first commit

README.md

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+Minetest mod to disable drowning, so you can swim and live underwater forever.  
+
+I made this because I hate timers in non-action games.  Air limits are just another form of timer, preventing underwater gameplay from being fun.  Minetest already does underwater a bit better than Minecraft in a few ways (better visual visibility, faster movement, no reduce mining speed) and this change is the last piece of the puzzle to make underwater a potentially enjoyable option.
+
+## License (zlib)
+
+Copyright (c) William Hales (Minisleep, https://halestrom.net)
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.

init.lua

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+--[[
+Drowning logic is implemented in PlayerSAO::step() in src/server/player_sao.cpp.  There is no global flag (like drowningEnable) or value (like maxBreath) that can be changed easily by a user or a lua mod to disable drowning.
+
+The correct way to solve this problem would be to add such configuration options to the game code.  I will try to add this feature and get it merged, but it will take time.  Meanwhile this mod makes it a lot more fun to explore underwater :)
+
+This script edits nodes to disable drowning.  It's less resource intensive and potentially less buggy than some other options (like periodically upping the breath on a player) but perhaps not as effective in certain corner cases.
+]]--
+
+local function make_water_breathable()
+	local num_modified_nodes = 0
+
+	for nodename,nodedef in pairs(minetest.registered_nodes)
+	do
+		--[[
+		The minetest.registered_nodes lua table is a _copy_ of what the game engine sees.	Modifying it does NOT affect actual in-engine gameplay.
+		
+		Instead we have to re-register the node again after editing it, using a special syntax (":" in front of the node name) to tell the engine that we want to overwrite the existing definition.  See https://forum.minetest.net/viewtopic.php?t=4418 (and beware that not all of the answers there work).	
+		]]--
+		if nodedef ~= nil and nodedef.drowning ~= 0
+		then
+			print("nodrown: Disabling drowning on node " .. nodename)
+			nodedef.drowning = 0
+			minetest.register_node(":" .. nodename, nodedef)
+			num_modified_nodes = num_modified_nodes + 1
+		end
+	end
+	
+	print("nodrown: Modified " .. num_modified_nodes .. " nodes")
+end
+
+--[[
+We can't modify nodes when this init.lua is run, because it might run before some other mods register their nodes.
+
+The normal way to fix this is to add the other mods to our mod's dependency list (which forces them to load before us), but then we would need a unique version of the nodrown mod to suit every other mod and mod combination (impossible).
+
+We can't make our node edits during gameplay.  That leads to weird behaviours (water not spreading) and errors like this:
+
+	2023-06-10 21:35:17: ERROR[Server]: Not allowing to place CONTENT_IGNORE while trying to replace "air" at (222,-106,286) (block (13,-7,17))
+
+Luckily minetest.register_on_mods_loaded() seems to save the day.  It's a bit hacky (other mods could potentially use it to register nodes, which takes us back to square one) but it seems to work.
+]]--
+minetest.register_on_mods_loaded(make_water_breathable)

mod.conf

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+name = nodrown
+title = Nodrown
+description = Disables drowning, so you can swim and live underwater forever.
+author = Minisleep
+license = CC0