Add rotatable registry

- Add register_rotatable
  Registers a node that can be rotated.
- Add fix_rotatable_facedir
  Looks up equivalent facedir value from
  loopup array specified when registering.
- Replace rotate_node with rotate_facedir
  Rotates a facedir value instead of a node in-world.
- Add calculate_rotating_state
  To separate state-creation into its own function,
  and to fix an issue where HUD wouldn't update.
- Add nodecore_filtered_lookup
  Mimics NodeCore's rotation filtering to create
  a lookup table based on a passed-in function.
- Register lenses, prisms and panels

init.lua

@@ -1,28 +1,61 @@
-local minetest, vector, nodecore, include
-    = minetest, vector, nodecore, include
+local ipairs, minetest, vector, nodecore, include
+    = ipairs, minetest, vector, nodecore, include
 
 local hud     = include("hud")
 local rotate  = include("rotate")
 local utility = include("utility")
 
 -- TODO: Add crosshair indicators for rotating around edges.
--- TODO: Register only the nodes that should be rotatable.
--- TODO: Replace `on_rightclick` of intended nodes.
+-- TODO: Replace `on_rightclick` of intended nodes?
+-- TODO: Allow right-clicking while holding sneak with an empty hand to invert rotation.
 -- TODO: Add some more comments.
 
 -- Distance at which we want to rotate by "pushing" on an edge.
 local EDGE_DISTANCE = 1.5 / 16 -- 1.5 texels (at 16² texture resolution)
 
+-- Contains a per-player state that holds information, created by a raycast
+-- done in `playerstep`, about the node this player might rotate. This is used
+-- to decide what to do when a rightclick occurs and to update the their HUD.
 local rotating_state = {}
 
-nodecore.register_playerstep({
-    label = "extended rotating update",
-    action = function(player, player_data)
-        local name  = player:get_player_name()
-        local state = {}; rotating_state[name] = state
+-- Register rotatable nodes.
+do
+    local function nodecore_filtered_lookup(eq_func)
+        local lookup = {}
+        for i = 0, 23 do
+            local facedir = nodecore.facedirs[i]
+            for j = 1, #lookup do
+                local other = nodecore.facedirs[lookup[j]]
+                if eq_func(facedir, other) then lookup[i] = j; break end
+            end
+            lookup[i] = lookup[i] or i
+        end
+        return lookup
+    end
+
+    local LENS_FILTERED_LOOKUP = nodecore_filtered_lookup(
+        function(a, b) return vector.equals(a.f, b.f) end)
+    local PRISM_FILTERED_LOOKUP = nodecore_filtered_lookup(
+        function(a, b) return vector.equals(a.f, b.r) and vector.equals(a.r, b.f) end)
+    local PANEL_FILTERED_LOOKUP = nodecore_filtered_lookup(
+        function(a, b) return vector.equals(a.f, b.r) and vector.equals(a.r, b.f) end)
 
-        local pointed_thing = player_data.raycast()
-        if (not pointed_thing) or pointed_thing.type ~= "node" then return nil end
+    for _, lens_state in ipairs({ "", "_on", "_glow", "_glow_start" }) do
+        rotate.register_rotatable("nc_optics:lens" .. lens_state, LENS_FILTERED_LOOKUP) end
+    for _, prism_state in ipairs({ "", "_on", "_gated" }) do
+        rotate.register_rotatable("nc_optics:prism" .. prism_state, PRISM_FILTERED_LOOKUP) end
+
+    rotate.register_rotatable("nc_doors:panel_plank" , PANEL_FILTERED_LOOKUP)
+    rotate.register_rotatable("nc_doors:panel_cobble", PANEL_FILTERED_LOOKUP)
+end
+
+-- Calculates the state for the specified `player` and player `data`.
+-- This state contains information about how the player would rotate a block.
+local function calculate_rotating_state(player, data)
+    local state = {}
+
+    local pointed_thing = data.raycast()
+    if (not pointed_thing) or pointed_thing.type ~= "node" then return end
 
     state.pos  = pointed_thing.under
     state.node = minetest.get_node(state.pos)
@@ -32,16 +65,31 @@ nodecore.register_playerstep({
     state.face = pointed_thing.above - pointed_thing.under
 
     local edge, distance = utility.find_closest_edge(state.node, pointed_thing)
-        if edge and distance > EDGE_DISTANCE then
+    -- FIXME: Something in `find_closest_edge` is causing an unexpected edge to be returned, hence the additional check.
+    if edge and distance <= EDGE_DISTANCE and state.face:multiply(edge):length() ~= 0 then
+        state.axis = state.face:cross(edge):normalize()
+        state.mode = "edge"
+    else
         state.axis = state.face
         state.mode = "face"
-        else
-            state.axis = state.face:cross(edge):normalize():round()
-            state.mode = "edge"
     end
 
     state.invert = player:get_player_control().sneak
-        hud.update_player_hud(player, state)
+
+    local degrees = state.invert and 90 or -90
+    state.facedir = rotate.rotate_facedir(state.node.param2, state.axis, degrees)
+    state.facedir = rotate.fix_rotatable_facedir(state.node, state.facedir)
+    state.success = state.facedir and state.facedir ~= state.node.param2
+
+    return state
+end
+
+nodecore.register_playerstep({
+    label = "extended rotating update",
+    action = function(player, data)
+        local name = player:get_player_name()
+        rotating_state[name] = calculate_rotating_state(player, data)
+        hud.update_player_hud(player, rotating_state[name])
     end,
 })
 
