static bool WouldCollide(const Game_Character& self, const Game_Character& other, bool self_conflict) {
if (self.GetThrough() || other.GetThrough()) {
return false;
}
if (self.IsFlying() || other.IsFlying()) {
return false;
}
if (!self.IsActive() || !other.IsActive()) {
return false;
}
if (self.GetType() == Game_Character::Event
&& other.GetType() == Game_Character::Event
&& (self.IsOverlapForbidden() || other.IsOverlapForbidden())) {
return true;
}
if (other.GetLayer() == RPG::EventPage::Layers_same && self_conflict) {
return true;
}
if (self.GetLayer() == other.GetLayer()) {
return true;
}
return false;
}
/**
* Checks whether a collision occurs between self and other if self
* moves from (x,y) to (new_x, new_y) in direction d.
*
* If other is a tile event, also indicates if the player can use it
* as a "bridge" to step across without hitting the underlying tile
* layer.
*/
static CollisionResult TestCollisionDuringMove(
int x,
int y,
int new_x,
int new_y,
int d,
const Game_Character& self,
const Game_Event& other
) {
if (!other.GetActive()) {
return NoCollision;
}
if (&self == &other) {
return NoCollision;
}
if (other.GetThrough()) {
return NoCollision;
}
if (!other.IsInPosition(x, y) && !other.IsInPosition(new_x, new_y)) {
return NoCollision;
}
if (&self != Main_Data::game_player.get()) {
if (other.IsInPosition(new_x, new_y) && (self.IsOverlapForbidden() || other.IsOverlapForbidden())) {
return Collision;
}
}
if (other.IsInPosition(new_x, new_y) && self.GetLayer() == other.GetLayer()) {
return Collision;
}
if (other.GetLayer() == RPG::EventPage::Layers_below) {
int tile_id = other.GetTileId();
if ((passages_up[tile_id] & Passable::Above) != 0) {
return NoCollision;
}
if (other.IsInPosition(x,y) && (passages_up[tile_id] & DirToMask(d)) != 0) {
return CanStepOffCurrentTile;
}
else if (other.IsInPosition(new_x, new_y) && (passages_up[tile_id] & DirToMask(Game_Character::ReverseDir(d))) != 0) {
return CanStepOntoNewTile;
} else {
return Collision;
}
}
return NoCollision;
}
bool Game_Map::MakeWay(int x, int y, int d, const Game_Character& self, bool force_through) {
int new_x = RoundX(x + (d == Game_Character::Right ? 1 : d == Game_Character::Left ? -1 : 0));
int new_y = RoundY(y + (d == Game_Character::Down ? 1 : d == Game_Character::Up ? -1 : 0));
if (!Game_Map::IsValid(new_x, new_y))
return false;
if (self.GetThrough() || force_through) return true;
// A character can move to a position with an impassable tile by
// standing on top of an event below it. These flags track whether
// we stepped off an event and therefore don't need to check the
// passability of the tile layer below.
bool stepped_off_event = false;
bool stepped_onto_event = false;
for (Game_Event& other : GetEvents()) {
CollisionResult result = TestCollisionDuringMove(x, y, new_x, new_y, d, self, other);
if (result == Collision) {
// Try updating the offending event to give it a chance to move out of the
// way and recheck.
other.UpdateParallel();
if (TestCollisionDuringMove(x, y, new_x, new_y, d, self, other) == Collision) {
return false;
}
}
else if (result == CanStepOffCurrentTile) {
stepped_off_event = true;
} else if (result == CanStepOntoNewTile) {
stepped_onto_event = true;
}
}
if (vehicles[0]->IsInPosition(new_x, new_y) || vehicles[1]->IsInPosition(new_x, new_y)) {
return false;
}
if (Main_Data::game_player->IsInPosition(new_x, new_y)
&& !Main_Data::game_player->GetThrough()
&& self.GetLayer() == RPG::EventPage::Layers_same) {
// Update the Player to see if they'll move and recheck.
Main_Data::game_player->Update(!first_frame);
if (Main_Data::game_player->IsInPosition(new_x, new_y)) {
return false;
}
}
return
(stepped_off_event || IsPassableTile(DirToMask(d), x + y * GetWidth()))
&& (stepped_onto_event || IsPassableTile(DirToMask(Game_Character::ReverseDir(d)), new_x + new_y * GetWidth()));
}
bool Game_Map::MakeWay(const Game_Character& self, int x, int y) {
// Moving to same tile (used for jumps) always succeeds
if (x == self.GetX() && y == self.GetY()) {
return true;
}
if (!self.IsJumping() && x != self.GetX() && y != self.GetY()) {
// Handle diagonal stepping.
// Must be able to step on at least one of the 2 adjacent tiles and also the target tile.
// Verified behavior: Always checks vertical first, only checks horizontal if vertical fails.
bool vertical_ok = MakeWay(self, self.GetX(), y);
if (!vertical_ok) {
bool horizontal_ok = MakeWay(self, x, self.GetY());
if (!horizontal_ok) {
return false;
}
}
}
// Infer directions before we do any rounding.
const auto bit_from = GetPassableMask(self.GetX(), self.GetY(), x, y);
const auto bit_to = GetPassableMask(x, y, self.GetX(), self.GetY());
// Now round for looping maps.
x = Game_Map::RoundX(x);
y = Game_Map::RoundY(y);
// Note, even for diagonal, if the tile is invalid we still check vertical/horizontal first!
if (!Game_Map::IsValid(x, y)) {
return false;
}
if (self.GetThrough()) {
return true;
}
const auto vehicle_type = static_cast<Game_Vehicle::Type>(self.GetVehicleType());
bool self_conflict = false;
if (!self.IsJumping()) {
// Check for self conflict.
// If this event has a tile graphic and the tile itself has passage blocked in the direction
// we want to move, flag it as "self conflicting" for use later.
if (self.GetLayer() == RPG::EventPage::Layers_below && self.GetTileId() != 0) {
int tile_id = self.GetTileId();
if ((passages_up[tile_id] & bit_from) == 0) {
self_conflict = true;
}
}
if (vehicle_type == Game_Vehicle::None) {
// Check that we are allowed to step off of the current tile.
// Note: Vehicles can always step off a tile.
if (!IsPassableTile(&self, bit_from, self.GetX(), self.GetY())) {
return false;
}
}
}
if (vehicle_type != Game_Vehicle::Airship) {
// Check for collision with events on the target tile.
for (auto& other: GetEvents()) {
if (MakeWayCollideEvent(x, y, self, other, self_conflict)) {
return false;
}
}
auto& player = Main_Data::game_player;
if (player->GetVehicleType() == Game_Vehicle::None) {
if (MakeWayCollideEvent(x, y, self, *Main_Data::game_player, self_conflict)) {
return false;
}
}
for (auto vid: { Game_Vehicle::Boat, Game_Vehicle::Ship}) {
auto& other = vehicles[vid - 1];
if (other->IsInCurrentMap()) {
if (MakeWayCollideEvent(x, y, self, *other, self_conflict)) {
return false;
}
}
}
auto& airship = vehicles[Game_Vehicle::Airship - 1];
if (airship->IsInCurrentMap() && self.GetType() != Game_Character::Player) {
if (MakeWayCollideEvent(x, y, self, *airship, self_conflict)) {
return false;
}
}
}
int bit = bit_to;
if (self.IsJumping()) {
bit = Passable::Down | Passable::Up | Passable::Left | Passable::Right;
}
return IsPassableTile(&self, bit, x, y);
}