rooms: use flip status flag for finding rooms

This introduces a flip status flag on rooms so that we can avoid
yielding rooms that are not in the correct state when finding one by
position.

Resolves #2362.
Resolves #2370.

docs/tr1/CHANGELOG.md

@@ -20,6 +20,8 @@
 - changed the `/kill` command with no arguments to look for enemies within 5 tiles (#2297)
 - fixed blood spawning on Lara from gunshots using incorrect positioning data (#2253)
 - fixed ghost meshes appearing near statics in custom levels (#2310)
+- fixed photo mode switching to the wrong flipmap rooms at times (#2362)
+- fixed the teleporting command sometimes putting Lara in invalid flipmap rooms (#2370)
 - fixed the upside-down camera fix to no longer limit Lara's vision (#2276, regression from 4.2)
 - fixed being unable to load some old custom levels that contain certain (invalid) floor data (#2114, regression from 4.3)
 - fixed a desync in the Lost Valley demo if responsive swim cancellation was enabled (#2113, regression from 4.6)

docs/tr2/CHANGELOG.md

@@ -22,6 +22,8 @@
 - fixed blood spawning on Lara from gunshots using incorrect positioning data (#2253)
 - fixed ghost meshes appearing near statics in custom levels (#2310)
 - fixed potential memory corruption when reading a custom level with more than 512 sprite textures (#2338)
+- fixed photo mode switching to the wrong flipmap rooms at times (#2362)
+- fixed the teleporting command sometimes putting Lara in invalid flipmap rooms (#2370)
 - fixed Lara activating triggers one frame too early (#2205, regression from 0.7)
 - fixed savegame incompatibility with OG (#2271, regression from 0.8)
 - fixed stopwatch showing wrong UI in some circumstances (#2221, regression from 0.8)

src/libtrx/game/rooms/common.c

@@ -96,6 +96,20 @@ static const int16_t *M_ReadTrigger(
     return data;
 }
 
+void Room_InitialiseFlipStatus(void)
+{
+    for (int32_t i = 0; i < Room_GetTotalCount(); i++) {
+        ROOM *const room = Room_Get(i);
+        if (room->flipped_room == -1) {
+            room->flip_status = RFS_NONE;
+        } else if (room->flip_status != RFS_FLIPPED) {
+            ROOM *const flipped_room = Room_Get(room->flipped_room);
+            room->flip_status = RFS_UNFLIPPED;
+            flipped_room->flip_status = RFS_FLIPPED;
+        }
+    }
+}
+
 void Room_ParseFloorData(const int16_t *floor_data)
 {
     for (int32_t i = 0; i < Room_GetTotalCount(); i++) {
@@ -200,6 +214,9 @@ int32_t Room_FindByPos(const int32_t x, const int32_t y, const int32_t z)
 {
     for (int32_t i = 0; i < Room_GetTotalCount(); i++) {
         const ROOM *const room = Room_Get(i);
+        if (room->flip_status == RFS_FLIPPED) {
+            continue;
+        }
         const int32_t x1 = room->pos.x + WALL_L;
         const int32_t x2 = room->pos.x + (room->size.x - 1) * WALL_L;
         const int32_t y1 = room->max_ceiling;

src/libtrx/include/libtrx/game/rooms/common.h

@@ -6,6 +6,7 @@
 extern int32_t Room_GetTotalCount(void);
 extern ROOM *Room_Get(int32_t room_num);
 
+void Room_InitialiseFlipStatus(void);
 extern void Room_FlipMap(void);
 extern bool Room_GetFlipStatus(void);
 

src/libtrx/include/libtrx/game/rooms/enum.h

@@ -16,6 +16,12 @@ typedef enum {
     RLM_NUMBER_OF = 4,
 } ROOM_LIGHT_MODE;
 
+typedef enum {
+    RFS_NONE = 0,
+    RFS_UNFLIPPED = 1,
+    RFS_FLIPPED = 2,
+} ROOM_FLIP_STATUS;
+
 typedef enum {
     FT_FLOOR = 0,
     FT_DOOR = 1,

src/libtrx/include/libtrx/game/rooms/types.h

@@ -130,5 +130,6 @@ typedef struct {
     int16_t item_num;
     int16_t effect_num;
     int16_t flipped_room;
+    ROOM_FLIP_STATUS flip_status;
     uint16_t flags;
 } ROOM;

src/tr1/game/level.c

@@ -257,6 +257,7 @@ static void M_LoadRooms(VFILE *file)
         r->effect_num = NO_EFFECT;
     }
 
+    Room_InitialiseFlipStatus();
     Level_ReadFloorData(file);
 
     Benchmark_End(benchmark, NULL);

src/tr1/game/room.c

@@ -582,6 +582,8 @@ void Room_FlipMap(void)
 
         r->flipped_room = flipped->flipped_room;
         flipped->flipped_room = -1;
+        r->flip_status = RFS_UNFLIPPED;
+        flipped->flip_status = RFS_FLIPPED;
 
         // XXX: is this really necessary given the assignments above?
         r->item_num = flipped->item_num;

src/tr2/game/level.c

@@ -230,6 +230,7 @@ static void M_LoadRooms(VFILE *const file)
         r->effect_num = NO_EFFECT;
     }
 
+    Room_InitialiseFlipStatus();
     Level_ReadFloorData(file);
 
 finish:

src/tr2/game/room.c

@@ -773,6 +773,8 @@ void Room_FlipMap(void)
 
         r->flipped_room = flipped->flipped_room;
         flipped->flipped_room = NO_ROOM_NEG;
+        r->flip_status = RFS_UNFLIPPED;
+        flipped->flip_status = RFS_FLIPPED;
 
         // TODO: is this really necessary given the assignments above?
         r->item_num = flipped->item_num;