/**
* \brief Tests whether a point collides with the ground of the map.
*
* The ground is the terrain of the point. It is defined by the tiles and
* by the presence of entities that may change it
* (like dynamic tiles and destructible items).
*
* This method also returns true if the point is outside the map.
*
* \param layer Layer of the point.
* \param x X of the point in pixels.
* \param y Y of the point in pixels.
* \param entity_to_check The entity to check (used to decide what grounds are
* considered as obstacle).
* \param [out] found_diagonal_wall \c true if the ground under this point was
* a diagonal wall, unchanged otherwise.
* Your algorithm may decide to check more points if there is a diagonal wall.
* \return \c true if this point is on an obstacle.
*/
bool Map::test_collision_with_ground(
int layer,
int x,
int y,
const Entity& entity_to_check,
bool& found_diagonal_wall) const {
bool on_obstacle = false;
int x_in_tile, y_in_tile;
// If the point is outside the map, this is an obstacle.
if (test_collision_with_border(x, y)) {
return true;
}
// Get the ground property under this point.
Ground ground = get_ground(layer, x, y);
switch (ground) {
case Ground::EMPTY:
case Ground::TRAVERSABLE:
case Ground::GRASS:
case Ground::ICE:
// The square is not an obstacle.
on_obstacle = false;
break;
case Ground::WALL:
// The square is entirely an obstacle.
on_obstacle = true;
break;
case Ground::WALL_TOP_RIGHT:
case Ground::WALL_TOP_RIGHT_WATER:
// The upper right half of the square is an obstacle
// so we have to test the position of the point in the square.
x_in_tile = x & 7;
y_in_tile = y & 7;
on_obstacle = y_in_tile <= x_in_tile;
found_diagonal_wall = true;
break;
case Ground::WALL_TOP_LEFT:
case Ground::WALL_TOP_LEFT_WATER:
// Same thing.
x_in_tile = x & 7;
y_in_tile = y & 7;
on_obstacle = y_in_tile <= 7 - x_in_tile;
found_diagonal_wall = true;
break;
case Ground::WALL_BOTTOM_LEFT:
case Ground::WALL_BOTTOM_LEFT_WATER:
x_in_tile = x & 7;
y_in_tile = y & 7;
on_obstacle = y_in_tile >= x_in_tile;
found_diagonal_wall = true;
break;
case Ground::WALL_BOTTOM_RIGHT:
case Ground::WALL_BOTTOM_RIGHT_WATER:
x_in_tile = x & 7;
y_in_tile = y & 7;
on_obstacle = y_in_tile >= 7 - x_in_tile;
found_diagonal_wall = true;
break;
case Ground::LOW_WALL:
case Ground::SHALLOW_WATER:
case Ground::DEEP_WATER:
case Ground::HOLE:
case Ground::LAVA:
case Ground::PRICKLE:
case Ground::LADDER:
on_obstacle = entity_to_check.is_ground_obstacle(ground);
break;
}
return on_obstacle;
}
/**
* \brief Returns the ground at the specified point.
*
* Static tiles and dynamic entities are all taken into account here.
*
* \param layer Layer of the point.
* \param xy Coordinate of the point.
* \return The ground at this place.
*/
Ground Map::get_ground(Layer layer, const Rectangle& xy) const {
return get_ground(layer, xy.get_x(), xy.get_y());
}
/**
* \brief Returns the ground at the specified point.
*
* Static tiles and dynamic entities are all taken into account here.
*
* \param layer Layer of the point.
* \param xy Coordinate of the point.
* \return The ground at this place.
*/
Ground Map::get_ground(int layer, const Point& xy) const {
return get_ground(layer, xy.x, xy.y);
}
