trainer_see through CheckPathBetweenTrainerAndPlayer

src/trainer_see.c

@@ -0,0 +1,174 @@
+#include "global.h"
+#include "battle_setup.h"
+#include "field_player_avatar.h"
+#include "event_object_movement.h"
+#include "quest_log.h"
+#include "constants/battle_setup.h"
+
+static bool8 CheckTrainer(u8 objectEventId);
+static u8 GetTrainerApproachDistance(struct ObjectEvent * objectEvent);
+static u8 GetTrainerApproachDistanceSouth(struct ObjectEvent * objectEvent, s16 range, s16 x, s16 y);
+static u8 GetTrainerApproachDistanceNorth(struct ObjectEvent * objectEvent, s16 range, s16 x, s16 y);
+static u8 GetTrainerApproachDistanceWest(struct ObjectEvent * objectEvent, s16 range, s16 x, s16 y);
+static u8 GetTrainerApproachDistanceEast(struct ObjectEvent * objectEvent, s16 range, s16 x, s16 y);
+static u8 CheckPathBetweenTrainerAndPlayer(struct ObjectEvent * objectEvent, u8 approachDistance, u8 facingDirection);
+void sub_8081E68(struct ObjectEvent * objectEvent, u8 approachDistance);
+
+const u16 gUnknown_83C6AC8[] = INCBIN_U16("graphics/object_events/emoticons.4bpp");
+
+u8 (*const sDirectionalApproachDistanceFuncs[])(struct ObjectEvent *, s16 range, s16 x, s16 y) = {
+    GetTrainerApproachDistanceSouth,
+    GetTrainerApproachDistanceNorth,
+    GetTrainerApproachDistanceWest,
+    GetTrainerApproachDistanceEast
+};
+
+bool8 CheckForTrainersWantingBattle(void)
+{
+    u8 i;
+    if (sub_8111C2C() == TRUE)
+        return FALSE;
+
+    for (i = 0; i < OBJECT_EVENTS_COUNT; i++)
+    {
+        if (gObjectEvents[i].active
+         && (
+             gObjectEvents[i].trainerType == 1
+          || gObjectEvents[i].trainerType == 3
+         )
+         && CheckTrainer(i)
+      )
+            return TRUE;
+    }
+    return FALSE;
+}
+
+static bool8 CheckTrainer(u8 objectEventId)
+{
+    const u8 *script = GetObjectEventScriptPointerByObjectEventId(objectEventId);
+    u8 approachDistance;
+    if (GetTrainerFlagFromScriptPointer(script))
+        return FALSE;
+    approachDistance = GetTrainerApproachDistance(&gObjectEvents[objectEventId]);
+    if (approachDistance != 0)
+    {
+        if (script[1] == TRAINER_BATTLE_DOUBLE && GetMonsStateToDoubles())
+            return FALSE;
+        ConfigureAndSetUpOneTrainerBattle(objectEventId, script);
+        sub_8081E68(&gObjectEvents[objectEventId], approachDistance - 1);
+        return TRUE;
+    }
+    return FALSE;
+}
+
+static u8 GetTrainerApproachDistance(struct ObjectEvent *trainerObj)
+{
+    s16 x, y;
+    u8 i;
+    u8 approachDistance;
+
+    PlayerGetDestCoords(&x, &y);
+    if (trainerObj->trainerType == 1)  // can only see in one direction
+    {
+        approachDistance = sDirectionalApproachDistanceFuncs[trainerObj->facingDirection - 1](trainerObj, trainerObj->trainerRange_berryTreeId, x, y);
+        return CheckPathBetweenTrainerAndPlayer(trainerObj, approachDistance, trainerObj->facingDirection);
+    }
+    else  // can see in all directions
+    {
+        for (i = 0; i < 4; i++)
+        {
+            approachDistance = sDirectionalApproachDistanceFuncs[i](trainerObj, trainerObj->trainerRange_berryTreeId, x, y);
+            if (CheckPathBetweenTrainerAndPlayer(trainerObj, approachDistance, i + 1)) // directions are 1-4 instead of 0-3. south north west east
+                return approachDistance;
+        }
+    }
+
+    return 0;
+}
+
+// Returns how far south the player is from trainer. 0 if out of trainer's sight.
+static u8 GetTrainerApproachDistanceSouth(struct ObjectEvent *trainerObj, s16 range, s16 x, s16 y)
+{
+    if (trainerObj->currentCoords.x == x
+        && y > trainerObj->currentCoords.y
+        && y <= trainerObj->currentCoords.y + range)
+    {
+        if (range > 3 && sub_805DF30() == OBJECT_EVENTS_COUNT)
+            return 0;
+        return (y - trainerObj->currentCoords.y);
+    }
+    else
+        return 0;
+}
+
+// Returns how far north the player is from trainer. 0 if out of trainer's sight.
+static u8 GetTrainerApproachDistanceNorth(struct ObjectEvent *trainerObj, s16 range, s16 x, s16 y)
+{
+    if (trainerObj->currentCoords.x == x
+        && y < trainerObj->currentCoords.y
+        && y >= trainerObj->currentCoords.y - range)
+        return (trainerObj->currentCoords.y - y);
+    else
+        return 0;
+}
+
+// Returns how far west the player is from trainer. 0 if out of trainer's sight.
+static u8 GetTrainerApproachDistanceWest(struct ObjectEvent *trainerObj, s16 range, s16 x, s16 y)
+{
+    if (trainerObj->currentCoords.y == y
+        && x < trainerObj->currentCoords.x
+        && x >= trainerObj->currentCoords.x - range)
+        return (trainerObj->currentCoords.x - x);
+    else
+        return 0;
+}
+
+// Returns how far east the player is from trainer. 0 if out of trainer's sight.
+static u8 GetTrainerApproachDistanceEast(struct ObjectEvent *trainerObj, s16 range, s16 x, s16 y)
+{
+    if (trainerObj->currentCoords.y == y
+        && x > trainerObj->currentCoords.x
+        && x <= trainerObj->currentCoords.x + range)
+        return (x - trainerObj->currentCoords.x);
+    else
+        return 0;
+}
+
+#define COLLISION_MASK (~1)
+
+static u8 CheckPathBetweenTrainerAndPlayer(struct ObjectEvent *trainerObj, u8 approachDistance, u8 direction)
+{
+    s16 x, y;
+    u8 unk19_temp;
+    u8 unk19b_temp;
+    u8 i;
+    u8 collision;
+
+    if (approachDistance == 0)
+        return 0;
+
+    x = trainerObj->currentCoords.x;
+    y = trainerObj->currentCoords.y;
+
+    for (i = 0; i <= approachDistance - 1; i++, MoveCoords(direction, &x, &y))
+    {
+        collision = GetCollisionFlagsAtCoords(trainerObj, x, y, direction);
+        if (collision != 0 && (collision & COLLISION_MASK))
+            return 0;
+    }
+
+    // preserve mapobj_unk_19 before clearing.
+    unk19_temp = trainerObj->range.as_nybbles.x;
+    unk19b_temp = trainerObj->range.as_nybbles.y;
+    trainerObj->range.as_nybbles.x = 0;
+    trainerObj->range.as_nybbles.y = 0;
+
+    collision = GetCollisionAtCoords(trainerObj, x, y, direction);
+
+    trainerObj->range.as_nybbles.x = unk19_temp;
+    trainerObj->range.as_nybbles.y = unk19b_temp;
+    if (collision == 4)
+        return approachDistance;
+
+    return 0;
+}