Re-attempt at hitlag

I remember when I tried to fix wolfs' branch I was having issues, but this ended up working pretty much fine? Don't remember why the old branch was messed up though (it was simply too old & not substantial enough to try and work off of imo)

src/k_collide.c

@@ -48,6 +48,7 @@ boolean K_OrbinautJawzCollide(mobj_t *t1, mobj_t *t2)
 			P_DamageMobj(t2, t1, t1->target, 1);
 			K_KartBouncing(t2, t1, false, false);
 			S_StartSound(t2, sfx_s3k7b);
+			t2->hitlag = TICRATE;
 		}
 
 		damageitem = true;
@@ -99,6 +100,8 @@ boolean K_OrbinautJawzCollide(mobj_t *t1, mobj_t *t2)
 		else
 			t1->z += t1->height;
 
+		t1->hitlag = TICRATE;
+
 		S_StartSound(t1, t1->info->deathsound);
 		P_KillMobj(t1, t2, t2);
 

src/lua_mobjlib.c

@@ -87,6 +87,7 @@ enum mobj_e {
 	mobj_standingslope,
 #endif
 	mobj_colorized,
+	mobj_hitlag,
 	mobj_shadowscale,
 	mobj_whiteshadow,
 	mobj_sprxoff,
@@ -156,6 +157,7 @@ static const char *const mobj_opt[] = {
 	"standingslope",
 #endif
 	"colorized",
+	"hitlag",
 	"shadowscale",
 	"whiteshadow",
 	"sprxoff",
@@ -375,6 +377,9 @@ static int mobj_get(lua_State *L)
 	case mobj_colorized:
 		lua_pushboolean(L, mo->colorized);
 		break;
+	case mobj_hitlag:
+		lua_pushinteger(L, mo->hitlag);
+		break;
 	case mobj_shadowscale:
 		lua_pushfixed(L, mo->shadowscale);
 		break;
@@ -710,6 +715,9 @@ static int mobj_set(lua_State *L)
 	case mobj_colorized:
 		mo->colorized = luaL_checkboolean(L, 3);
 		break;
+	case mobj_hitlag:
+		mo->hitlag = luaL_checkinteger(L, 3);
+		break;
 	case mobj_shadowscale:
 		mo->shadowscale = luaL_checkfixed(L, 3);
 		break;

src/p_map.c

@@ -2598,6 +2598,12 @@ boolean P_TryMove(mobj_t *thing, fixed_t x, fixed_t y, boolean allowdropoff)
 	if (radius < mapobjectscale)
 		radius = mapobjectscale;
 
+	if (thing->hitlag > 0)
+	{
+		// Do not move during hitlag
+		return false;
+	}
+
 	do {
 		if (thing->flags & MF_NOCLIP) {
 			tryx = x;

src/p_mobj.c

@@ -6392,6 +6392,12 @@ void P_MobjThinker(mobj_t *mobj)
 	if (mobj->flags & MF_NOTHINK)
 		return;
 
+	if (mobj->hitlag > 0)
+	{
+		mobj->hitlag--;
+		return;
+	}
+
 	// Remove dead target/tracer.
 	if (mobj->target && P_MobjWasRemoved(mobj->target))
 		P_SetTarget(&mobj->target, NULL);
@@ -10875,6 +10881,8 @@ mobj_t *P_SpawnMobj(fixed_t x, fixed_t y, fixed_t z, mobjtype_t type)
 
 	mobj->colorized = false;
 
+	mobj->hitlag = 0;
+
 	// Set shadowscale here, before spawn hook so that Lua can change it
 	P_DefaultMobjShadowScale(mobj);
 

src/p_mobj.h

@@ -410,6 +410,8 @@ typedef struct mobj_s
 
 	fixed_t sprxoff, spryoff, sprzoff; // Sprite offsets in real space, does NOT affect position or collision
 
+	INT32 hitlag;
+
 	// WARNING: New fields must be added separately to savegame and Lua.
 } mobj_t;
 

src/p_saveg.c

@@ -1000,6 +1000,7 @@ typedef enum
 #endif
 	MD2_SHADOWSCALE = 1<<14,
 	MD2_DRAWFLAGS   = 1<<15,
+	MD2_HITLAG      = 1<<16
 } mobj_diff2_t;
 
 typedef enum
@@ -1196,12 +1197,14 @@ static void SaveMobjThinker(const thinker_t *th, const UINT8 type)
 	if (mobj->standingslope)
 		diff2 |= MD2_SLOPE;
 #endif
+	if (mobj->colorized)
+		diff2 |= MD2_COLORIZED;
 	if (mobj->shadowscale)
 		diff2 |= MD2_SHADOWSCALE;
 	if (mobj->drawflags)
 		diff2 |= MD2_DRAWFLAGS;
-	if (mobj->colorized)
-		diff2 |= MD2_COLORIZED;
+	if (mobj->hitlag)
+		diff2 |= MD2_HITLAG;
 	if (mobj == waypointcap)
 		diff2 |= MD2_WAYPOINTCAP;
 	if (mobj == kitemcap)
@@ -1342,6 +1345,8 @@ static void SaveMobjThinker(const thinker_t *th, const UINT8 type)
 
 		WRITEUINT16(save_p, df);
 	}
+	if (diff2 & MD2_HITLAG)
+		WRITEINT32(save_p, mobj->hitlag);
 
 	WRITEUINT32(save_p, mobj->mobjnum);
 }
@@ -2273,6 +2278,8 @@ static void LoadMobjThinker(actionf_p1 thinker)
 		mobj->shadowscale = READFIXED(save_p);
 	if (diff2 & MD2_DRAWFLAGS)
 		mobj->drawflags = READUINT16(save_p);
+	if (diff2 & MD2_HITLAG)
+		mobj->hitlag = READINT32(save_p);
 
 	if (diff & MD_REDFLAG)
 	{

src/p_user.c

@@ -8677,6 +8677,11 @@ void P_PlayerThink(player_t *player)
 	}
 #endif
 
+	if (player->mo->hitlag > 0)
+	{
+		return;
+	}
+
 	if (player->awayviewmobj && P_MobjWasRemoved(player->awayviewmobj))
 	{
 		P_SetTarget(&player->awayviewmobj, NULL); // remove awayviewmobj asap if invalid

src/r_things.c

@@ -1429,9 +1429,9 @@ static void R_ProjectDropShadow(mobj_t *thing, vissprite_t *vis, fixed_t scale,
 //
 static void R_ProjectSprite(mobj_t *thing)
 {
-	const fixed_t thingxpos = thing->x + thing->sprxoff;
-	const fixed_t thingypos = thing->y + thing->spryoff;
-	const fixed_t thingzpos = thing->z + thing->sprzoff;
+	fixed_t thingxpos = thing->x + thing->sprxoff;
+	fixed_t thingypos = thing->y + thing->spryoff;
+	fixed_t thingzpos = thing->z + thing->sprzoff;
 
 	fixed_t tr_x, tr_y;
 	fixed_t gxt, gyt;
@@ -1468,6 +1468,14 @@ static void R_ProjectSprite(mobj_t *thing)
 	INT32 light = 0;
 	fixed_t this_scale = thing->scale;
 
+	// hitlag vibrating
+	if (thing->hitlag > 0 && (leveltime & 1))
+	{
+		thingxpos += thing->momx;
+		thingypos += thing->momy;
+		thingzpos += thing->momz;
+	}
+
 	// transform the origin point
 	tr_x = thingxpos - viewx;
 	tr_y = thingypos - viewy;