Fix bullet penetration rendering multiple tracers (#1895)

* Draw at most 1 tracer per shot

The bullet penetration logic is recursive, and this could cause bullets
to render multiple tracers per one shot. Check that the current
penetrating force of the shot equals the used weapon's original
penetrating force, i.e. that no surfaces have yet been penetrated.

This asserts that any penetrated surfaces will incur a non-zero
penetration cost.

* Remove dead code

Author: Rainyan

src/game/shared/baseentity_shared.cpp

@@ -1779,9 +1779,11 @@ void CBaseEntity::FireBullets( const FireBulletsInfo_t &info )
 	CShotManipulator Manipulator( info.m_vecDirShooting );
 #endif
 
+#ifndef NEO
 	bool bDoImpacts = false;
 	bool bDoTracers = false;
-	
+#endif
+
 	float flCumulativeDamage = 0.0f;
 
 	for (int iShot = 0; iShot < info.m_iShots; iShot++)
@@ -2050,10 +2052,12 @@ void CBaseEntity::FireBullets( const FireBulletsInfo_t &info )
 					{
 						DoImpactEffect( tr, nDamageType );
 					}
+#ifndef NEO
 					else
 					{
 						bDoImpacts = true;
 					}
+#endif
 				}
 				else
 				{
@@ -2107,6 +2111,19 @@ void CBaseEntity::FireBullets( const FireBulletsInfo_t &info )
 		}
 #endif // NEO
 
+#ifdef NEO
+		// The below penetration value check relies an all possible surfaces
+		// incurring a non-zero cost to m_flPenetration.
+		for (int i = 0; i < ARRAYSIZE(PENETRATION_RESISTANCE); ++i)
+		{
+			Assert(PENETRATION_RESISTANCE[i] > 0);
+		}
+		// Only draw tracers if we haven't yet penetrated, because the penetration logic is reentrant
+		// and would otherwise draw multiple tracers per shot.
+		Assert(neoWeapon);
+		if (neoWeapon->GetPenetration() == info.m_flPenetration)
+		{
+#endif
 		if ( ( info.m_iTracerFreq != 0 ) && ( tracerCount++ % info.m_iTracerFreq ) == 0 && ( bHitGlass == false ) )
 		{
 			if ( bDoServerEffects == true )
@@ -2150,11 +2167,16 @@ void CBaseEntity::FireBullets( const FireBulletsInfo_t &info )
 				}
 #endif //#ifdef PORTAL
 			}
+#ifndef NEO
 			else
 			{
 				bDoTracers = true;
 			}
+#endif
+		}
+#ifdef NEO
 		}
+#endif
 
 		//NOTENOTE: We could expand this to a more general solution for various material penetration types (wood, thin metal, etc)