From 5a03b1f5f928e30cb650f9d16bc4fbb866275405 Mon Sep 17 00:00:00 2001
From: Lars Hofhansl <larsh@apache.org>
Date: Sun, 3 Dec 2017 17:51:58 -0800
Subject: [PATCH] Optionally extend the active object in a players camera
 direction.

See #6667

By setting active_object_send_range_blocks > active_block_range a server admin
can allow clients to retrieve active objects futher out from the player at
relatively low cost to the server
(only objects in the players' view cone are considered).
---
 src/serverenvironment.cpp | 62 +++++++++++++++++++++++++++++++--------
 src/serverenvironment.h   |  6 ++--
 2 files changed, 53 insertions(+), 15 deletions(-)

diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp
index 1ac1ac1ba..92159a469 100644
--- a/src/serverenvironment.cpp
+++ b/src/serverenvironment.cpp
@@ -292,8 +292,27 @@ void fillRadiusBlock(v3s16 p0, s16 r, std::set<v3s16> &list)
 			}
 }
 
-void ActiveBlockList::update(std::vector<v3s16> &active_positions,
-	s16 radius,
+void fillViewConeBlock(v3s16 p0,
+	const s16 r,
+	const v3f camera_pos,
+	const v3f camera_dir,
+	const float camera_fov,
+	std::set<v3s16> &list)
+{
+	v3s16 p;
+	const s16 r_nodes = r * BS * MAP_BLOCKSIZE;
+	for (p.X = p0.X - r; p.X <= p0.X+r; p.X++)
+	for (p.Y = p0.Y - r; p.Y <= p0.Y+r; p.Y++)
+	for (p.Z = p0.Z - r; p.Z <= p0.Z+r; p.Z++) {
+		if (isBlockInSight(p, camera_pos, camera_dir, camera_fov, r_nodes)) {
+			list.insert(p);
+		}
+	}
+}
+
+void ActiveBlockList::update(std::vector<PlayerSAO*> &active_players,
+	s16 active_block_range,
+	s16 active_object_range,
 	std::set<v3s16> &blocks_removed,
 	std::set<v3s16> &blocks_added)
 {
@@ -301,8 +320,25 @@ void ActiveBlockList::update(std::vector<v3s16> &active_positions,
 		Create the new list
 	*/
 	std::set<v3s16> newlist = m_forceloaded_list;
-	for (const v3s16 &active_position : active_positions) {
-		fillRadiusBlock(active_position, radius, newlist);
+	m_abm_list = m_forceloaded_list;
+	for (const PlayerSAO *playersao : active_players) {
+		v3s16 pos = getNodeBlockPos(floatToInt(playersao->getBasePosition(), BS));
+		fillRadiusBlock(pos, active_block_range, m_abm_list);
+		fillRadiusBlock(pos, active_block_range, newlist);
+
+		s16 player_ao_range = std::min(active_object_range, playersao->getWantedRange());
+		// only do this if this would add blocks
+		if (player_ao_range > active_block_range) {
+			v3f camera_dir = v3f(0,0,1);
+			camera_dir.rotateYZBy(playersao->getPitch());
+			camera_dir.rotateXZBy(playersao->getYaw());
+			fillViewConeBlock(pos,
+				player_ao_range,
+				playersao->getEyePosition(),
+				camera_dir,
+				playersao->getFov(),
+				newlist);
+		}
 	}
 
 	/*
@@ -873,10 +909,6 @@ void ServerEnvironment::activateBlock(MapBlock *block, u32 additional_dtime)
 					elapsed_timer.position));
 		}
 	}
-
-	/* Handle ActiveBlockModifiers */
-	ABMHandler abmhandler(m_abms, dtime_s, this, false);
-	abmhandler.apply(block);
 }
 
 void ServerEnvironment::addActiveBlockModifier(ActiveBlockModifier *abm)
@@ -1140,7 +1172,7 @@ void ServerEnvironment::step(float dtime)
 		/*
 			Get player block positions
 		*/
-		std::vector<v3s16> players_blockpos;
+		std::vector<PlayerSAO*> players;
 		for (RemotePlayer *player: m_players) {
 			// Ignore disconnected players
 			if (player->getPeerId() == PEER_ID_INEXISTENT)
@@ -1149,18 +1181,21 @@ void ServerEnvironment::step(float dtime)
 			PlayerSAO *playersao = player->getPlayerSAO();
 			assert(playersao);
 
-			players_blockpos.push_back(
-				getNodeBlockPos(floatToInt(playersao->getBasePosition(), BS)));
+			players.push_back(playersao);
 		}
 
 		/*
 			Update list of active blocks, collecting changes
 		*/
+		// use active_object_send_range_blocks since that is max distance
+		// for active objects sent the client anyway
+		static thread_local const s16 active_object_range =
+				g_settings->getS16("active_object_send_range_blocks");
 		static thread_local const s16 active_block_range =
 				g_settings->getS16("active_block_range");
 		std::set<v3s16> blocks_removed;
 		std::set<v3s16> blocks_added;
-		m_active_blocks.update(players_blockpos, active_block_range,
+		m_active_blocks.update(players, active_block_range, active_object_range,
 			blocks_removed, blocks_added);
 
 		/*
@@ -1187,6 +1222,7 @@ void ServerEnvironment::step(float dtime)
 			MapBlock *block = m_map->getBlockOrEmerge(p);
 			if (!block) {
 				m_active_blocks.m_list.erase(p);
+				m_active_blocks.m_abm_list.erase(p);
 				continue;
 			}
 
@@ -1248,7 +1284,7 @@ void ServerEnvironment::step(float dtime)
 			// Initialize handling of ActiveBlockModifiers
 			ABMHandler abmhandler(m_abms, m_cache_abm_interval, this, true);
 
-			for (const v3s16 &p : m_active_blocks.m_list) {
+			for (const v3s16 &p : m_active_blocks.m_abm_list) {
 				MapBlock *block = m_map->getBlockNoCreateNoEx(p);
 				if (!block)
 					continue;
diff --git a/src/serverenvironment.h b/src/serverenvironment.h
index b8a35f7fd..cb813155d 100644
--- a/src/serverenvironment.h
+++ b/src/serverenvironment.h
@@ -154,8 +154,9 @@ private:
 class ActiveBlockList
 {
 public:
-	void update(std::vector<v3s16> &active_positions,
-		s16 radius,
+	void update(std::vector<PlayerSAO*> &active_players,
+		s16 active_block_range,
+		s16 active_object_range,
 		std::set<v3s16> &blocks_removed,
 		std::set<v3s16> &blocks_added);
 
@@ -168,6 +169,7 @@ public:
 	}
 
 	std::set<v3s16> m_list;
+	std::set<v3s16> m_abm_list;
 	std::set<v3s16> m_forceloaded_list;
 
 private: