From 82c94627030b3973584b27afefab9327e55dcc0b Mon Sep 17 00:00:00 2001
From: Roman Chistokhodov <freeslave93@gmail.com>
Date: Mon, 20 Jun 2022 20:59:36 +0300
Subject: [PATCH] Better retreat from danger

---
 dlls/basemonster.h |  1 +
 dlls/monsters.cpp  | 70 ++++++++++++++++++++++++++++++++++++++++++++++
 dlls/schedule.cpp  | 21 +++++++++-----
 3 files changed, 85 insertions(+), 7 deletions(-)

diff --git a/dlls/basemonster.h b/dlls/basemonster.h
index 2b0464259..803190937 100644
--- a/dlls/basemonster.h
+++ b/dlls/basemonster.h
@@ -238,6 +238,7 @@ class CBaseMonster : public CBaseToggle
 
 	bool FindLateralCover(const Vector& vecThreat, const Vector& vecViewOffset);
 	virtual bool FindCover(Vector vecThreat, Vector vecViewOffset, float flMinDist, float flMaxDist);
+	bool FindRetreat(Vector vecThreat, float flMinDist, float flMaxDist);
 	virtual bool FValidateCover(const Vector& vecCoverLocation) { return true; }
 	virtual float CoverRadius() { return 784; } // Default cover radius
 
diff --git a/dlls/monsters.cpp b/dlls/monsters.cpp
index af4809880..0f8ca79b7 100644
--- a/dlls/monsters.cpp
+++ b/dlls/monsters.cpp
@@ -2317,6 +2317,76 @@ bool CBaseMonster::FindCover(Vector vecThreat, Vector vecViewOffset, float flMin
 	return false;
 }
 
+bool CBaseMonster::FindRetreat(Vector vecThreat, float flMinDist, float flMaxDist)
+{
+	int i;
+	int iMyHullIndex;
+	int iMyNode;
+	int iThreatNode;
+	float flDist;
+
+	if (0 == flMaxDist)
+	{
+		// user didn't supply a MaxDist, so work up a crazy one.
+		flMaxDist = 784;
+	}
+
+	if (flMinDist > 0.5 * flMaxDist)
+	{
+#if _DEBUG
+		ALERT(at_console, "FindRetreat MinDist (%.0f) too close to MaxDist (%.0f)\n", flMinDist, flMaxDist);
+#endif
+		flMinDist = 0.5 * flMaxDist;
+	}
+
+	if (0 == WorldGraph.m_fGraphPresent || 0 == WorldGraph.m_fGraphPointersSet)
+	{
+		ALERT(at_aiconsole, "Graph not ready for findretreat!\n");
+		return false;
+	}
+
+	iMyNode = WorldGraph.FindNearestNode(pev->origin, this);
+	iThreatNode = WorldGraph.FindNearestNode(vecThreat, this);
+	iMyHullIndex = WorldGraph.HullIndex(this);
+
+	if (iMyNode == NO_NODE)
+	{
+		ALERT(at_aiconsole, "FindRetreat() - %s has no nearest node!\n", STRING(pev->classname));
+		return false;
+	}
+	if (iThreatNode == NO_NODE)
+	{
+		// ALERT ( at_aiconsole, "FindRetreat() - Threat has no nearest node!\n" );
+		iThreatNode = iMyNode;
+		// return false;
+	}
+
+	// we'll do a rough sample to find nodes that are relatively nearby
+	for (i = 0; i < WorldGraph.m_cNodes; i++)
+	{
+		int nodeNumber = (i + WorldGraph.m_iLastCoverSearch) % WorldGraph.m_cNodes;
+
+		CNode& node = WorldGraph.Node(nodeNumber);
+
+		// could use an optimization here!!
+		flDist = (pev->origin - node.m_vecOrigin).Length();
+
+		if (flDist >= flMinDist && flDist < flMaxDist)
+		{
+			// node is also closer to me than the threat, or the same distance from myself and the threat the node is good.
+			if ((iMyNode == iThreatNode) || WorldGraph.PathLength(iMyNode, nodeNumber, iMyHullIndex, m_afCapability) <= WorldGraph.PathLength(iThreatNode, nodeNumber, iMyHullIndex, m_afCapability))
+			{
+				if (FValidateCover(node.m_vecOrigin) && MoveToLocation(ACT_RUN, 0, node.m_vecOrigin))
+				{
+					WorldGraph.m_iLastCoverSearch = nodeNumber + 1; // next monster that searches for cover node will start where we left off here.
+					return true;
+				}
+			}
+		}
+	}
+	return false;
+}
+
 
 //=========================================================
 // BuildNearestRoute - tries to build a route as close to the target
diff --git a/dlls/schedule.cpp b/dlls/schedule.cpp
index 64bb854f5..5346cff00 100644
--- a/dlls/schedule.cpp
+++ b/dlls/schedule.cpp
@@ -797,15 +797,22 @@ void CBaseMonster::StartTask(Task_t* pTask)
 			}
 			*/
 
-		if (pBestSound && FindCover(pBestSound->m_vecOrigin, g_vecZero, pBestSound->m_iVolume, CoverRadius()))
+		if (pBestSound)
 		{
-			// then try for plain ole cover
-			m_flMoveWaitFinished = gpGlobals->time + pTask->flData;
-			TaskComplete();
+			if (FindCover(pBestSound->m_vecOrigin, g_vecZero, pBestSound->m_iVolume, CoverRadius()))
+			{
+				// then try for plain ole cover
+				m_flMoveWaitFinished = gpGlobals->time + pTask->flData;
+				TaskComplete();
+			}
+			else if (FindRetreat(pBestSound->m_vecOrigin, pBestSound->m_iVolume, CoverRadius()))
+			{
+				m_flMoveWaitFinished = gpGlobals->time + pTask->flData;
+				TaskComplete();
+			}
 		}
-		else
-		{
-			// no coverwhatsoever. or no sound in list
+		// no coverwhatsoever. or no sound in list
+		if (!TaskIsComplete()) {
 			TaskFail();
 		}
 		break;