Engine: store character following params as 32-bit values

Common/ac/characterinfo.cpp

@@ -31,8 +31,8 @@ void CharacterInfo::ReadBaseFields(Stream *in)
     y = in->ReadInt32();
     wait = in->ReadInt32();
     flags = in->ReadInt32();
-    following = in->ReadInt16();
-    followinfo = in->ReadInt16();
+    legacy_following = in->ReadInt16();
+    legacy_followinfo = in->ReadInt16();
     idleview = in->ReadInt32();
     idletime = in->ReadInt16();
     idleleft = in->ReadInt16();
@@ -78,8 +78,8 @@ void CharacterInfo::WriteBaseFields(Stream *out) const
     out->WriteInt32(y);
     out->WriteInt32(wait);
     out->WriteInt32(flags);
-    out->WriteInt16(following);
-    out->WriteInt16(followinfo);
+    out->WriteInt16(0); // legacy_following
+    out->WriteInt16(0); // legacy_followinfo
     out->WriteInt32(idleview);
     out->WriteInt16(idletime);
     out->WriteInt16(idleleft);

Common/ac/characterinfo.h

@@ -93,6 +93,7 @@ enum CharacterSvgVersion
     kCharSvgVersion_36025   = 2, // animation volume
     kCharSvgVersion_36109   = 3, // removed movelists, save externally
     kCharSvgVersion_36115   = 4, // no limit on character name's length
+    kCharSvgVersion_36205   = 3060205, // 32-bit "following" parameters
 };
 
 
@@ -121,8 +122,8 @@ struct CharacterInfo
     int     y           = 0;
     int     wait        = 0;
     int     flags       = 0;  // CHF_* flags
-    int16_t following   = -1;
-    int16_t followinfo  = 0;
+    int16_t legacy_following = -1;  // deprecated 16-bit values that store follow params
+    int16_t legacy_followinfo = 0;  // -- left for the script and plugin compatibility only
     int     idleview    = 0;  // the loop will be randomly picked
     int16_t idletime    = 0;
     int16_t idleleft    = 0; // num seconds idle before playing anim
@@ -186,32 +187,35 @@ struct CharacterInfo
             ((delay & 0xFF) << 8);
     }
 
+    // Gets legacy follow distance, limited to a 8-bit unsigned value
     inline int get_follow_distance() const
     {
-        return (followinfo == FOLLOW_ALWAYSONTOP) ? FOLLOW_ALWAYSONTOP : (followinfo >> 8);
+        return (legacy_followinfo == FOLLOW_ALWAYSONTOP) ? FOLLOW_ALWAYSONTOP : (legacy_followinfo >> 8);
     }
+    // Gets legacy follow eagerness, limited to a 8-bit unsigned value
     inline int get_follow_eagerness() const
     {
-        return (followinfo == FOLLOW_ALWAYSONTOP) ? 0 : (followinfo & 0xFF);
+        return (legacy_followinfo == FOLLOW_ALWAYSONTOP) ? 0 : (legacy_followinfo & 0xFF);
     }
     inline bool get_follow_sort_behind() const
     {
         return (flags & CHF_BEHINDSHEPHERD) != 0;
     }
 
-    // Sets "following" flags and followinfo values
+    // Sets "following" flags;
+    // sets legacy "followinfo" values: this is for plugin API and old script API compatibility
     void set_following(int16_t follow_whom, int dist = 0, int eagerness = 0, bool sort_behind = false)
     {
-        following = follow_whom;
+        legacy_following = follow_whom;
         if (dist == FOLLOW_ALWAYSONTOP)
         {
             flags = (flags & ~CHF_BEHINDSHEPHERD) | (CHF_BEHINDSHEPHERD * sort_behind);
-            followinfo = FOLLOW_ALWAYSONTOP;
+            legacy_followinfo = FOLLOW_ALWAYSONTOP;
         }
         else
         {
             flags = (flags & ~CHF_BEHINDSHEPHERD);
-            followinfo = (std::min<int>(UINT8_MAX, dist) << 8) | std::min<int>(UINT8_MAX, eagerness);
+            legacy_followinfo = (std::min<int>(UINT8_MAX, dist) << 8) | std::min<int>(UINT8_MAX, eagerness);
         }
     }
 

