Viewmodel reacting to obstacles

src/game/shared/neo/neo_predicted_viewmodel.cpp

@@ -502,7 +502,33 @@ void CNEOPredictedViewModel::CalcViewModelView(CBasePlayer *pOwner,
 			m_angOffset = angOffset;
 		}
 
-		newPos += vForward * vOffset.x;
+		constexpr int VIEWMODEL_MOVE_DISTANCE = 32; // max distance viewmodel can move is actually (1 - 0.375) * VIEWMODEL_MOVE_DISTANCE
+		if (m_flGunPushLastChangeTime < gpGlobals->curtime) // Why is this value sometimes greater than current time? Also this fixes gun moving back much slower around some corners, maybe weird prediction stuff?
+		{
+			constexpr float MAX_GUN_PUSH_FRACTION_CHANGE_PER_SECOND = 2.5f;
+			float maxFractionChange = (gpGlobals->curtime - m_flGunPushLastChangeTime) * MAX_GUN_PUSH_FRACTION_CHANGE_PER_SECOND;
+			m_flGunPushLastChangeTime = gpGlobals->curtime;
+
+			trace_t tr;
+			Vector startPos = pOwner->EyePosition();
+			Vector endPos = pOwner->EyePosition() + (vForward * VIEWMODEL_MOVE_DISTANCE);
+			// NEO NOTE (Adam) the hull generated by tracehull is fixed to the axis, using a non square cube shape will give varying results depending on player orientation to the obstacle in front of them (already the case to an extend since not using a sphere)
+			UTIL_TraceHull(startPos, endPos, Vector(-4,-4,-4), Vector(4,4,4), MASK_SHOT_HULL, pOwner, COLLISION_GROUP_NONE, &tr);
+			tr.fraction = max(0.375, tr.fraction); // The smallest value tr.fraction can have given the size of the player hull. Stuff we want the viewmodel to react to like players don't collide with our playerhull (depending on the settings) at which point tr.fraction can be as low as 0
+
+			if (abs(tr.fraction - m_flGunPush) < (maxFractionChange + 0.01)) // float math, don't want the gun to move when in its resting position
+			{
+				m_flGunPush = tr.fraction;
+			}
+			else
+			{
+				m_flGunPush += tr.fraction > m_flGunPush ? maxFractionChange : -maxFractionChange;
+			}
+
+		}
+		Vector finalGunPush = vForward * ((1 - m_flGunPush) * VIEWMODEL_MOVE_DISTANCE);
+
+		newPos += (vForward * vOffset.x) - finalGunPush;
 		newPos += vRight * vOffset.y;
 		newPos += vUp * vOffset.z;
 	}

src/game/shared/neo/neo_predicted_viewmodel.h

@@ -66,6 +66,8 @@ class CNEOPredictedViewModel : public CPredictedViewModel
 	float m_flLeanRatio;
 	CInterpolatedVar<float> m_iv_flLeanRatio;
 #endif
+	float m_flGunPush = 0.f;
+	float m_flGunPushLastChangeTime = 0.f;
 
 private:
 	float m_flStartAimingChange;