Added interpolated_shoot_position

While the old fix was working, it was a bit too much noticeable while
surfing, this is an issue we don't want.
We need a proper check for cheaters too.

engine/host.cpp

@@ -3145,33 +3145,42 @@ void _Host_RunFrame (float time)
 #ifndef SWDS
     const auto CalcInterpolationAmount = [&]()
     {
-		// TODO_ENHANCED:
+        // TODO_ENHANCED:
-		// Notice_Enhanced:
+        // This check permits to fix interpolation problems on the
-		// This check permits to fix interpolation problems on the
+        // local player that valve has been (fucking finally)
-		// local player that valve has been (fucking finally)
+        // caring about on counter-strike 2.
-		// caring about on counter-strike 2.
+        //
-		//
+        // To recall the original issue, the
-		// To recall the original issue, the
+        // problem that Valve cared about is that interpolation
-		// problem that Valve cared about is that interpolation
+        // had some problems with interpolating the local
-		// had some problems with interpolating the local
+        // player because the screen would never in the first
-		// player because the screen would never in the first
+        // place match the tick "screen", because interpolation
-		// place match the tick "screen", because interpolation
+        // amount could never reach 0.0 or 1.0
-		// amount could never reach 0.0 or 1.0
+        //
-		//
+        // Valve solution was to introduce bugs with lag
-		// Valve solution was to introduce bugs with lag
+        // compensating the local player and made the game worse,
-		// compensating the local player and made the game worse,
+        // introducing a new way for cheaters to cheat even more
-		// introducing a new way for cheaters to cheat even more
+        // on their games.
-		// on their games.
+        // I'm joking, but you can clearly see the outcome anyway.
-		// I'm joking, but you can clearly see the outcome anyway.
+        //
-		//
+        // My solution is to simply set interpolation amount
-		// My solution is to simply set interpolation amount
+        // to 0.0 when a tick arrives.
-		// to 0.0 when a tick arrives.
+        //
-		//
+        // So when we shoot, we get the frame we shot with an
-		// So when we shoot, we get the frame we shot with an
+        // interpolation amount at 0.0, perfectly aligned to user
-		// interpolation amount at 0.0, perfectly aligned to user
+        // commands which is ideal for us.
-		// commands which is ideal for us.
+        //
-		//
+        // README_ENHANCED:
-		// Now includes smoothing.
+        // Unfortunately, some players still notice it with low enough fps.
+        // This is a problem; we return then to lag compensating the local player.
+        // Two choices here:
+        //
+        // 1) For precision we might need to send camera position, that is proven to work.
+        // 2) Send interpolation_amount so we calculate it server and in runcommand.
+        //
+		// Both works, but the first one requires validation,
+		// the second doesn't at the expense of some unprecisions due to floats.
+		// The first one is the easier route to avoid issues.
 
 		static ConVar cl_interpolation_amount_fix("cl_interpolation_amount_fix", "0", FCVAR_HIDDEN);
 

game/client/in_main.cpp

@@ -1330,6 +1330,17 @@ void CInput::CreateMove ( int sequence_number, float input_sample_frametime, boo
     }
 #endif
 
+    C_BasePlayer* pPlayer = C_BasePlayer::GetLocalPlayer();
+
+    if (pPlayer)
+    {
+        cmd->interpolated_shoot_position = pPlayer->Weapon_ShootPosition();
+	}
+    else
+    {
+        cmd->interpolated_shoot_position.Init();
+    }
+
 	pVerified->m_cmd = *cmd;
 	pVerified->m_crc = cmd->GetChecksum();
 }

game/shared/cstrike/fx_cs_shared.cpp

@@ -119,6 +119,9 @@ void FX_FireBullets(
 	float flSoundTime
 	)
 {
+    // Fallback if failed to find the interpolated shoot position.
+    Vector vHookedOrigin = vOrigin;
+
     if (weapon_accuracy_noinaccuracy.GetBool())
     {
         fInaccuracy = 0.0f;
@@ -132,6 +135,19 @@ void FX_FireBullets(
 	CCSPlayer *pPlayer = ToCSPlayer( UTIL_PlayerByIndex( iPlayerIndex) );
 #endif
 
