Implement (untested!) manip interface on top of the raw convolutional code

worldeditadditions/init.lua

@@ -10,6 +10,7 @@ worldeditadditions.modpath = minetest.get_modpath("worldeditadditions")
 dofile(worldeditadditions.modpath.."/utils/strings.lua")
 dofile(worldeditadditions.modpath.."/utils/numbers.lua")
 dofile(worldeditadditions.modpath.."/utils/nodes.lua")
+dofile(worldeditadditions.modpath.."/utils/tables.lua")
 
 dofile(worldeditadditions.modpath.."/utils.lua")
 dofile(worldeditadditions.modpath.."/lib/floodfill.lua")

worldeditadditions/lib/convolution/convolution.lua

@@ -4,3 +4,86 @@ dofile(worldeditadditions.modpath.."/lib/conv/kernels.lua")
 dofile(worldeditadditions.modpath.."/lib/conv/kernel_gaussian.lua")
 
 dofile(worldeditadditions.modpath.."/lib/conv/convolve.lua")
+
+--- Creates a new kernel.
+-- Note that the gaussian kernel only allows for creating a square kernel.
+-- arg is only used by the gaussian kernel as the sigma value (default: 2)
+-- @param	name	string	The name of the kernel to create (possible values: box, pascal, gaussian).
+-- @param	width	number	The width of the kernel to create (must be an odd integer).
+-- @param	height	number	The height of the kernel to create (must be an odd integer).
+-- @param	arg		number	The argument to pass when creating the kernel. Currently only used by gaussian kernel as the sigma value.
+function worldeditadditions.get_kernel(name, width, height, arg)
+	if width % 2 ~= 1 then
+		return false, "Error: The width must be an odd integer.";
+	end
+	if height % 2 ~= 1 then
+		return false, "Error: The height must be an odd integer";
+	end
+	
+	if name == "box" then
+		return true, worldeditadditions.conv.kernel_box(width, height)
+	elseif name == "pascal" then
+		return true, worldeditadditions.conv.kernel_pascal(width, height, true)
+	elseif name == "gaussian" then
+		if width ~= height then
+			return false, "Error: When using a gaussian kernel the width and height must be identical."
+		end
+		-- Default to sigma = 2
+		if arg == nil then arg = 2 end
+		local success, result = worldeditadditions.conv.kernel_gaussian(width, arg)
+		return success, result
+	end
+end
+
+
+function worldeditadditions.convolve(pos1, pos2, kernel, kernel_size)
+	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	
+	local manip, area = worldedit.manip_helpers.init(pos1, pos2)
+	local data = manip:get_data()
+	
+	local stats = { added = 0, removed = 0 }
+	
+	local node_id_air = minetest.get_content_id("air")
+	
+	local heightmap = worldeditadditions.make_heightmap(pos1, pos2, manip, area, data)
+	local heightmap_conv = worldeditadditions.shallowcopy(heightmap)
+	
+	local heightmap_size = {}
+	heightmap_size[0] = pos2.z - pos1.z
+	heightmap_size[1] = pos2.x - pos1.x
+	
+	worldeditadditions.conv.convolve(
+		heightmap_conv,
+		heightmap_size,
+		kernel,
+		kernel_size
+	)
+	for z = heightmap_size[0], 0, -1 do
+		for x = heightmap_size[1], 0, -1 do
+			local hi = z*heightmap_size[1] + x
+			local diff = heightmap_conv[hi] - heightmap[hi]
+			
+			
+			-- Lua doesn't have a continue statement :-/
+			if diff ~= 0 then
+				local node_id = data[area:index(pos1.x + x, pos1.y + heightmap[hi], pos1.z + z)]
+				if diff > 0 then
+					stats.added = stats.added + diff
+					for y = pos1.y + heightmap[hi], pos1.y + heightmap_conv[hi], 1 do
+						data[area:index(pos1.x + x, y, pos1.z + z)] = node_id
+					end
+				else
+					stats.removed = stats.removed + math.abs(diff)
+					for y = pos1.y + heightmap_conv[hi], pos1.y + heightmap[hi], 1 do
+						data[area:index(pos1.x + x, y, pos1.z + z)] = node_id_air
+					end
+				end
+			end
+		end
+	end
+	
+	worldedit.manip_helpers.finish(manip, data)
+	
+	return true, stats
+end

worldeditadditions/lib/convolution/kernel_gaussian.lua

@@ -47,5 +47,5 @@ function worldeditadditions.conv.kernel_gaussian(dimension, sigma)
 		kernel[k] = kernel[k] / sum
 	end
 	
