Saved flags and bytes

To remember something about the player's progress, such as whether they opened a door or how many times they talked to an NPC, use a saved flag or byte. A flag is true or false, and a byte holds a number from -128 to 127.

Kind	How many	Lasts
Game flags, GF_	2048	For the whole save file
Game bytes, GB_	512	For the whole save file
Area flags, AF_	256	Until the player enters a different area
Area bytes, AB_	16	Until the player enters a different area

Use an area flag or byte for something the player can redo after they leave, such as a puzzle that resets. For EVT variables that aren't saved, see Variables.

Story progress

GB_StoryProgress records how far through the story the player is, as a value from the STORY_ list in enums.h, such as STORY_CH1_SPOKE_WITH_MERLON. The values are in story order, so an EVT script can check whether the player has reached a point:

IfGe(GB_StoryProgress, STORY_CH1_SPOKE_WITH_MERLON)
    Call(SpeakToPlayer, NPC_PARTNER, ANIM_Goompa_Talk, ANIM_Goompa_Idle, 0, MSG_CH0_001C)
EndIf

To move the story on, set it with Set(GB_StoryProgress, STORY_CH1_DEFEATED_KOOPA_BROS). To add a point in the story, add a value to the STORY_ list.

When you test a scene, the debug menu's Set Story Byte option lets you jump to any point in the story.

Adding a game flag or byte

Game flags are listed in saved_flag_names.h, and game bytes in saved_byte_names.h. Each unused one has a name such as GF_Unused_7F0. To add your own, rename an unused one:

GF_KMR02_OpenedGate                         = GameFlag(0x7F0),

Name it after the map it belongs to and what it records, like the game's own flags. Then use the name in EVT scripts:

IfEq(GF_KMR02_OpenedGate, false)
    Set(GF_KMR02_OpenedGate, true)
EndIf

Once players have saves of your mod, don't change the number in an existing flag's GameFlag() or byte's GameByte(), because their saves store each flag by its number.

Adding an area flag or byte

Area flags and bytes are listed in the area's header, such as world/area/kmr/kmr.h. Add a name with AreaFlag() or AreaByte() and a number that no other name in that area uses:

enum AreaFlagsKMR {
    AF_KMR02_GatePuzzleSolved                = AreaFlag(0x08),
};

Each area has its own 256 area flags and 16 area bytes, so two areas can use the same number for different things.

Reading and writing flags in C

evt_get_variable and evt_set_variable work with saved flags and bytes when you pass nullptr as the EVT script:

if (evt_get_variable(nullptr, GF_KMR02_OpenedGate)) {
    evt_set_variable(nullptr, GB_StoryProgress, STORY_CH1_DEFEATED_KOOPA_BROS);
}