Handle optional arguments for warp commands, add WARP_ID_NONE

include/constants/maps.h

@@ -15,4 +15,16 @@
 #define MAP_GROUP_SPECIAL_MONS_1 MAP_GROUP(METEOR_FALLS_1F_1R)
 #define MAP_GROUP_SPECIAL_MONS_2 MAP_GROUP(SAFARI_ZONE_NORTHWEST)
 
+// IDs for dynamic warps. Both are used in the dest_warp_id field for warp events, but they
+// are never read in practice. A dest_map of MAP_NONE is used to indicate that a
+// dynamic warp should be used, at which point the warp id is ignored. It can be passed to
+// SetDynamicWarp/SetDynamicWarpWithCoords as the first argument, but this argument is unused.
+// As only one dynamic warp is saved at a time there's no need to distinguish between them.
+#define WARP_ID_SECRET_BASE 0x7E
+#define WARP_ID_DYNAMIC     0x7F
+
+// Used to indicate an invalid warp id, for dummy warps or when a warp should
+// use the given coordinates rather than the coordinates of a target warp.
+#define WARP_ID_NONE (-1)
+
 #endif  // GUARD_CONSTANTS_MAPS_H

include/global.h

@@ -10,6 +10,7 @@
 #include "constants/vars.h"
 #include "constants/species.h"
 #include "constants/berry.h"
+#include "constants/maps.h"
 
 // Prevent cross-jump optimization.
 #define BLOCK_CROSS_JUMP asm("");