-	return kernel
+	return true, kernel
 end

worldeditadditions/utils/nodes.lua

@@ -14,3 +14,69 @@ function worldeditadditions.make_weighted(tbl)
 	end
 	return result, #result
 end
+
+local node_id_air = minetest.get_content_id("air")
+local node_id_ignore = minetest.get_content_id("ignore")
+
+--- Determines whether the given node/content id is an airlike node or not.
+-- @param	id		number	The content/node id to  check.
+-- @return	bool	Whether the given node/content id is an airlike node or not.
+function worldeditadditions.is_airlike(id)
+	--  Do a fast check against air and ignore
+	if id == node_id_air then
+		return true
+	elseif id == node_id_ignore then -- ignore = not loaded yet IIRC (so it could be anything)
+		return false
+	end
+	
+	local name = minetest.get_name_from_content_id(id)
+	-- If the node isn't registered, then it might not be an air node
+	if not minetest.registered_nodes[id] then return false end
+	if minetest.registered_nodes[id].sunlight_propagates == true then
+		return true
+	end
+	-- Check for membership of the airlike group
+	local airlike_value = minetest.get_item_group(name, "airlike")
+	if airlike_value ~= nil and airlike_value > 0 then
+		return true
+	end
+	-- Just in case
+	return false
+end
+
+--- Given a manip object and associates, generates a 2D x/z heightmap.
+-- Note that pos1 and pos2 should have already been pushed through
+-- worldedit.sort_pos(pos1, pos2) before passing them to this function.
+-- @param	pos1	Vector		Position 1 of the region to operate on
+-- @param	pos2	Vector		Position 2 of the region to operate on
+-- @param	manip	VoxelManip	The VoxelManip object.
+-- @param	area	area		The associated area object.
+-- @param	data	table		The associated data object.
+-- @return	table	The ZERO-indexed heightmap data (as 1 single flat array).
+function worldeditadditions.make_heightmap(pos1, pos2, manip, area, data)
+	-- z y x (in reverse for little-endian machines) is the preferred loop order, but that isn't really possible here
+	
+	local heightmap = {}
+	local hi = 0
+	local changes = { updated = 0, skipped_columns = 0 }
+	for z = pos1.z, pos2.z, 1 do
+		for x = pos1.x, pos2.x, 1 do
+			local found_node = false
+			-- Scan each column top to bottom
+			for y = pos2.y, pos1.y, -1 do
+				local i = area:index(x, y, z)
+				if not worldeditadditions.is_airlike(data[i]) then
+					-- It's the first non-airlike node in this column
+					heightmap[hi] = pos1.y - y
+					found_node = true
+					break
+				end
+			end
+			
+			if not found_node then heightmap[hi] = -1 end
+			i = i + 1
+		end
+	end
+	
+	return heightmap
+end

worldeditadditions/utils/tables.lua

@@ -0,0 +1,17 @@
+--- Shallow clones a table.
+-- @source	http://lua-users.org/wiki/CopyTable
+-- @param	orig	table	The table to clone.
+-- @return	table	The cloned table.
+function worldeditadditions.shallowcopy(orig)
+	local orig_type = type(orig)
+	local copy
+	if orig_type == 'table' then
+		copy = {}
+		for orig_key, orig_value in pairs(orig) do
+			copy[orig_key] = orig_value
+		end
+	else -- number, string, boolean, etc
+		copy = orig
+	end
+	return copy
+end