Disable angle interp on fresh mobjs

src/p_mobj.c

@@ -10593,6 +10593,8 @@ mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type)
 	// Tells MobjCheckWater that the water height was not set.
 	mobj->watertop = INT32_MAX;
 
+	mobj->resetinterp = true;
+
 	if (z == ONFLOORZ)
 	{
 		mobj->z = mobj->floorz;

src/p_mobj.h

@@ -393,6 +393,7 @@ typedef struct mobj_s
 
 	struct pslope_s *standingslope; // The slope that the object is standing on (shouldn't need synced in savegames, right?)
 
+	boolean resetinterp; // if true, some fields should not be interpolated (see R_InterpolateMobjState implementation)
 	boolean colorized; // Whether the mobj uses the rainbow colormap
 	boolean mirrored; // The object's rotations will be mirrored left to right, e.g., see frame AL from the right and AR from the left
 	fixed_t shadowscale; // If this object casts a shadow, and the size relative to radius

src/r_fps.c

@@ -272,11 +272,11 @@ void R_InterpolateMobjState(mobj_t *mobj, fixed_t frac, interpmobjstate_t *out)
 
 	if (mobj->player)
 	{
-		out->angle = R_LerpAngle(mobj->player->old_drawangle, mobj->player->drawangle, frac);
+		out->angle = mobj->resetinterp ? mobj->player->drawangle : R_LerpAngle(mobj->player->old_drawangle, mobj->player->drawangle, frac);
 	}
 	else
 	{
-		out->angle = R_LerpAngle(mobj->old_angle, mobj->angle, frac);
+		out->angle = mobj->resetinterp ? mobj->angle : R_LerpAngle(mobj->old_angle, mobj->angle, frac);
 	}
 }
 
@@ -719,6 +719,8 @@ void R_ResetMobjInterpolationState(mobj_t *mobj)
 		mobj->player->old_drawangle2 = mobj->player->old_drawangle;
 		mobj->player->old_drawangle = mobj->player->drawangle;
 	}
+
+	mobj->resetinterp = false;
 }
 
 //