Refactor Shield hit handling to remove redundancy and fix related bugs (#999)

* fix #927 (#985)
* Shield hit punchangle change logic grouped
* Add comments for clarity
---------
Co-authored-by: Vaqtincha <51029683+Vaqtincha@users.noreply.github.com>

Author: dystopm

regamedll/dlls/cbase.cpp

@@ -1443,30 +1443,8 @@ VectorRef CBaseEntity::__API_HOOK(FireBullets3)(VectorRef vecSrc, VectorRef vecD
 
 			if (tr.iHitgroup == HITGROUP_SHIELD)
 			{
-				EMIT_SOUND(pEntity->edict(), CHAN_VOICE, (RANDOM_LONG(0, 1) == 1) ? "weapons/ric_metal-1.wav" : "weapons/ric_metal-2.wav", VOL_NORM, ATTN_NORM);
-				UTIL_Sparks(tr.vecEndPos);
-
-				pEntity->pev->punchangle.x = iCurrentDamage * RANDOM_FLOAT(-0.15, 0.15);
-				pEntity->pev->punchangle.z = iCurrentDamage * RANDOM_FLOAT(-0.15, 0.15);
-
-#ifndef REGAMEDLL_FIXES
-				if (pEntity->pev->punchangle.x < 4)
-#else
-				if (pEntity->pev->punchangle.x < -4)
-#endif
-				{
-					pEntity->pev->punchangle.x = -4;
-				}
-
-				if (pEntity->pev->punchangle.z < -5)
-				{
-					pEntity->pev->punchangle.z = -5;
-				}
-				else if (pEntity->pev->punchangle.z > 5)
-				{
-					pEntity->pev->punchangle.z = 5;
-				}
-
+				// stop on shield hit
+				pEntity->HitShield(iCurrentDamage, &tr);
 				break;
 			}
 
@@ -1503,6 +1481,43 @@ VectorRef CBaseEntity::__API_HOOK(FireBullets3)(VectorRef vecSrc, VectorRef vecD
 	return vecRet;
 }
 
+void CBaseEntity::HitShield(float flDamage, TraceResult *ptr)
+{
+	if (RANDOM_LONG(0, 1))
+		EMIT_SOUND(ENT(pev), CHAN_VOICE, "weapons/ric_metal-1.wav", VOL_NORM, ATTN_NORM);
+	else
+		EMIT_SOUND(ENT(pev), CHAN_VOICE, "weapons/ric_metal-2.wav", VOL_NORM, ATTN_NORM);
+
+	UTIL_Sparks(ptr->vecEndPos);
+
+#ifdef REGAMEDLL_FIXES
+	// dont modify punchangle if it is already above this threshold
+	if (Q_fabs(pev->punchangle.x) < 4.0)
+	{
+		pev->punchangle.x = clamp(flDamage * RANDOM_FLOAT(-0.15, 0.15), -4.0f, 4.0f);
+	}
+#else
+	pev->punchangle.x = flDamage * RANDOM_FLOAT(-0.15, 0.15);
+
+	if (pev->punchangle.x < 4) // BUGBUG: https://github.com/rehlds/ReGameDLL_CS/pull/919
+		pev->punchangle.x = -4;
+#endif
+
+#ifdef REGAMEDLL_FIXES
+	// dont modify punchangle if it is already above this threshold
+	if (Q_fabs(pev->punchangle.z) < 5.0)
+#endif
+	{
+		pev->punchangle.z = clamp(flDamage * RANDOM_FLOAT(-0.15, 0.15), -5.0f, 5.0f);
+		// the code above is replicated as:
+		//	if (pev->punchangle.z < -5) 
+		//		pev->punchangle.z = -5;
+		//	else if (pev->punchangle.z > 5) 
+		//		pev->punchangle.z = 5;
+		// which is the original logic
+	}
+}
+
 void CBaseEntity::TraceBleed(float flDamage, Vector vecDir, TraceResult *ptr, int bitsDamageType)
 {
 	if (BloodColor() == DONT_BLEED)

regamedll/dlls/cbase.h

@@ -162,6 +162,7 @@ class CBaseEntity {
 	bool Intersects(const Vector &mins, const Vector &maxs);
 	bool CanTakeHealth(float flHealth = 0.0f) const;
 	void MakeDormant();
+	void HitShield(float flDamage, TraceResult* ptr);
 
 	// This entity's classname.
 	const char *GetClassname() const { return pev->classname.str(); }

regamedll/dlls/player.cpp

@@ -698,27 +698,19 @@ void EXT_FUNC CBasePlayer::__API_HOOK(TraceAttack)(entvars_t *pevAttacker, float
 
 	if (bHitShield)
 	{
+#ifndef REGAMEDLL_FIXES
+		// BUGBUG: zeroing out damage BEFORE altering victim's punchangle
+		// will simply nullify any previous punchangles
 		flDamage = 0;
-		bShouldBleed = false;
-
-		if (RANDOM_LONG(0, 1))
-			EMIT_SOUND(ENT(pev), CHAN_VOICE, "weapons/ric_metal-1.wav", VOL_NORM, ATTN_NORM);
-		else
-			EMIT_SOUND(ENT(pev), CHAN_VOICE, "weapons/ric_metal-2.wav", VOL_NORM, ATTN_NORM);
-
-		UTIL_Sparks(ptr->vecEndPos);
-
-		pev->punchangle.x = flDamage * RANDOM_FLOAT(-0.15, 0.15);
-		pev->punchangle.z = flDamage * RANDOM_FLOAT(-0.15, 0.15);
-
-		if (pev->punchangle.x < 4)
-			pev->punchangle.x = -4;
+#endif
 
-		if (pev->punchangle.z < -5)
-			pev->punchangle.z = -5;
+		bShouldBleed = false;
+		HitShield(flDamage, ptr);
 
-		else if (pev->punchangle.z > 5)
-			pev->punchangle.z = 5;
+#ifdef REGAMEDLL_FIXES
+		// reset damage after messing with victim's punchangle
+		flDamage = 0;
+#endif
 	}
 	else
 	{