With this function you can check a position for a collision with all instances of an object (or a tile map) using the collision mask of the instance that runs the code.
When you use this you are effectively asking GameMaker to move the instance to the new position, check for a collision, then move back and tell you what collisions were found. This will work for precise collisions, but only if both the instance and the instances of the object being checked for have precise collision masks selected, otherwise only bounding box collisions are applied.
In addition to objects and instances, the function also accepts:
Passing an array allows you to check for collisions against multiple objects and/or Tile Maps in one call.
You supply a DS list too, so the id values of any instances (or tile maps) that are colliding with the calling instance will be added to the end of the given list. You can clear the list before calling this function so that it only contains results from this function call. You also have the option to order the list based on the distance from the origin of the instance doing the checking to the origin of the instances found to be in collision.
The function returns the number of instances / tile maps found, or 0 if none are found.
See: Collisions
instance_place_list(x, y, obj, list, ordered);
| Argument | Type | Description |
|---|---|---|
| x | Real | The x position to check for instances. |
| y | Real | The y position to check for instances. |
| obj | Object Asset or Object Instance or Tile Map Element ID or Array | An object, instance, tile map ID, keywords all/other, or array containing these items |
| list | DS List | The DS list to use to store the IDs of colliding instances. |
| ordered | Boolean | Whether the list should be ordered by distance (true) or not (false). |
Real (The number of instances / tile maps found to be in collision)
var _list = ds_list_create();
var _num = instance_place_list(x, y, obj_Enemy, _list, false);
if _num > 0
{
for (var i = 0; i < _num; ++i;)
{
instance_destroy(_list[| i]);
}
}
ds_list_destroy(_list);
The above code will check for a collision with all instances found at the calling instances position. These will be added to a DS list, which is then looped through to destroy each of the instances in collision.