- Make view angles interpolate on a separate flag to the one that forces interpolation for the entire frame.

* As view angles are an offset, there's no reason why these cannot lerp separately.

src/playsim/actor.h

@@ -923,6 +923,8 @@ public:
 	void SetPitch(DAngle p, int fflags);
 	void SetAngle(DAngle ang, int fflags);
 	void SetRoll(DAngle roll, int fflags);
+
+	// These also set CF_INTERPVIEWANGLES for players.
 	void SetViewPitch(DAngle p, int fflags);
 	void SetViewAngle(DAngle ang, int fflags);
 	void SetViewRoll(DAngle roll, int fflags);

src/playsim/d_player.h

@@ -122,6 +122,7 @@ typedef enum
 	CF_TOTALLYFROZEN	= 1 << 12,		// [RH] All players can do is press +use
 	CF_PREDICTING		= 1 << 13,		// [RH] Player movement is being predicted
 	CF_INTERPVIEW		= 1 << 14,		// [RH] view was changed outside of input, so interpolate one frame
+	CF_INTERPVIEWANGLES	= 1 << 15,		// [RH] flag for interpolating view angles without interpolating the entire frame
 	CF_EXTREMELYDEAD	= 1 << 22,		// [RH] Reliably let the status bar know about extreme deaths.
 	CF_BUDDHA2			= 1 << 24,		// [MC] Absolute buddha. No voodoo can kill it either.
 	CF_GODMODE2			= 1 << 25,		// [MC] Absolute godmode. No voodoo can kill it either.

src/playsim/p_mobj.cpp

@@ -3473,7 +3473,7 @@ void AActor::SetViewPitch(DAngle p, int fflags)
 		ViewAngles.Pitch = p;
 		if (player != nullptr && (fflags & SPF_INTERPOLATE))
 		{
-			player->cheats |= CF_INTERPVIEW;
+			player->cheats |= CF_INTERPVIEWANGLES;
 		}
 	}
 
@@ -3486,7 +3486,7 @@ void AActor::SetViewAngle(DAngle ang, int fflags)
 		ViewAngles.Yaw = ang;
 		if (player != nullptr && (fflags & SPF_INTERPOLATE))
 		{
-			player->cheats |= CF_INTERPVIEW;
+			player->cheats |= CF_INTERPVIEWANGLES;
 		}
 	}
 
@@ -3499,7 +3499,7 @@ void AActor::SetViewRoll(DAngle r, int fflags)
 		ViewAngles.Roll = r;
 		if (player != nullptr && (fflags & SPF_INTERPOLATE))
 		{
-			player->cheats |= CF_INTERPVIEW;
+			player->cheats |= CF_INTERPVIEWANGLES;
 		}
 	}
 }

src/playsim/p_user.cpp

@@ -1258,6 +1258,7 @@ void P_PlayerThink (player_t *player)
 	player->original_cmd = cmd->ucmd;
 	// Don't interpolate the view for more than one tic
 	player->cheats &= ~CF_INTERPVIEW;
+	player->cheats &= ~CF_INTERPVIEWANGLES;
 	player->mo->FloatVar("prevBob") = player->bob;
 
 	IFVIRTUALPTRNAME(player->mo, NAME_PlayerPawn, PlayerThink)

src/rendering/r_utility.cpp

@@ -80,6 +80,7 @@ struct InterpolationViewer
 	{
 		DVector3 Pos;
 		DRotator Angles;
+		DRotator ViewAngles;
 	};
 
 	AActor *ViewActor;
@@ -539,7 +540,13 @@ void R_InterpolateView (FRenderViewpoint &viewpoint, player_t *player, double Fr
 		viewpoint.Angles.Yaw = (oviewangle + deltaangle(oviewangle, nviewangle) * Frac).Normalized180();
 		viewpoint.Angles.Roll = (iview->Old.Angles.Roll + deltaangle(iview->Old.Angles.Roll, iview->New.Angles.Roll) * Frac).Normalized180();
 	}
-	
+
+	// [MR] Apply the view angles as an offset if ABSVIEWANGLES isn't specified.
+	if (!(viewpoint.camera->flags8 & MF8_ABSVIEWANGLES))
+	{
+		viewpoint.Angles += (!player || (player->cheats & CF_INTERPVIEWANGLES)) ? interpolatedvalue(iview->Old.ViewAngles, iview->New.ViewAngles, Frac) : iview->New.ViewAngles;
+	}
+
 	// Due to interpolation this is not necessarily the same as the sector the camera is in.
 	viewpoint.sector = Level->PointInRenderSubsector(viewpoint.Pos)->sector;
 	bool moved = false;
@@ -898,16 +905,10 @@ void R_SetupFrame (FRenderViewpoint &viewpoint, FViewWindow &viewwindow, AActor
 		}
 	}
 
-	// [MC] Apply the view angles first, which is the offsets. If the absolute isn't desired,
+	// [MR] Apply view angles as the viewpoint angles if asked to do so.
-	// add the standard angles on top of it.
+	iview->New.Angles = !(viewpoint.camera->flags8 & MF8_ABSVIEWANGLES) ? viewpoint.camera->Angles : viewpoint.camera->ViewAngles;
-	viewpoint.Angles = viewpoint.camera->ViewAngles;
+	iview->New.ViewAngles = viewpoint.camera->ViewAngles;
 
-	if (!(viewpoint.camera->flags8 & MF8_ABSVIEWANGLES))
-	{
-		viewpoint.Angles += viewpoint.camera->Angles;
-	}
-
-	iview->New.Angles = viewpoint.Angles;
 	if (viewpoint.camera->player != 0)
 	{
 		player = viewpoint.camera->player;

wadsrc/static/zscript/constants.zs

@@ -1137,6 +1137,7 @@ enum EPlayerCheats
 	CF_TOTALLYFROZEN	= 1 << 12,		// [RH] All players can do is press +use
 	CF_PREDICTING		= 1 << 13,		// [RH] Player movement is being predicted
 	CF_INTERPVIEW		= 1 << 14,		// [RH] view was changed outside of input, so interpolate one frame
+	CF_INTERPVIEWANGLES	= 1 << 15,		// [RH] flag for interpolating view angles without interpolating the entire frame
 
 	CF_EXTREMELYDEAD	= 1 << 22,		// [RH] Reliably let the status bar know about extreme deaths.