From 2f4037752b023f87ca1f8859a8dce4f833353967 Mon Sep 17 00:00:00 2001
From: HybridDog <3192173+HybridDog@users.noreply.github.com>
Date: Tue, 6 Oct 2020 20:49:46 +0200
Subject: Add minetest.get_artificial_light and minetest.get_natural_light
 (#5680)

Add more detailed light detection functions, a function to get the artificial light (torches) and a function to get the sunlight as seen by the player (you can specify timeofday).

Co-authored-by: rubenwardy <rw@rubenwardy.com>
---
 src/script/lua_api/l_env.cpp | 41 +++++++++++++++++++++++++++++++++++++++++
 src/script/lua_api/l_env.h   |  5 +++++
 2 files changed, 46 insertions(+)

(limited to 'src/script')

diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 138e88ae8..8d50d664d 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -407,6 +407,46 @@ int ModApiEnvMod::l_get_node_light(lua_State *L)
 	return 1;
 }
 
+
+// get_natural_light(pos, timeofday)
+// pos = {x=num, y=num, z=num}
+// timeofday: nil = current time, 0 = night, 0.5 = day
+int ModApiEnvMod::l_get_natural_light(lua_State *L)
+{
+	GET_ENV_PTR;
+
+	v3s16 pos = read_v3s16(L, 1);
+
+	bool is_position_ok;
+	MapNode n = env->getMap().getNode(pos, &is_position_ok);
+	if (!is_position_ok)
+		return 0;
+
+	// If the daylight is 0, nothing needs to be calculated
+	u8 daylight = n.param1 & 0x0f;
+	if (daylight == 0) {
+		lua_pushinteger(L, 0);
+		return 1;
+	}
+
+	u32 time_of_day;
+	if (lua_isnumber(L, 2)) {
+		time_of_day = 24000.0 * lua_tonumber(L, 2);
+		time_of_day %= 24000;
+	} else {
+		time_of_day = env->getTimeOfDay();
+	}
+	u32 dnr = time_to_daynight_ratio(time_of_day, true);
+
+	// If it's the same as the artificial light, the sunlight needs to be
+	// searched for because the value may not emanate from the sun
+	if (daylight == n.param1 >> 4)
+		daylight = env->findSunlight(pos);
+
+	lua_pushinteger(L, dnr * daylight / 1000);
+	return 1;
+}
+
 // place_node(pos, node)
 // pos = {x=num, y=num, z=num}
 int ModApiEnvMod::l_place_node(lua_State *L)
@@ -1358,6 +1398,7 @@ void ModApiEnvMod::Initialize(lua_State *L, int top)
 	API_FCT(get_node);
 	API_FCT(get_node_or_nil);
 	API_FCT(get_node_light);
+	API_FCT(get_natural_light);
 	API_FCT(place_node);
 	API_FCT(dig_node);
 	API_FCT(punch_node);
diff --git a/src/script/lua_api/l_env.h b/src/script/lua_api/l_env.h
index 07d4d2438..7f212b5fc 100644
--- a/src/script/lua_api/l_env.h
+++ b/src/script/lua_api/l_env.h
@@ -56,6 +56,11 @@ private:
 	// timeofday: nil = current time, 0 = night, 0.5 = day
 	static int l_get_node_light(lua_State *L);
 
+	// get_natural_light(pos, timeofday)
+	// pos = {x=num, y=num, z=num}
+	// timeofday: nil = current time, 0 = night, 0.5 = day
+	static int l_get_natural_light(lua_State *L);
+
 	// place_node(pos, node)
 	// pos = {x=num, y=num, z=num}
 	static int l_place_node(lua_State *L);
-- 
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