@@ -50,7 +98,6 @@ minetest.register_on_leaveplayer(function(player)
     rotating_state[name] = nil
 end)
 
-
 minetest.register_on_punchnode(function(pos, node, puncher, pointed_thing)
     if not minetest.is_player(puncher) then return end
     local name  = puncher:get_player_name()
@@ -61,6 +108,8 @@ minetest.register_on_punchnode(function(pos, node, puncher, pointed_thing)
     if not vector.equals(pos, state.pos) then return end
     if node.name ~= state.node.name or node.param2 ~= state.node.param2 then return end
 
-    local degrees = state.invert and 90 or -90
-    rotate.rotate_node(state.pos, state.node, state.axis, degrees)
+    -- Only continue if the node can actually be sucessfully rotated.
+    if not state.success then return end
+
+    minetest.swap_node(pos, nodecore.underride({ param2 = state.facedir }, node))
 end)

mod.conf

@@ -2,4 +2,4 @@ name = nc_extended_rotating
 title = NodeCore Extended Rotating
 author = copygirl
 description = Rotate optics and doors from NodeCore with ease.
-depends = nc_api_all
+depends = nc_api_all, nc_optics, nc_doors

rotate.lua

@@ -7,6 +7,8 @@ local minetest, vector
 
 local rotate = {}
 
+local rotatable_registry = {}
+
 -- Axis lookup table based on how Minetest's `facedir` operates.
 local AXIS_LOOKUP = {
     vector.new( 0,  1,  0), -- +Y
@@ -50,14 +52,54 @@ for up_index, up in ipairs(AXIS_LOOKUP) do
     end
 end
 
+local function register_rotatable(name, facedir_lookup)
+    local def = minetest.registered_nodes[name]
+    if not def then error("Unknown node '" .. name .. "'") end
+    if def.paramtype2 ~= "facedir" then error("Node '" .. name .. "' must be 'facedir'") end
+    rotatable_registry[name] = { lookup = facedir_lookup }
+end
+rotate.register_rotatable = register_rotatable
+
 -- Returns whether the specified `node` is rotatable by this mod.
 local function is_rotatable(node)
-    local name = node and node.name
-    local def  = minetest.registered_nodes[name]
-    return def and def.paramtype2 == "facedir"
+    local name = node and node.name or ""
+    return not not rotatable_registry[name]
 end
 rotate.is_rotatable = is_rotatable
 
+-- Fixes facedir for the specified `node` when rotated to `facedir`.
+-- * Returns `nil` if the node can't rotate this way.
+-- * Returns `facedir` when the node can rotate this way.
+-- * Returns another facedir when the node should rotate another equivalent way.
+local function fix_rotatable_facedir(node, facedir)
+    local name  = node and node.name or ""
+    local entry = rotatable_registry[name]
+    if not entry then return nil end
+    if not entry.lookup then return facedir end
+    return entry.lookup[facedir]
+end
+rotate.fix_rotatable_facedir = fix_rotatable_facedir
+
+-- Returns the specified `facedir` rotated around `axis` by `degrees` counter-clickwise.
+local function rotate_facedir(facedir, axis, degrees)
+    if degrees % 90 ~= 0 then error("degrees must be divisible by 90") end
+    if axis_vector_to_index(axis) == nil then error("axis " .. tostring(axis) .. " is not an axis vector") end
+
+    local up   = AXIS_LOOKUP[1 + math_floor(facedir / 4)]
+    local back = minetest.facedir_to_dir(facedir)
+
+    up   = up  :rotate_around_axis(axis, math_rad(degrees)):round()
+    back = back:rotate_around_axis(axis, math_rad(degrees)):round()
+
+    local up_index   = axis_vector_to_index(up)
+    local back_index = axis_vector_to_index(back)
+
+    return FACEDIR_LOOKUP[up_index][back_index]
+end
+rotate.rotate_facedir = rotate_facedir
+
+-- Rotates the specified default orientation `{ min, max }` box to
+-- one matching Minetest's rotation algorithm pointing to `facedir`.
 local function rotate_box_by_facedir(box, facedir)
     if facedir == 0 then return end
 
@@ -83,24 +125,4 @@ local function rotate_box_by_facedir(box, facedir)
 end
 rotate.rotate_box_by_facedir = rotate_box_by_facedir
 
--- Rotates `node` at the specified `pos` around `axis` by `degrees` counter-clockwise.
-local function rotate_node(pos, node, axis, degrees)
-    if degrees % 90 ~= 0 then error("degrees must be divisible by 90") end
-    if axis_vector_to_index(axis) == nil then error("axis must be an axis vector") end
-    if not is_rotatable(node) then error("node is not rotatable") end
-
-    local up   = AXIS_LOOKUP[1 + math_floor(node.param2 / 4)]
-    local back = minetest.facedir_to_dir(node.param2)
-
-    up   = up  :rotate_around_axis(axis, math_rad(degrees)):round()
-    back = back:rotate_around_axis(axis, math_rad(degrees)):round()
-
-    local up_index   = axis_vector_to_index(up)
-    local back_index = axis_vector_to_index(back)
-
-    node.param2 = FACEDIR_LOOKUP[up_index][back_index]
-    minetest.set_node(pos, node)
-end
-rotate.rotate_node = rotate_node
-
 return rotate