Initial commit

draw.lua

@@ -0,0 +1,72 @@
+-- abstract.draw
+local abstract = require((...):match("^(.-abstract)%."))
+
+--- The drawing functions: everything that affect the display/window.
+-- The coordinate system used is:
+-- 
+--  (0,0) +---> (x)
+--        |
+--        |
+--        v (y)
+--
+-- x and y values can be float, so make sure to perform math.floor if your engine only support
+-- integer coordinates.
+return {
+	--- Sets the drawing color
+	-- @tparam number r the red component (0-255)
+	-- @tparam number g the green component (0-255)
+	-- @tparam number b the blue component (0-255)
+	-- @tparam[opt=255] number a the alpha (opacity) component (0-255)
+	-- @impl backend
+	color = function(r, g, b, a) end,
+
+	--- Draws some text.
+	-- @tparam number x x top-left coordinate of the text
+	-- @tparam number y y top-left coordinate of the text
+	-- @tparam string text the text to draw. UTF-8 format, convert if needed.
+	-- @impl backend
+	text = function(x, y, text) end,
+
+	--- Draws a line.
+	-- @tparam number x1 line start x coordinate
+	-- @tparam number y1 line start y coordinate
+	-- @tparam number x2 line end x coordinate
+	-- @tparam number y2 line end y coordinate
+	-- @impl backend
+	line = function(x1, y1, x2, y2) end,
+
+	--- Draws a filled rectangle
+	-- @tparam number x rectangle top-left x coordinate
+	-- @tparam number y rectangle top-left x coordinate
+	-- @tparam number width rectangle width
+	-- @tparam number height rectangle height
+	-- @impl backend
+	rectangle = function(x, y, width, height) end,
+
+	--- Enables the scissor test.
+	-- When enabled, every pixel drawn outside of the scissor rectangle is discarded.
+	-- When called withou arguments, it disables the scissor test.
+	-- @tparam number x rectangle top-left x coordinate
+	-- @tparam number y rectangle top-left x coordinate
+	-- @tparam number width rectangle width
+	-- @tparam number height rectangle height
+	-- @impl backend
+	scissor = function(x, y, width, height) end,
+
+	--- The drawing area width, in pixels.
+	-- @impl backend
+	width = abstract.params.width,
+
+	--- The drawing area height, in pixels.
+	-- @impl backend
+	height = abstract.params.height,
+
+	-- TODO: doc & api
+	push = function() end,
+	pop = function() end,
+	polygon = function(...) end,
+	circle = function(x, y, radius) end,
+	translate = function(x, y) end,
+	font = function(filename) end,
+	image = function(filename) end,
+}