ubiquitousse.util

util.lua

@@ -0,0 +1,52 @@
+-- ubiquitousse.util
+
+--- Various functions useful for game developement.
+-- No dependicy on either ubiquitousse or a ubiquitousse backend.
+local util
+util = {
+	--- AABB collision check.
+	-- @tparam number x1 first rectangle top-left x coordinate
+	-- @tparam number y1 first rectangle top-left y coordinate
+	-- @tparam number w1 first rectangle width
+	-- @tparam number h1 first rectangle height
+	-- @tparam number x2 second rectangle top-left x coordinate
+	-- @tparam number y2 second rectangle top-left y coordinate
+	-- @tparam number w2 second rectangle width
+	-- @tparam number h2 second rectangle height
+	-- @treturn true if the objects collide, false otherwise
+	aabb = function(x1, y1, w1, h1, x2, y2, w2, h2)
+		if w1 < 0 then x1 = x1 + w1; w1 = -w1 end
+		if h1 < 0 then y1 = y1 + h1; h1 = -h1 end
+		if w2 < 0 then x2 = x2 + w2; w2 = -w2 end
+		if h2 < 0 then y2 = y2 + h2; h2 = -h2 end
+		return x1 + w1 >= x2 and x1 <= x2 + w2 and
+		       y1 + h1 >= y2 and y1 <= y2 + h2
+	end,
+
+	--- Remove the first occurence of an element in a table.
+	-- @tparam table t the table
+	-- @param x the element to remove
+	-- @return x
+	remove = function(t, x)
+		for i, v in ipairs(t) do
+			if v == x then
+				table.remove(t, i)
+				break
+			end
+		end
+		return x
+	end,
+
+	--- Returns a new table where the keys and values have been inverted.
+	-- @tparam table t the table
+	-- @treturn table the inverted table
+	invert = function(t)
+		local r = {}
+		for k, v in pairs(t) do
+			r[v] = k
+		end
+		return r
+	end
+}
+
+return util