Add CF_INTERPVIEW for players.

- Added CF_INTERPVIEW flag for players. A_SetPitch/A_SetAngle and the
  similar ACS APROPs set this when changing an angle. This forces the
  renderer to interpolate the view angles instead of updating with the
  latest mouse positions. The effect lasts one tick.

src/actor.h

@@ -764,6 +764,10 @@ public:
 		return (PalEntry)GetClass()->Meta.GetMetaInt(AMETA_BloodColor);
 	}
 
+	// These also set CF_INTERPVIEW for players.
+	void SetPitch(int p);
+	void SetAngle(angle_t ang);
+
 	const PClass *GetBloodType(int type = 0) const
 	{
 		const PClass *bloodcls;

src/d_player.h

@@ -198,6 +198,7 @@ typedef enum
 	CF_INSTANTWEAPSWITCH= 1 << 11,		// [RH] Switch weapons instantly
 	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_DRAIN			= 1 << 16,		// Player owns a drain powerup
 	CF_HIGHJUMP			= 1 << 18,		// more Skulltag flags. Implementation not guaranteed though. ;)
 	CF_REFLECTION		= 1 << 19,

src/p_acs.cpp

@@ -8250,7 +8250,9 @@ scriptwait:
 			if (STACK(2) == 0)
 			{
 				if (activator != NULL)
-					activator->angle = STACK(1) << 16;
+				{
+					activator->SetAngle(STACK(1) << 16);
+				}
 			}
 			else
 			{
@@ -8259,7 +8261,7 @@ scriptwait:
 
 				while ( (actor = iterator.Next ()) )
 				{
-					actor->angle = STACK(1) << 16;
+					actor->SetAngle(STACK(1) << 16);
 				}
 			}
 			sp -= 2;
@@ -8269,7 +8271,9 @@ scriptwait:
 			if (STACK(2) == 0)
 			{
 				if (activator != NULL)
-					activator->pitch = STACK(1) << 16;
+				{
+					activator->SetPitch(STACK(1) << 16);
+				}
 			}
 			else
 			{
@@ -8278,7 +8282,7 @@ scriptwait:
 
 				while ( (actor = iterator.Next ()) )
 				{
-					actor->pitch = STACK(1) << 16;
+					actor->SetPitch(STACK(1) << 16);
 				}
 			}
 			sp -= 2;

src/p_mobj.cpp

@@ -2962,6 +2962,30 @@ void AActor::SetShade (int r, int g, int b)
 	fillcolor = MAKEARGB(ColorMatcher.Pick (r, g, b), r, g, b);
 }
 
+void AActor::SetPitch(int p)
+{
+	if (p != pitch)
+	{
+		pitch = p;
+		if (player != NULL)
+		{
+			player->cheats |= CF_INTERPVIEW;
+		}
+	}
+}
+
+void AActor::SetAngle(angle_t ang)
+{
+	if (ang != angle)
+	{
+		angle = ang;
+		if (player != NULL)
+		{
+			player->cheats |= CF_INTERPVIEW;
+		}
+	}
+}
+
 //
 // P_MobjThinker
 //

src/p_user.cpp

@@ -2252,6 +2252,9 @@ void P_PlayerThink (player_t *player)
 	{
 		player->inventorytics--;
 	}
+	// Don't interpolate the view for more than one tic
+	player->cheats &= ~CF_INTERPVIEW;
+
 	// No-clip cheat
 	if ((player->cheats & (CF_NOCLIP | CF_NOCLIP2)) == CF_NOCLIP2)
 	{ // No noclip2 without noclip

src/r_utility.cpp

@@ -581,6 +581,7 @@ void R_InterpolateView (player_t *player, fixed_t frac, InterpolationViewer *ivi
 	viewy = iview->oviewy + FixedMul (frac, iview->nviewy - iview->oviewy);
 	viewz = iview->oviewz + FixedMul (frac, iview->nviewz - iview->oviewz);
 	if (player != NULL &&
+		!(player->cheats & CF_INTERPVIEW) &&
 		player - players == consoleplayer &&
 		camera == player->mo &&
 		!demoplayback &&

src/thingdef/thingdef_codeptr.cpp

@@ -3935,7 +3935,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_SetAngle)
 {
 	ACTION_PARAM_START(1);
 	ACTION_PARAM_ANGLE(angle, 0);
-	self->angle = angle;
+	self->SetAngle(angle);
 }
 
 //===========================================================================
@@ -3973,8 +3973,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_SetPitch)
 		}
 		pitch = clamp<int>(pitch, min, max);
 	}
-
+	self->SetPitch(pitch);
-	self->pitch = pitch;
 }
 
 //===========================================================================