wired switches and doors

wire.lua

@@ -0,0 +1,55 @@
+local Wire = {
+	NORTH = 1,
+	EAST = 2,
+	SOUTH = 4,
+	WEST = 8,
+}
+
+Wire.directions = {
+	{bit = Wire.NORTH, opposite = Wire.SOUTH, x = 0, y = -1},
+	{bit = Wire.EAST, opposite = Wire.WEST, x = 1, y = 0},
+	{bit = Wire.SOUTH, opposite = Wire.NORTH, x = 0, y = 1},
+	{bit = Wire.WEST, opposite = Wire.EAST, x = -1, y = 0},
+}
+
+function Wire.has(mask, bit)
+	return math.floor((mask or 0) / bit) % 2 == 1
+end
+
+function Wire.add(mask, bit)
+	mask = mask or 0
+	return Wire.has(mask, bit) and mask or mask + bit
+end
+
+function Wire.remove(mask, bit)
+	mask = mask or 0
+	return Wire.has(mask, bit) and mask - bit or mask
+end
+
+function Wire.directionBetween(a, b)
+	local dx, dy = b.x - a.x, b.y - a.y
+	for _, direction in ipairs(Wire.directions) do
+		if direction.x == dx and direction.y == dy then return direction end
+	end
+end
+
+-- Circuit colours are deliberately independent from the RGB gameplay layers.
+-- A stable hash makes a route keep the same editor colour after save/load.
+local palette = {
+	{1.00, 0.78, 0.20},
+	{0.20, 0.92, 0.92},
+	{1.00, 0.42, 0.72},
+	{0.62, 1.00, 0.32},
+	{0.72, 0.55, 1.00},
+	{1.00, 0.55, 0.22},
+}
+
+function Wire.color(circuitId)
+	local hash = 0
+	for index = 1, #(circuitId or "") do
+		hash = (hash * 33 + circuitId:byte(index)) % 65521
+	end
+	return palette[hash % #palette + 1]
+end
+
+return Wire