First commit

1 files changed, 156 insertions, 0 deletions

diff --git a/display_lib/init.lua b/display_lib/init.lua
new file mode 100644
index 0000000..eaddfd3
--- /dev/null
+++ b/display_lib/init.lua
@@ -0,0 +1,156 @@
+-- Display lib mod by P.Y. Rollo
+--
+-- License: WTFPL
+
+display_lib = {}
+
+-- Miscelaneous values depending on wallmounted param2
+local wallmounted_values = {
+	[0]={dx=0,  dz=0,  lx=0, lz=0,  yaw=0,          rotate=0}, -- Should never be used
+		{dx=1,  dz=0,  lx=0, lz=0,  yaw=0,          rotate=1}, -- Should never be used 
+		{dx=1,  dz=0,  lx=0, lz=-1, yaw=-math.pi/2, rotate=4},
+		{dx=-1, dz=0,  lx=0, lz=1,  yaw=math.pi/2,  rotate=5},
+		{dx=0,  dz=1,  lx=1, lz=0,  yaw=0,          rotate=3},
+		{dx=0,  dz=-1, lx=-1, lz=0, yaw=math.pi,    rotate=2}
+}
+
+--- Gets the display entities attached with a node. Removes extra ones
+local function get_entities(pos)
+	local objrefs = {}
+	local ndef = minetest.registered_nodes[minetest.get_node(pos).name]
+	if ndef and ndef.display_entities then
+		for _, objref in ipairs(minetest.get_objects_inside_radius(pos, 0.5)) do
+			local entity = objref:get_luaentity()
+		    if entity and ndef.display_entities[entity.name] then
+				if objrefs[entity.name] then
+				    objref:remove()
+				else
+					objrefs[entity.name] = objref
+				end
+		    end
+		end
+	end
+	return objrefs
+end
+
+local function clip_pos_prop(posprop)
+	if posprop then
+		return math.max(-0.5, math.min(0.5, posprop))
+	else
+		return 0
+	end
+end
+
+--- (Create and) place display entities according to the node orientation
+local function place_entities(pos)
+	local node = minetest.get_node(pos)
+	local ndef = minetest.registered_nodes[node.name]
+	local values = wallmounted_values[node.param2]
+	local objrefs = get_entities(pos)
+
+	if ndef and ndef.display_entities then
+		for entity_name, props in pairs(ndef.display_entities) do
+			local depth = clip_pos_prop(props.depth)
+			local top = clip_pos_prop(props.top)
+			local left = clip_pos_prop(props.left)
+			
+			if not objrefs[entity_name] then
+				objrefs[entity_name] = minetest.add_entity(pos, entity_name)
+			end
+
+			objrefs[entity_name]:setpos({
+				x = pos.x - values.dx * depth + values.lx * left,
+				y = pos.y + top,
+				z = pos.z - values.dz * depth + values.lz * left})
+
+			objrefs[entity_name]:setyaw(values.yaw)
+		end
+	end
+	return objrefs
+end
+
+--- Call on_display_update callback of a node for one of its display entities
+local function call_node_on_display_update(pos, objref)
+	local ndef = minetest.registered_nodes[minetest.get_node(pos).name]
+	local entity = objref:get_luaentity()
+	if ndef and ndef.display_entities and entity and ndef.display_entities[entity.name] then
+		ndef.display_entities[entity.name].on_display_update(pos, objref)
+	end	
+end
+
+--- Force entity update
+function display_lib.update_entities(pos)
+	local objrefs = place_entities(pos)
+	for _, objref in pairs(objrefs) do
+		call_node_on_display_update(pos, objref)
+    end
+end
+
+--- On_activate callback for display_lib entities. Calls on_display_update callbacks 
+--- of corresponding node for each entity.
+function display_lib.on_activate(entity, staticdata)
+	if entity then
+		call_node_on_display_update(entity.object:getpos(), entity.object)
+	end
+end
+
+--- On_place callback for display_lib items. Does nothing more than preventing item
+--- from being placed on ceiling or ground 
+function display_lib.on_place(itemstack, placer, pointed_thing)
+	local above = pointed_thing.above
+	local under = pointed_thing.under
+	local dir = {x = under.x - above.x,
+				 y = under.y - above.y,
+				 z = under.z - above.z}
+	local wdir = minetest.dir_to_wallmounted(dir)
+
+	if wdir == 0 or wdir == 1 then
+		dir = placer:get_look_dir()
+		dir.y = 0
+		wdir = minetest.dir_to_wallmounted(dir)
+	end
+	return minetest.item_place(itemstack, placer, pointed_thing, wdir) 
+end
+
+--- On_construct callback for display_lib items. Creates entities and update them.
+function display_lib.on_construct(pos)
+	display_lib.update_entities(pos)
+end
+
+--- On_destruct callback for display_lib items. Removes entities.
+function display_lib.on_destruct(pos)
+	local objrefs = get_entities(pos)
+	
+	for _, objref in pairs(objrefs) do 
+		objref:remove()
+	end
+end
+
+
+-- On_rotate (screwdriver) callback for display_lib items. Prevents axis rotation and reorients entities.
+function display_lib.on_rotate(pos, node, user, mode, new_param2)
+	if mode ~= screwdriver.ROTATE_FACE then return false end
+
+	if wallmounted_values[node.param2] then
+		minetest.swap_node(pos, {name = node.name, param1 = node.param1, param2 = wallmounted_values[node.param2].rotate})
+		place_entities(pos)
+		return true
+	else
+		return false
+	end
+end
+
+--- Creates display entity with some fields and the on_activate callback
+function display_lib.register_display_entity(entity_name)
+	if not minetest.registered_entity then
+		minetest.register_entity(':'..entity_name, {
+			collisionbox = { 0, 0, 0, 0, 0, 0 },
+			visual = "upright_sprite",
+			textures = {},
+			on_activate = display_lib.on_activate,
+		})
+	end
+end
+
+
+