Engine/ac/character.cpp

@@ -516,37 +516,27 @@ void Character_FollowCharacter(CharacterInfo *chaa, CharacterInfo *tofollow, int
         debug_script_log("%s: Stop following other character", chaa->scrname);
     }
 
-    if ((chaa->following >= 0) &&
-        (chaa->followinfo == FOLLOW_ALWAYSONTOP))
+    CharacterExtras *chex = &charextra[chaa->index_id];
+    if ((chex->following >= 0) &&
+        (chex->follow_dist == FOLLOW_ALWAYSONTOP))
     {
             // if this character was following always-on-top, its baseline will
             // have been changed, so release it.
             chaa->baseline = -1;
     }
 
-    if (tofollow == nullptr)
-    {
-        chaa->set_following(-1, 0, 0, false);
-    }
-    else if (distaway == FOLLOW_ALWAYSONTOP)
-    {
-        chaa->set_following(tofollow->index_id, FOLLOW_ALWAYSONTOP, 0, (eagerness == 1));
-    }
-    else
-    {
-        chaa->set_following(tofollow->index_id, distaway, eagerness, false);
-    }
+    chex->SetFollowing(chaa, tofollow ? tofollow->index_id : -1, distaway, eagerness, (eagerness == 1));
 
     if (chaa->animating & CHANIM_REPEAT)
         debug_script_warn("Warning: FollowCharacter called but the sheep is currently animating looped. It may never start to follow.");
 }
 
 CharacterInfo* Character_GetFollowing(CharacterInfo* chaa)
 {
-    if (chaa->following < 0)
+    if (charextra[chaa->index_id].following < 0)
         return nullptr;
 
-    return &game.chars[chaa->following];
+    return &game.chars[charextra[chaa->index_id].following];
 }
 
 int Character_IsCollidingWithChar(CharacterInfo *char1, CharacterInfo *char2) {

Engine/ac/characterextras.cpp

@@ -35,6 +35,25 @@ void CharacterExtras::CheckViewFrame(CharacterInfo *chi)
     ::CheckViewFrame(chi->view, chi->loop, chi->frame, GetFrameSoundVolume(chi));
 }
 
+void CharacterExtras::SetFollowing(CharacterInfo *chi, int follow_who, int distance, int eagerness, bool sort_behind)
+{
+    if (follow_who < 0)
+    {
+        following = -1;
+        follow_dist = 0;
+        follow_eagerness = 0;
+    }
+    else
+    {
+        following = follow_who;
+        follow_dist = distance;
+        follow_eagerness = (distance == FOLLOW_ALWAYSONTOP) ? 0 : eagerness;
+    }
+
+    // Set Character's following flags, and legacy fields, for backwards compatibility
+    chi->set_following(following, follow_dist, follow_eagerness, sort_behind);
+}
+
 void CharacterExtras::ReadFromSavegame(Stream *in, CharacterSvgVersion save_ver)
 {
     in->ReadArrayOfInt16(invorder, MAX_INVORDER);
@@ -59,6 +78,12 @@ void CharacterExtras::ReadFromSavegame(Stream *in, CharacterSvgVersion save_ver)
         in->ReadInt8(); // reserved to fill int32
         in->ReadInt8();
     }
+    if (save_ver >= kCharSvgVersion_36205)
+    {
+        following = in->ReadInt32();
+        follow_dist = in->ReadInt32();
+        follow_eagerness = in->ReadInt32();
+    }
 }
 
 void CharacterExtras::WriteToSavegame(Stream *out) const
@@ -78,8 +103,13 @@ void CharacterExtras::WriteToSavegame(Stream *out) const
     out->WriteInt8(process_idle_this_time);
     out->WriteInt8(slow_move_counter);
     out->WriteInt16(animwait);
+    // kCharSvgVersion_36025
     out->WriteInt8(static_cast<uint8_t>(anim_volume));
     out->WriteInt8(static_cast<uint8_t>(cur_anim_volume));
     out->WriteInt8(0); // reserved to fill int32
     out->WriteInt8(0);
+    // kCharSvgVersion_36205
+    out->WriteInt32(following);
+    out->WriteInt32(follow_dist);
+    out->WriteInt32(follow_eagerness);
 }

