108 lines
3.5 KiB
Lua
108 lines
3.5 KiB
Lua
--[[
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Copyright (c) 2010-2013 Matthias Richter
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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Except as contained in this notice, the name(s) of the above copyright holders
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shall not be used in advertising or otherwise to promote the sale, use or
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other dealings in this Software without prior written authorization.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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]]--
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local function __NULL__() end
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-- default gamestate produces error on every callback
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local state_init = setmetatable({leave = __NULL__},
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{__index = function() error("Gamestate not initialized. Use Gamestate.switch()") end})
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local stack = {state_init}
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local initialized_states = setmetatable({}, {__mode = "k"})
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local state_is_dirty = true
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local GS = {}
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function GS.new(t) return t or {} end -- constructor - deprecated!
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local function change_state(stack_offset, to, ...)
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local pre = stack[#stack]
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-- initialize only on first call
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;(initialized_states[to] or to.init or __NULL__)(to)
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initialized_states[to] = __NULL__
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stack[#stack+stack_offset] = to
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state_is_dirty = true
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return (to.enter or __NULL__)(to, pre, ...)
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end
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function GS.switch(to, ...)
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assert(to, "Missing argument: Gamestate to switch to")
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assert(to ~= GS, "Can't call switch with colon operator")
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;(stack[#stack].leave or __NULL__)(stack[#stack])
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return change_state(0, to, ...)
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end
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function GS.push(to, ...)
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assert(to, "Missing argument: Gamestate to switch to")
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assert(to ~= GS, "Can't call push with colon operator")
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return change_state(1, to, ...)
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end
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function GS.pop(...)
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assert(#stack > 1, "No more states to pop!")
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local pre, to = stack[#stack], stack[#stack-1]
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stack[#stack] = nil
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;(pre.leave or __NULL__)(pre)
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state_is_dirty = true
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return (to.resume or __NULL__)(to, pre, ...)
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end
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function GS.current()
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return stack[#stack]
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end
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-- fetch event callbacks from love.handlers
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local all_callbacks = { 'draw', 'errhand', 'update' }
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for k in pairs(love.handlers) do
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all_callbacks[#all_callbacks+1] = k
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end
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function GS.registerEvents(callbacks)
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local registry = {}
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callbacks = callbacks or all_callbacks
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for _, f in ipairs(callbacks) do
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registry[f] = love[f] or __NULL__
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love[f] = function(...)
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registry[f](...)
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return GS[f](...)
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end
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end
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end
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-- forward any undefined functions
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setmetatable(GS, {__index = function(_, func)
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-- call function only if at least one 'update' was called beforehand
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-- (see issue #46)
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if not state_is_dirty or func == 'update' then
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state_is_dirty = false
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return function(...)
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return (stack[#stack][func] or __NULL__)(stack[#stack], ...)
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end
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end
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return __NULL__
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end})
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return GS
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