From 3aefa5d3ceaaa9299f42cc10921dec65fa53c5e0 Mon Sep 17 00:00:00 2001
From: paramat <mat.gregory@virginmedia.com>
Date: Thu, 15 Sep 2016 22:40:19 +0100
Subject: [PATCH] Register.lua: Throw error if node 'light_source' >
core.LIGHT_MAX
Add 'core.LIGHT_MAX = 14' to builtin/game/constants.lua with the intention
to replace misplaced 'default.LIGHT_MAX = 14' in Minetest Game.
Add comment in light.h requiring the constant be changed in both places.
Add lighting bug warning to note in lua_api.txt.
There are hundreds of mod uses of 15 which causes a lighting bug.
---
builtin/game/constants.lua | 5 +++++
builtin/game/register.lua | 3 +++
doc/lua_api.txt | 5 ++++-
src/light.h | 6 ++++--
4 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/builtin/game/constants.lua b/builtin/game/constants.lua
index 56fca9289..50c515b24 100644
--- a/builtin/game/constants.lua
+++ b/builtin/game/constants.lua
@@ -19,4 +19,9 @@ core.EMERGE_FROM_DISK = 3
core.EMERGE_GENERATED = 4
-- constants.h
+-- Size of mapblocks in nodes
core.MAP_BLOCKSIZE = 16
+
+-- light.h
+-- Maximum value for node 'light_source' parameter
+core.LIGHT_MAX = 14
diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index 05dc5fef8..d3f6b3df8 100644
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -127,6 +127,9 @@ function core.register_item(name, itemdef)
fixed = {-1/8, -1/2, -1/8, 1/8, 1/2, 1/8},
}
end
+ if itemdef.light_source and itemdef.light_source > core.LIGHT_MAX then
+ error("Unable to register node: 'light_source' exceeds maximum: " .. name)
+ end
setmetatable(itemdef, {__index = core.nodedef_default})
core.registered_nodes[itemdef.name] = itemdef
elseif itemdef.type == "craft" then
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index b6e6520b2..6f69360c8 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -3664,7 +3664,10 @@ Definition tables
^ Don't forget to use "leveled" type nodebox. ]]
liquid_range = 8, -- number of flowing nodes around source (max. 8)
drowning = 0, -- Player will take this amount of damage if no bubbles are left
- light_source = 0, -- Amount of light emitted by node (max. 14)
+ light_source = 0, --[[
+ ^ Amount of light emitted by node.
+ ^ To set the maximum (currently 14), use the value 'minetest.LIGHT_MAX'.
+ ^ A value outside the range 0 to minetest.LIGHT_MAX causes undefined behavior.]]
damage_per_second = 0, -- If player is inside node, this damage is caused
node_box = {type="regular"}, -- See "Node boxes"
connects_to = nodenames, --[[
diff --git a/src/light.h b/src/light.h
index f49be4518..984e6d7c2 100644
--- a/src/light.h
+++ b/src/light.h
@@ -27,8 +27,10 @@ with this program; if not, write to the Free Software Foundation, Inc.,
*/
// This directly sets the range of light.
-// Actually this is not the real maximum, and this is not the
-// brightest. The brightest is LIGHT_SUN.
+// Actually this is not the real maximum, and this is not the brightest, the
+// brightest is LIGHT_SUN.
+// If changed, this constant as defined in builtin/game/constants.lua must
+// also be changed.
#define LIGHT_MAX 14
// Light is stored as 4 bits, thus 15 is the maximum.
// This brightness is reserved for sunlight
--
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