implement automatic Moreblocks rotation

Slabs and stairs are now properly rotated again as if they are when
Moreblocks is not used. The rotation functionality was derived from the
original stairs mod that comes with Minetest Game.

README.md

-Changes smaller things that are issues for either [Minetest](https://github.com/minetest/minetest) or [Minetest Game](https://github.com/minetest/minetest_game) that are technically fixable but won’t be fixed due to several non-technical reasons.
+Changes smaller things that are issues for either [Minetest](https://github.com/minetest/minetest), [Minetest Game](https://github.com/minetest/minetest_game), and some well-known mods that are technically fixable but won’t be fixed due to several non-technical reasons.
 
 ## Configuration
 
@@ -12,7 +12,7 @@ The configurations can be set in the global `minetest.conf` file as well as in a
 
 * setting: `redef_3d_ladders = true`
 * disable: set to `false`
-* fixes: [2423]
+* fixes: [mtg2423]
 * default: no 3D ladders
 
 Redefining the 2D ladders so that they use a 3D model. No new textures are needed since he normal textures are used. Only works properly if using the 16x16 default textures or texture packs that use the same size and shape for the ladders.
@@ -23,7 +23,7 @@ Redefining the 2D ladders so that they use a 3D model. No new textures are neede
 
 * setting: `redef_stack_max = 100`
 * disable: set to 0
-* fixes: [1843], [5730], [1724], [394]
+* fixes: [mtg1843], [mtg5730], [mtg1724], [mt394]
 * default: stack size at 99
 
 It changes the maximum stack size of all registered things whose stack size is 99 to the given `redef_stack_max` value. Unfortunately the maximum stack size of 99 is hardcoded in some places and can’t be changed using a mod.
@@ -34,7 +34,7 @@ It changes the maximum stack size of all registered things whose stack size is 9
 
 * setting: `redef_grass_box_height = 2`
 * disable: set to 0
-* fixes: [1980]
+* fixes: [mtg1980]
 * default: various heights for grass selection boxes
 
 Make grass selection box x/16 high for easy building or punching through regardless of actual height of the box.
@@ -45,19 +45,29 @@ Make grass selection box x/16 high for easy building or punching through regardl
 
 * setting: `redef_aligned_textures = true`
 * disable: set to `false`
-* fixes: [2287], [1931], [5222]
+* fixes: [mtg2287], [mtg1931], [mt5222]
 * default: textures not aligned for most relevant nodes
 
 This fixes the texture orientation of stairs and slabs regardless of how they were defined to achieve a clean look. This redefinition also world-alignes moreblocks nodes that are nodeboxes (world-alignment of textures only works on nodeboxes).
 
-[2423]: https://github.com/minetest/minetest_game/issues/2423
-[1843]: https://github.com/minetest/minetest/pull/1843
-[5730]: https://github.com/minetest/minetest/issues/5730
-[1724]: https://github.com/minetest/minetest_game/issues/1724
-[394]: https://github.com/minetest/minetest/issues/394
-[1980]: https://github.com/minetest/minetest_game/issues/1980
-[5214]: https://github.com/minetest/minetest/issues/5214
-[4050]: https://github.com/minetest/minetest/issues/4050
-[2287]: https://github.com/minetest/minetest_game/issues/2287
-[1931]: https://github.com/minetest/minetest_game/issues/1931
-[5222]: https://github.com/minetest/minetest/issues/5222
+### Moreblocks Rotation
+
+![Result](screenshots/redef_moreblocks_rotation.png)
+
+* setting: `redef_moreblocks_rotation = true`
+* disable: set to `false`
+* fixes: [moreblocks138]
+* default: slabs and stairs do not align properly on placement
+
+Moreblocks re-implements all stairs and slabs for unknown reason and thus breaking their placement and auto-rotation. By enabling this, the original functionality is replicated.
+
+[mtg2423]: https://github.com/minetest/minetest_game/issues/2423
+[mtg1843]: https://github.com/minetest/minetest/pull/1843
+[mtg5730]: https://github.com/minetest/minetest/issues/5730
+[mtg1724]: https://github.com/minetest/minetest_game/issues/1724
+[mt394]: https://github.com/minetest/minetest/issues/394
+[mtg1980]: https://github.com/minetest/minetest_game/issues/1980
+[mtg2287]: https://github.com/minetest/minetest_game/issues/2287
+[mtg1931]: https://github.com/minetest/minetest_game/issues/1931
+[mt5222]: https://github.com/minetest/minetest/issues/5222
+[moreblocks138]: https://github.com/minetest-mods/moreblocks/issues/138

init.lua

@@ -28,7 +28,8 @@ minetest.register_on_mods_loaded(function()
         ['3D Ladders'] = minetest.is_yes(g('3d_ladders', true)),
         ['Maximum Stack Size'] = tonumber(g('stack_max', 100)) >= 1,
         ['Grass Box Height'] = tonumber(g('grass_box_height', 2)) >= 1,
-        ['Aligned Textures'] = minetest.is_yes(g('aligned_textures', true))
+        ['Aligned Textures'] = minetest.is_yes(g('aligned_textures', true)),
+        ['Moreblocks Rotation'] = minetest.is_yes(g('moreblocks_rotation',true))
     }
 