Engine/ac/characterextras.h

@@ -56,20 +56,25 @@ struct CharacterExtras
     short animwait = 0;
     int   anim_volume = 100; // default animation volume (relative factor)
     int   cur_anim_volume = 100; // current animation sound volume (relative factor)
+    int   following = -1; // whom do we follow (character id)
+    int   follow_dist = 0; // follow distance, in pixels
+    int   follow_eagerness = 0; // follow reaction
 
     // Following fields are deriatives of the above (calculated from these
     // and other factors), and hence are not serialized.
     //
     // zoom factor of sprite offsets, fixed at 100 in backwards compatible mode
     int   zoom_offs = 100;
 
-    int GetEffectiveY(CharacterInfo *chi) const; // return Y - Z
-
+    // Get visual Y position, which is calculated as Y - Z (scaled)
+    int GetEffectiveY(CharacterInfo *chi) const; 
     // Calculate wanted frame sound volume based on multiple factors
     int GetFrameSoundVolume(CharacterInfo *chi) const;
     // Process the current animation frame for the character:
     // play linked sounds, and so forth.
     void CheckViewFrame(CharacterInfo *chi);
+    // Setups following another character (follow_who)
+    void SetFollowing(CharacterInfo *chi, int follow_who, int distance = 0, int eagerness = 0, bool sort_behind = false);
 
     // Read character extra data from saves.
     void ReadFromSavegame(Common::Stream *in, CharacterSvgVersion save_ver);

Engine/ac/characterinfo_engine.cpp

@@ -124,7 +124,7 @@ void UpdateCharacterMoveAndAnim(CharacterInfo *chi, CharacterExtras *chex, std::
 
 void UpdateFollowingExactlyCharacter(CharacterInfo *chi)
 {
-    const auto &following = game.chars[chi->following];
+    const auto &following = game.chars[charextra[chi->index_id].following];
     chi->x = following.x;
     chi->y = following.y;
     chi->z = following.z;
@@ -363,9 +363,10 @@ bool UpdateCharacterAnimating(CharacterInfo *chi, CharacterExtras *chex, int &do
 
 void UpdateCharacterFollower(CharacterInfo *chi, std::vector<int> &followingAsSheep, int &doing_nothing)
 {
-    const int following = chi->following;
-    const int distaway = chi->get_follow_distance();
-    const int eagerness = chi->get_follow_eagerness();
+    const CharacterExtras *chex = &charextra[chi->index_id];
+    const int following = chex->following;
+    const int distaway  = chex->follow_dist;
+    const int eagerness = chex->follow_eagerness;
 
     if ((following >= 0) && (distaway == FOLLOW_ALWAYSONTOP)) {
       // an always-on-top follow

Engine/ac/dynobj/cc_character.cpp

@@ -82,8 +82,8 @@ int16_t CCCharacter::ReadInt16(const void *address, intptr_t offset)
     switch (offset)
     {
     // +9 int32 = 36
-    case 36: return ci->following;
-    case 38: return ci->followinfo;
+    case 36: return ci->legacy_following;
+    case 38: return ci->legacy_followinfo;
     // 40 +1 int32 = 44
     case 44: return ci->idletime;
     case 46: return ci->idleleft;

Engine/ac/room.cpp

@@ -88,6 +88,7 @@ extern int in_new_room, new_room_was;  // 1 in new room, 2 first time in new roo
 extern ScriptHotspot scrHotspot[MAX_ROOM_HOTSPOTS];
 extern int in_leaves_screen;
 extern CharacterInfo*playerchar;
+extern std::vector<CharacterExtras> charextra;
 extern int starting_room;
 extern unsigned int loopcounter;
 extern IDriverDependantBitmap* roomBackgroundBmp;
@@ -719,14 +720,14 @@ void load_new_room(int newnum, CharacterInfo*forchar) {
         // if a following character is still waiting to come into the
         // previous room, force it out so that the timer resets
         for (int ff = 0; ff < game.numcharacters; ff++) {
-            if ((game.chars[ff].following >= 0) && (game.chars[ff].room < 0)) {
-                if ((game.chars[ff].following == game.playercharacter) &&
+            if ((charextra[ff].following >= 0) && (game.chars[ff].room < 0)) {
+                if ((charextra[ff].following == game.playercharacter) &&
                     (forchar->prevroom == newnum))
                     // the player went back to the previous room, so make sure
                     // the following character is still there
                     game.chars[ff].room = newnum;
                 else
-                    game.chars[ff].room = game.chars[game.chars[ff].following].room;
+                    game.chars[ff].room = game.chars[charextra[ff].following].room;
             }
         }
 
