event loop

1 files changed, 96 insertions, 0 deletions

diff --git a/evloop.lua b/evloop.lua
new file mode 100644
index 0000000..c72f920
--- /dev/null
+++ b/evloop.lua
@@ -0,0 +1,96 @@
+local M = {}
+M.__index = M
+
+local queue = {}
+
+local function resume_task(task, e)
+	if coroutine.status(task.co) == "dead" then
+		return false
+	end
+
+	if task.filter then
+		for _, f in ipairs(task.filter) do
+			if f == e[1] then
+				goto resume
+			end
+		end
+		return true
+	end
+
+	::resume::
+	local ok, ret = coroutine.resume(task.co, e)
+	if not ok then
+		io.stderr:write(debug.traceback(task.co, ret)..'\n\n')
+		error "error in event loop"
+	end
+	task.filter = ret
+	return coroutine.status(task.co) ~= "dead"
+end
+
+local function create_task(fn)
+	local task = {}
+	task.co = coroutine.create(fn)
+	return task
+end
+
+function M.poll(...)
+	local filter = {...}
+	return unpack(coroutine.yield(#filter > 0 and filter))
+end
+
+function M.sleep(secs)
+	local t = 0
+	while t < secs do
+		local e, dt = M.poll "update"
+		t = t + dt
+	end
+	return t
+end
+
+function M.queue(...)
+	table.insert(queue, {...})
+end
+
+function M.mainloop(start)
+	local main = create_task(function()
+		start()
+	end)
+
+	return function()
+		love.event.pump()
+		local es = love.event.poll()
+		while true do
+			local e = {es()}
+			if not e[1] then break end
+			if e[1] == "quit" then
+				if not love.quit or not love.quit() then
+					return e[2] or 0
+				end
+			end
+			if love.handlers[e[1]] then
+				love.handlers[e[1]](unpack(e, 2))
+			end
+			table.insert(queue, e)
+		end
+
+		local q = queue
+		queue = {}
+		for i, e in ipairs(q) do
+			if not resume_task(main, e) then return end
+		end
+
+		local dt = love.timer.step()
+		if not resume_task(main, {"update", dt}) then return end
+
+		if love.graphics and love.graphics.isActive() then
+			love.graphics.origin()
+			love.graphics.clear(love.graphics.getBackgroundColor())
+			if not resume_task(main, {"draw", dt}) then return end
+			love.graphics.present()
+		end
+
+		love.timer.sleep(0.001)
+	end
+end
+
+return M