     for name,use in pairs(redefinitions) do

redefinitions/moreblocks_rotation.lua

+local override_item = minetest.override_item
+local pointed_thing_to_face_pos = minetest.pointed_thing_to_face_pos
+local dir_to_facedir = minetest.dir_to_facedir
+local is_creative_enabled = minetest.is_creative_enabled
+local item_place_node = minetest.item_place_node
+
+local stairs = {}
+local slabs = {}
+
+
+-- Correct stairs placement
+--
+-- Derived from the original stairs on_place function of Minetest Game.
+--
+-- @param itemstack An itemstack according to Minetest API
+-- @param placer A placer object according to Minetest API
+-- @param pointed_thing A pointed_thing according to Minetest API
+-- @return mixed itemstack and position according to Minetest API
+local properly_rotate = function (itemstack, placer, pointed_thing)
+    local under = pointed_thing.under
+    local above = pointed_thing.above
+    local param2 = 0
+
+    if placer then
+        local placer_pos = placer:get_pos()
+        local finepos = pointed_thing_to_face_pos(placer, pointed_thing)
+        local fpos = finepos.y % 1
+
+        local under_above = under.y - 1 == above.y
+        local fpos_perimeter = (fpos > 0 and fpos < 0.5)
+        local fpos_limit = (fpos < -0.5 and fpos > -0.999999999)
+
+        if placer_pos then
+            param2 = dir_to_facedir(vector.subtract(above, placer_pos))
+        end
+
+        if under_above or fpos_perimeter or fpos_limit then
+            param2 = param2 + 20
+            if param2 == 21 then
+                param2 = 23
+            elseif param2 == 23 then
+                param2 = 21
+            end
+        end
+    end
+
+    return minetest.item_place(itemstack, placer, pointed_thing, param2)
+end
+
+
+-- Correct slabs placement
+--
+-- Derived from the original stairs on_place function of Minetest Game.
+--
+-- @param itemstack An itemstack according to Minetest API
+-- @param placer A placer object according to Minetest API
+-- @param pointed_thing A pointed_thing according to Minetest API
+-- @return mixed itemstack and position according to Minetest API
+local on_place_slabs = function (itemstack, placer, pointed_thing)
+    local under = minetest.get_node(pointed_thing.under)
+    local wield_item = itemstack:get_name()
+    local player_name = placer and placer:get_player_name() or ''
+
+    -- Special behavior if placed on a slab
+    if under and under.name:find(':slab_') then
+        local pt_above = pointed_thing.above
+        local pt_under = pointed_thing.under
+        local fdir = dir_to_facedir(vector.subtract(pt_above, pt_under), true)
+        local p2 = under.param2
+
+        -- Slab placement based on upside-down slabs or below slabs
+        --
+        --     ┌────────┐
+        --     │        │
+        --     ┢━━━━━━━━┪    <-- Slab A (bottom half of the node seen sideways)
+        --     ┃        ┃
+        -- ┈┈┈┈┣━━━━━━━━┫┈┈┈┈
+        --     ┃        ┃
+        --     ┡━━━━━━━━┩    <-- Slab B (top half of the node, seen sideways)
+        --     │        │
+        --     └────────┘
+        --
+        -- Slabs A and B are rotated according slab B or A on placement so that
+        -- slabs placed on regular slabs from below automatically become
+        -- upside-down slabs and slabs placed on top of upside-down slabs are
+        -- not rotated into the same position.
+        if p2 >= 20 and fdir == 8 then p2 = p2 - 20 end -- Slab A rotation
+        if p2 <= 3 and fdir == 4 then p2 = p2 + 20 end  -- Slab B rotation
+
+        -- Place node usind the calculated rotation
+        item_place_node(ItemStack(wield_item), placer, pointed_thing, p2)
+
+        -- Remove one item if not in creative and return the itemstack
+        if not is_creative_enabled(player_name) then itemstack:take_item() end
+        return itemstack
+    end
+
+    -- When not placed on a slab just properly rotate the slab
+    return properly_rotate(itemstack, placer, pointed_thing)
+end
+
+
+
+-- Determine all stairs and slabs and put them into the respective tables.
+for name,definition in pairs(minetest.registered_nodes) do
+    local from_moreblocks = definition.mod_origin == 'moreblocks'
+    local stair = definition.groups.stair
+    local slab = string.match(name, ':slab_') ~= nil
+
+    if stair and from_moreblocks then table.insert(stairs, name) end
+    if slab and from_moreblocks then table.insert(slabs, name) end
+end
+
+
+-- Iterate over all stairs and override the broken on_place function.
+for _,name in pairs(stairs) do
+    override_item(name, {
+        on_place = function (itemstack, placer, pointed_thing)
+            if pointed_thing.type ~= "node" then return itemstack end
+            return properly_rotate(itemstack, placer, pointed_thing)
+        end
+    })
+end
+
+
+-- Iterate over all slabs and override the broken on_place function.
+for _,name in pairs(slabs) do
+    override_item(name, {
+        on_place = function (itemstack, placer, pointed_thing)
+            return on_place_slabs(itemstack, placer, pointed_thing)
+        end
+    })
+end

[Dirk]

This was changed in f78340a2 to also use string-based detection because groups seem to be unreliable for properly detecting all stairs.

[Dirk]

Clicked here

[Dirk]

Clicked here

[Dirk]

Clicked here

[Dirk]

Clicked here