From 9676364c1fe5fe5eae69c55e7d7a45392decfb2d Mon Sep 17 00:00:00 2001
From: Jude Melton-Houghton <jwmhjwmh@gmail.com>
Date: Sun, 9 Oct 2022 10:50:26 -0400
Subject: Optimize lighting calculation (#12797)

---
 src/nodedef.h | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

(limited to 'src/nodedef.h')

diff --git a/src/nodedef.h b/src/nodedef.h
index 8f0d0e9e8..044fdd8b2 100644
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -505,10 +505,13 @@ struct ContentFeatures
 			liquid_alternative_source_id == f.liquid_alternative_source_id;
 	}
 
-	bool lightingEquivalent(const ContentFeatures &other) const {
-		return light_propagates == other.light_propagates
-				&& sunlight_propagates == other.sunlight_propagates
-				&& light_source == other.light_source;
+	ContentLightingFlags getLightingFlags() const {
+		ContentLightingFlags flags;
+		flags.has_light = param_type == CPT_LIGHT;
+		flags.light_propagates = light_propagates;
+		flags.sunlight_propagates = sunlight_propagates;
+		flags.light_source = light_source;
+		return flags;
 	}
 
 	int getGroup(const std::string &group) const
@@ -580,6 +583,15 @@ public:
 		return get(n.getContent());
 	}
 
+	inline ContentLightingFlags getLightingFlags(content_t c) const {
+		// No bound check is necessary, since the array's length is CONTENT_MAX + 1.
+		return m_content_lighting_flag_cache[c];
+	}
+
+	inline ContentLightingFlags getLightingFlags(const MapNode &n) const {
+		return getLightingFlags(n.getContent());
+	}
+
 	/*!
 	 * Returns the node properties for a node name.
 	 * @param name name of a node
@@ -826,6 +838,11 @@ private:
 	 * Even constant NodeDefManager instances can register listeners.
 	 */
 	mutable std::vector<NodeResolver *> m_pending_resolve_callbacks;
+
+	/*!
+	 * Fast cache of content lighting flags.
+	 */
+	ContentLightingFlags m_content_lighting_flag_cache[CONTENT_MAX + 1L];
 };
 
 NodeDefManager *createNodeDefManager();
-- 
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