule for the sake of physics update frequencies, but in general i would prefer to avoid them at all costs.)
+
+system modules should return an array of any systems needed for that conceptual system to work; the system db will add them all as one "system."