Initial commit

init.lua

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+-- abstract
+
+--- Abstract Engine.
+-- Main module, containing the abstract things.
+-- The API exposed here is the Abstract API.
+-- It is as the name imply abstract, and must be implemented in a backend, such as abstract.love.
+-- When required, this file will try to autodetect the engine it is running on, and load a correct backend.
+--
+-- For backend writers:
+-- If a function defined here already contains some code, this means this code is mandatory and you must put/call
+-- it in your implementation.
+-- Also, a backend file shouldn't redefine the abstract table itself but only redefine the backend-dependant fields.
+-- The API doesn't make the difference between numbers and integers, so convert to integers when needed.
+--
+-- Abstract's goal is to run everywhere with the least porting effort possible.
+-- To achieve this, the engine needs to stay simple, and only provide features that are almost sure to be
+-- available everywhere, so writing a backend should be straighforward.
+-- However, Abstract still make some small assumptions about the engine:
+-- * The engine has some kind of main loop, or at least a function called very often (may or may not be the
+--   same as the redraw screen callback).
+-- * 32bit color depth.
+--
+-- Regarding data formats, Abstract reference implemtations expect and recommend:
+-- * For images, PNG support is expected.
+-- * For audio files, OGG Vorbis support is expected.
+-- * For fonts, TTF support is expected.
+-- Theses formats are respected for the reference implementations, but Abstract may provide a script to
+-- automatically convert data formats from a project at some point.
+--
+-- Style:
+-- * tabs for indentation, spaces for esthetic whitespace (notably in comments)
+-- * no globals
+-- * UPPERCASE for constants (or maybe not).
+-- * CamelCase for class names.
+-- * lowerCamelCase is expected for everything else.
+--
+-- Implementation levels:
+-- * backend: nothing defined in abstract, must be implemented in backend
+-- * mixed: partly implemented in abstract but must be complemeted in backend
+-- * abstract: fully-working version in abstract, may or may not be redefined in backend
+-- The implementation level is indicated using the "@impl level" annotation.
+--
+-- @usage local abstract = require("abstract")
+
+local p = ... -- require path
+local abstract
+
+abstract = {
+	--- Abstract version.
+	-- @impl abstract
+	version = "0.0.1",
+
+	--- Backend name.
+	-- For consistency, only use lowercase letters [a-z] (no special char)
+	-- @impl backend
+	backend = "unknown",
+
+	--- General game paramters (some defaults).
+	-- @impl abstract
+	params = {
+		title = "Abstract Engine",
+		width = 800,
+		height = 600,
+		resizable = false,
+		resizeType = "auto"
+	},
+
+	--- Setup general game parameters.
+	-- If a parmeter is not set, a default value will be used.
+	-- This function is expected to be only called once, before doing any drawing operation.
+	-- @tparam table params the game parameters
+	-- @usage -- Default values:
+	-- abstract.setup {
+	--   title = "Abstract Engine", -- usually window title
+	--   width = 800, -- in px
+	--   height = 600, -- in px
+	--   resizable = false, -- can the game be resized?
+	--   resizeType = "auto" -- how to act on resize: "none" to do nothing (0,0 will be top-left)
+	--                                                "center" to autocenter (0,0 will be at windowWidth/2-gameWidth/2,windowHeight/2-gameHeight/2)
+	--                                                "auto" to automatically resize to the window size (coordinate system won't change)
+	-- }
+	-- @impl mixed
+	setup = function(params)
+		for k, v in pairs(params) do
+			abstract.params[k] = v
+		end
+		abstract.draw.width = params.width
+		abstract.draw.height = params.height
+	end,
+
+	--- Frames per second (the backend should update this value).
+	-- @impl backend
+	fps = 60,
+
+	--- Time since last frame (seconds)
+	-- @impl backend
+	dt = 0
+}
+
+-- We're going to require modules requiring abstract, so to avoid stack overflows we already register the abstract package
+package.loaded[p] = abstract
+
+-- External submodules
+abstract.time = require(p..".time")
+abstract.draw = require(p..".draw")
+abstract.audio = require(p..".audio")
+abstract.input = require(p..".input")
+abstract.scene = require(p..".scene")
+abstract.event = require(p..".event")
+
+-- Backend engine autodetect and load
+if love then
+	require(p..".backend.love")
+elseif package.loaded["ctr"] then
+	require(p..".backend.ctrulua")
+end
+
+return abstract