From a1cf2d38bbb2df8947183652568e6132152979b0 Mon Sep 17 00:00:00 2001
From: Sam V <sam.vanheer@outlook.com>
Date: Mon, 14 Aug 2023 13:03:37 +0200
Subject: [PATCH] Add cvar sv_allowbunnyhopping to control whether the bunny
 hopping limiter is enabled

---
 CHANGELOG.md            |  4 ++++
 dlls/client.cpp         | 20 ++++++++++++++++++++
 dlls/game.cpp           |  4 ++++
 dlls/game.h             |  2 ++
 dlls/player.cpp         |  1 +
 pm_shared/pm_shared.cpp |  7 +++++++
 6 files changed, 38 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79266906d..2734f9832 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@
 * Fixed hand grenade animations not playing correctly [#209](https://github.com/SamVanheer/halflife-updated/pull/209) (Thanks Toodles2You)
 * Fixed out of bounds access in studiomodel renderer bone setup code (halflife issue [#3360](https://github.com/ValveSoftware/halflife/issues/3360))
 
+### Features
+
+* Added cvar `sv_allowbunnyhopping` to control whether the bunny hopping limiter is enabled (halflife issue [#11](https://github.com/ValveSoftware/halflife/issues/11))
+
 ## Changes in V1.0.0 Release Candidate 001
 
 ### Bug fixes
diff --git a/dlls/client.cpp b/dlls/client.cpp
index dc3d795a4..145ff0fe2 100644
--- a/dlls/client.cpp
+++ b/dlls/client.cpp
@@ -773,6 +773,7 @@ void ParmsChangeLevel()
 		pSaveData->connectionCount = BuildChangeList(pSaveData->levelList, MAX_LEVEL_CONNECTIONS);
 }
 
+static bool g_LastAllowBunnyHoppingState = false;
 
 //
 // GLOBALS ASSUMED SET:  g_ulFrameCount
@@ -787,6 +788,25 @@ void StartFrame()
 
 	gpGlobals->teamplay = teamplay.value;
 	g_ulFrameCount++;
+
+	const bool allowBunnyHopping = sv_allowbunnyhopping.value != 0;
+
+	if (allowBunnyHopping != g_LastAllowBunnyHoppingState)
+	{
+		g_LastAllowBunnyHoppingState = allowBunnyHopping;
+
+		for (int i = 1; i <= gpGlobals->maxClients; ++i)
+		{
+			auto player = UTIL_PlayerByIndex(i);
+
+			if (!player)
+			{
+				continue;
+			}
+
+			g_engfuncs.pfnSetPhysicsKeyValue(player->edict(), "bj", UTIL_dtos1(allowBunnyHopping ? 1 : 0));
+		}
+	}
 }
 
 
diff --git a/dlls/game.cpp b/dlls/game.cpp
index 6ac437630..d99c486da 100644
--- a/dlls/game.cpp
+++ b/dlls/game.cpp
@@ -44,6 +44,8 @@ cvar_t allow_spectators = {"allow_spectators", "0.0", FCVAR_SERVER}; // 0 preven
 
 cvar_t mp_chattime = {"mp_chattime", "10", FCVAR_SERVER};
 
+cvar_t sv_allowbunnyhopping = {"sv_allowbunnyhopping", "0", FCVAR_SERVER};
+
 //CVARS FOR SKILL LEVEL SETTINGS
 // Agrunt
 cvar_t sk_agrunt_health1 = {"sk_agrunt_health1", "0"};
@@ -493,6 +495,8 @@ void GameDLLInit()
 
 	CVAR_REGISTER(&mp_chattime);
 
+	CVAR_REGISTER(&sv_allowbunnyhopping);
+
 	// REGISTER CVARS FOR SKILL LEVEL STUFF
 	// Agrunt
 	CVAR_REGISTER(&sk_agrunt_health1); // {"sk_agrunt_health1","0"};
diff --git a/dlls/game.h b/dlls/game.h
index f2b8e6ba2..3e759521f 100644
--- a/dlls/game.h
+++ b/dlls/game.h
@@ -41,6 +41,8 @@ extern cvar_t allowmonsters;
 extern cvar_t allow_spectators;
 extern cvar_t mp_chattime;
 
+extern cvar_t sv_allowbunnyhopping;
+
 // Engine Cvars
 inline cvar_t* g_psv_gravity;
 inline cvar_t* g_psv_aim;
diff --git a/dlls/player.cpp b/dlls/player.cpp
index f0100ffa5..6b3161f94 100644
--- a/dlls/player.cpp
+++ b/dlls/player.cpp
@@ -2806,6 +2806,7 @@ void CBasePlayer::Spawn()
 
 	g_engfuncs.pfnSetPhysicsKeyValue(edict(), "slj", "0");
 	g_engfuncs.pfnSetPhysicsKeyValue(edict(), "hl", "1");
+	g_engfuncs.pfnSetPhysicsKeyValue(edict(), "bj", UTIL_dtos1(sv_allowbunnyhopping.value != 0 ? 1 : 0));
 
 	m_iFOV = 0;		   // init field of view.
 	m_iClientFOV = -1; // make sure fov reset is sent
diff --git a/pm_shared/pm_shared.cpp b/pm_shared/pm_shared.cpp
index c54b73315..612e5ad2b 100644
--- a/pm_shared/pm_shared.cpp
+++ b/pm_shared/pm_shared.cpp
@@ -2525,6 +2525,13 @@ void PM_NoClip()
 //-----------------------------------------------------------------------------
 void PM_PreventMegaBunnyJumping()
 {
+	const bool allowBunnyHopping = atoi(pmove->PM_Info_ValueForKey(pmove->physinfo, "bj")) == 1;
+
+	if (allowBunnyHopping)
+	{
+		return;
+	}
+
 	// Current player speed
 	float spd;
 	// If we have to crop, apply this cropping fraction to velocity