1 files changed, 215 insertions, 0 deletions
diff --git a/libs/hump/timer.lua b/libs/hump/timer.lua
new file mode 100644
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--- /dev/null
+++ b/libs/hump/timer.lua
@@ -0,0 +1,215 @@
+--[[
+Copyright (c) 2010-2013 Matthias Richter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local Timer = {}
+Timer.__index = Timer
+
+local function _nothing_() end
+
+local function updateTimerHandle(handle, dt)
+		-- handle: {
+		--   time = <number>,
+		--   after = <function>,
+		--   during = <function>,
+		--   limit = <number>,
+		--   count = <number>,
+		-- }
+		handle.time = handle.time + dt
+		handle.during(dt, math.max(handle.limit - handle.time, 0))
+
+		while handle.time >= handle.limit and handle.count > 0 do
+			if handle.after(handle.after) == false then
+				handle.count = 0
+				break
+			end
+			handle.time = handle.time - handle.limit
+			handle.count = handle.count - 1
+		end
+end
+
+function Timer:update(dt)
+	-- timers may create new timers, which leads to undefined behavior
+	-- in pairs() - so we need to put them in a different table first
+	local to_update = {}
+	for handle in pairs(self.functions) do
+		to_update[handle] = handle
+	end
+
+	for handle in pairs(to_update) do
+		if self.functions[handle] then
+			updateTimerHandle(handle, dt)
+			if handle.count == 0 then
+				self.functions[handle] = nil
+			end
+		end
+	end
+end
+
+function Timer:during(delay, during, after)
+	local handle = { time = 0, during = during, after = after or _nothing_, limit = delay, count = 1 }
+	self.functions[handle] = true
+	return handle
+end
+
+function Timer:after(delay, func)
+	return self:during(delay, _nothing_, func)
+end
+
+function Timer:every(delay, after, count)
+	local count = count or math.huge -- exploit below: math.huge - 1 = math.huge
+	local handle = { time = 0, during = _nothing_, after = after, limit = delay, count = count }
+	self.functions[handle] = true
+	return handle
+end
+
+function Timer:cancel(handle)
+	self.functions[handle] = nil
+end
+
+function Timer:clear()
+	self.functions = {}
+end
+
+function Timer:script(f)
+	local co = coroutine.wrap(f)
+	co(function(t)
+		self:after(t, co)
+		coroutine.yield()
+	end)
+end
+
+Timer.tween = setmetatable({
+	-- helper functions
+	out = function(f) -- 'rotates' a function
+		return function(s, ...) return 1 - f(1-s, ...) end
+	end,
+	chain = function(f1, f2) -- concatenates two functions
+		return function(s, ...) return (s < .5 and f1(2*s, ...) or 1 + f2(2*s-1, ...)) * .5 end
+	end,
+
+	-- useful tweening functions
+	linear = function(s) return s end,
+	quad   = function(s) return s*s end,
+	cubic  = function(s) return s*s*s end,
+	quart  = function(s) return s*s*s*s end,
+	quint  = function(s) return s*s*s*s*s end,
+	sine   = function(s) return 1-math.cos(s*math.pi/2) end,
+	expo   = function(s) return 2^(10*(s-1)) end,
+	circ   = function(s) return 1 - math.sqrt(1-s*s) end,
+
+	back = function(s,bounciness)
+		bounciness = bounciness or 1.70158
+		return s*s*((bounciness+1)*s - bounciness)
+	end,
+
+	bounce = function(s) -- magic numbers ahead
+		local a,b = 7.5625, 1/2.75
+		return math.min(a*s^2, a*(s-1.5*b)^2 + .75, a*(s-2.25*b)^2 + .9375, a*(s-2.625*b)^2 + .984375)
+	end,
+
+	elastic = function(s, amp, period)
+		amp, period = amp and math.max(1, amp) or 1, period or .3
+		return (-amp * math.sin(2*math.pi/period * (s-1) - math.asin(1/amp))) * 2^(10*(s-1))
+	end,
+}, {
+
+-- register new tween
+__call = function(tween, self, len, subject, target, method, after, ...)
+	-- recursively collects fields that are defined in both subject and target into a flat list
+	local function tween_collect_payload(subject, target, out)
+		for k,v in pairs(target) do
+			local ref = subject[k]
+			assert(type(v) == type(ref), 'Type mismatch in field "'..k..'".')
+			if type(v) == 'table' then
+				tween_collect_payload(ref, v, out)
+			else
+				local ok, delta = pcall(function() return (v-ref)*1 end)
+				assert(ok, 'Field "'..k..'" does not support arithmetic operations')
+				out[#out+1] = {subject, k, delta}
+			end
+		end
+		return out
+	end
+
+	method = tween[method or 'linear'] -- see __index
+	local payload, t, args = tween_collect_payload(subject, target, {}), 0, {...}
+
+	local last_s = 0
+	return self:during(len, function(dt)
+		t = t + dt
+		local s = method(math.min(1, t/len), unpack(args))
+		local ds = s - last_s
+		last_s = s
+		for _, info in ipairs(payload) do
+			local ref, key, delta = unpack(info)
+			ref[key] = ref[key] + delta * ds
+		end
+	end, after)
+end,
+
+-- fetches function and generated compositions for method `key`
+__index = function(tweens, key)
+	if type(key) == 'function' then return key end
+
+	assert(type(key) == 'string', 'Method must be function or string.')
+	if rawget(tweens, key) then return rawget(tweens, key) end
+
+	local function construct(pattern, f)
+		local method = rawget(tweens, key:match(pattern))
+		if method then return f(method) end
+		return nil
+	end
+
+	local out, chain = rawget(tweens,'out'), rawget(tweens,'chain')
+	return construct('^in%-([^-]+)$', function(...) return ... end)
+	       or construct('^out%-([^-]+)$', out)
+	       or construct('^in%-out%-([^-]+)$', function(f) return chain(f, out(f)) end)
+	       or construct('^out%-in%-([^-]+)$', function(f) return chain(out(f), f) end)
+	       or error('Unknown interpolation method: ' .. key)
+end})
+
+-- Timer instancing
+function Timer.new()
+	return setmetatable({functions = {}, tween = Timer.tween}, Timer)
+end
+
+-- default instance
+local default = Timer.new()
+
+-- module forwards calls to default instance
+local module = {}
+for k in pairs(Timer) do
+	if k ~= "__index" then
+		module[k] = function(...) return default[k](default, ...) end
+	end
+end
+module.tween = setmetatable({}, {
+	__index = Timer.tween,
+	__newindex = function(k,v) Timer.tween[k] = v end,
+	__call = function(t, ...) return default:tween(...) end,
+})
+
+return setmetatable(module, {__call = Timer.new})