From 45dbe47d17303050cbea7c2c51e838acfe21c2fb Mon Sep 17 00:00:00 2001
From: sanine-a <sanine.not@pm.me>
Date: Tue, 28 Mar 2023 16:35:22 -0500
Subject: add cached mesh loading

---
 honey/ecs.lua | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 87 insertions(+), 6 deletions(-)

(limited to 'honey/ecs.lua')

diff --git a/honey/ecs.lua b/honey/ecs.lua
index 8aa5c5c..72cc41d 100644
--- a/honey/ecs.lua
+++ b/honey/ecs.lua
@@ -84,6 +84,7 @@ end
 setmetatable(EntityDb, {__call=EntityDb.new})
 
 
+-- check if a given entity id is legitimate
 function EntityDb.checkIsValid(self, id)
 	if not self.entities[id] then
 		error(string.format("invalid entity id: %s", tostring(id)))
@@ -91,22 +92,29 @@ function EntityDb.checkIsValid(self, id)
 end
 
 
-local function uid()
-	local template ='xxxx:xxxx:xxxx'
-	return string.gsub(template, 'x', function (c)
-		local v = math.random(0, 0xf)
+local random = math.random
+local function uuid()
+	local template ='xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
+	return string.gsub(template, '[xy]', function (c)
+		local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
 		return string.format('%x', v)
 	end)
 end
-function EntityDb.createEntity(self)
-	local id = uid()
+
+
+-- create a new entity
+function EntityDb.createEntity(self, id)
+	local id = id or uuid() -- allow inserting entities at preset ids for loading
 	self.entities[id] = true
 	return id
 end
 
 
+-- add a component to an entity
 function EntityDb.addComponent(self, id, name, value)
 	self:checkIsValid(id)
+	
+	-- create the relevant component table if it doesn't exist
 	if not self.components[name] then
 		self.components[name] = { count=0 }
 	end
@@ -124,6 +132,7 @@ local function shallowCopy(tbl)
 end
 
 
+-- get all entities with a given component
 function EntityDb.queryComponent(self, name)
 	local query = shallowCopy(self.components[name])
 	query.count = nil
@@ -131,6 +140,7 @@ function EntityDb.queryComponent(self, name)
 end
 
 
+-- get all components associated with an entity
 function EntityDb.queryEntity(self, id)
 	self:checkIsValid(id)
 	local query = {}
@@ -141,6 +151,14 @@ function EntityDb.queryEntity(self, id)
 end
 
 
+-- get a specific component from an entity
+function EntityDb.getComponent(self, id, name)
+	self:checkIsValid(id)
+	return self.components[name][id]
+end
+
+
+-- remove a component from an entity
 function EntityDb.removeComponent(self, id, name)
 	self:checkIsValid(id)
 	local component = self.components[name]
@@ -154,6 +172,7 @@ function EntityDb.removeComponent(self, id, name)
 end
 
 
+-- remove an entity from the db
 function EntityDb.deleteEntity(self, id)
 	self:checkIsValid(id)
 	for name in pairs(self.components) do
@@ -162,4 +181,66 @@ function EntityDb.deleteEntity(self, id)
 	self.entities[id] = nil
 end
 
+
+--===== SystemDb =====--
+
+SystemDb = {}
+SystemDb.__index = SystemDb
+
+
+function SystemDb.new(_)
+	local self = {
+		systems = {},
+		sorted = {},
+	}
+	setmetatable(self, SystemDb)
+	return self
+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
+
+
+function SystemDb.addSystem(self, systemFunc, params)
+	local system
+	if type(systemFunc) == "table" then
+		system = systemFunc
+	else
+		system = systemFunc(params)
+	end
+
+	local id = systemId()
+	self.systems[id] = system
+	table.insert(self.sorted, id)
+	self:sort()
+	return id
+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)
+end
+
+
+function SystemDb.update(self, dt)
+	for _, system in ipairs(self.sorted) do
+		self.systems[system]:update(dt)
+	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
+	end
+end
+
+
 return module
-- 
cgit v1.2.1