+    // TODO_ENHANCED:
+    // Check if interpolated_shoot_position is within interpolation bounds! (between old shoot pos and new)
+    // This is to check for cheaters abusing the shooting position.
+
+    if (pPlayer)
+    {
+#ifdef CLIENT_DLL
+    if (pPlayer->m_pCurrentCommand) { vHookedOrigin = pPlayer->m_pCurrentCommand->interpolated_shoot_position; }
+#else
+    if (pPlayer->GetCurrentCommand()) { vHookedOrigin = pPlayer->GetCurrentCommand()->interpolated_shoot_position; }
+#endif
+	}
+    
 	const char * weaponAlias =	WeaponIDToAlias( iWeaponID );
 
 	if ( !weaponAlias )
@@ -195,7 +211,7 @@ void FX_FireBullets(
 	// Dispatch one message for all the bullet impacts and sounds.
 	TE_FireBullets( 
 		iPlayerIndex,
-		vOrigin, 
+		vHookedOrigin, 
 		vAngles, 
 		iWeaponID,
 		iMode,
@@ -250,7 +266,7 @@ void FX_FireBullets(
 
 	if ( bDoEffects)
 	{
-		FX_WeaponSound( iPlayerIndex, sound_type, vOrigin, pWeaponInfo, flSoundTime );
+		FX_WeaponSound( iPlayerIndex, sound_type, vHookedOrigin, pWeaponInfo, flSoundTime );
 	}
 
 
@@ -301,7 +317,7 @@ void FX_FireBullets(
 #endif
         pPlayer->FireBullet(
 			iBullet,
-			vOrigin,
+			vHookedOrigin,
 			vAngles,
 			flRange,
 			iPenetration,

game/shared/usercmd.h

@@ -105,6 +105,8 @@ public:
 #if defined( HL2_DLL ) || defined( HL2_CLIENT_DLL )
 		entitygroundcontact.RemoveAll();
 #endif
+
+        interpolated_shoot_position.Init();
 	}
 
 	CUserCmd& operator =( const CUserCmd& src )
@@ -137,6 +139,7 @@ public:
 		entitygroundcontact			= src.entitygroundcontact;
 #endif
 
+        interpolated_shoot_position = src.interpolated_shoot_position;
 		return *this;
 	}
 
@@ -165,6 +168,7 @@ public:
         CRC32_ProcessBuffer(&crc, &mousedy, sizeof(mousedy));
         CRC32_ProcessBuffer(&crc, simulationdata, sizeof(simulationdata));
         CRC32_ProcessBuffer(&crc, &debug_hitboxes, sizeof(debug_hitboxes));
+        CRC32_ProcessBuffer( &crc, &interpolated_shoot_position, sizeof(interpolated_shoot_position));
 		CRC32_Final( &crc );
 
 		return crc;
@@ -179,7 +183,8 @@ public:
 		upmove = 0.f;
 		buttons = 0;
 		impulse = 0;
-		debug_hitboxes = DEBUG_HITBOXES_OFF;
+        debug_hitboxes = DEBUG_HITBOXES_OFF;
+        interpolated_shoot_position.Init();
 	}
 
 	// For matching server and client commands for debugging
@@ -226,6 +231,9 @@ public:
 
 	uint8 debug_hitboxes;
 
+    // TODO_ENHANCED: check README_ENHANCED in host.cpp!
+    Vector interpolated_shoot_position;
+
 	// Back channel to communicate IK state
 #if defined( HL2_DLL ) || defined( HL2_CLIENT_DLL )
 	CUtlVector< CEntityGroundContact > entitygroundcontact;