@@ -947,11 +948,12 @@ void new_room(int newnum,CharacterInfo*forchar) {
     newnum = in_leaves_screen;
     in_leaves_screen = -1;
 
-    if ((playerchar->following >= 0) &&
-        (game.chars[playerchar->following].room != newnum)) {
+    CharacterExtras *player_ex = &charextra[playerchar->index_id];
+    if ((player_ex->following >= 0) &&
+        (game.chars[player_ex->following].room != newnum)) {
             // the player character is following another character,
             // who is not in the new room. therefore, abort the follow
-            playerchar->set_following(-1);
+            player_ex->SetFollowing(playerchar, -1);
     }
 
     // change rooms

Engine/game/savegame_components.cpp

@@ -674,8 +674,15 @@ HSaveError ReadCharacters(Stream *in, int32_t cmp_ver, soff_t cmp_size, const Pr
 
     for (uint32_t i = 0; i < characters_read; ++i)
     {
-        game.chars[i].ReadFromSavegame(in, game.chars2[i], static_cast<CharacterSvgVersion>(cmp_ver));
-        charextra[i].ReadFromSavegame(in, static_cast<CharacterSvgVersion>(cmp_ver));
+        auto &chi = game.chars[i];
+        auto &chex = charextra[i];
+        chi.ReadFromSavegame(in, game.chars2[i], static_cast<CharacterSvgVersion>(cmp_ver));
+        chex.ReadFromSavegame(in, static_cast<CharacterSvgVersion>(cmp_ver));
+        // re-assign legacy following params (for old saves)
+        if (cmp_ver < kCharSvgVersion_36205)
+        {
+            charextra[i].SetFollowing(&chi, chi.legacy_following, chi.get_follow_distance(), chi.get_follow_eagerness(), chi.get_follow_sort_behind());
+        }
         Properties::ReadValues(play.charProps[i], in);
         if (loaded_game_file_version <= kGameVersion_272)
             ReadTimesRun272(*game.intrChar[i], in);
@@ -1703,7 +1710,7 @@ ComponentHandler ComponentHandlers[] =
     },
     {
         "Characters",
-        kCharSvgVersion_36115,
+        kCharSvgVersion_36205,
         kCharSvgVersion_350, // skip pre-alpha 3.5.0 ver
         kSaveCmp_Characters,
         WriteCharacters,

Engine/main/engine.cpp

@@ -660,7 +660,7 @@ void engine_init_game_settings()
     for (ee=0;ee<game.numcharacters;ee++) {
         memset(&game.chars[ee].inv[0],0,MAX_INV*sizeof(short));
         game.chars[ee].activeinv=-1;
-        game.chars[ee].set_following(-1, 10, 97, false);
+        game.chars[ee].set_following(-1, 10, 97, false); // some legacy def values, not sure if necessary
         if (loaded_game_file_version < kGameVersion_360)
             game.chars[ee].idletime=20; // default to 20 seconds
         game.chars[ee].idleleft=game.chars[ee].idletime;

Engine/main/game_run.cpp

@@ -530,7 +530,7 @@ bool run_service_key_controls(KeyInput &out_key)
                 game.chars[chd].scrname, game.chars[chd].view + 1, game.chars[chd].loop, game.chars[chd].frame,
                 game.chars[chd].x, game.chars[chd].y, game.chars[chd].z,
                 game.chars[chd].idleview, game.chars[chd].idletime, game.chars[chd].idleleft,
-                game.chars[chd].walking, game.chars[chd].animating, game.chars[chd].following,
+                game.chars[chd].walking, game.chars[chd].animating, charextra[chd].following,
                 game.chars[chd].flags, game.chars[chd].wait, charextra[chd].zoom);
         }
         DisplayMB(buffer.GetCStr());