collision_ellipse( x1, y1, x2, y2, obj, prec, notme );
| Argument | Description |
|---|---|
| x1 | The x coordinate of the left side of the ellipse to check. |
| y1 | The y coordinate of the top side of the ellipse to check. |
| x2 | The x coordinate of the right side of the ellipse to check. |
| y2 | The y coordinate of the bottom side of the ellipse to check. |
| obj | The object to check for instance collisions. |
| prec | Whether the check is based on pixel-perfect collisions (true = slow) or its bounding box in general (false = fast). |
| notme | Whether the calling instance, if relevant, should be excluded (true) or not (false). |
Returns: Instance id or noone
Collision_ellipse uses the first four arguments (x1,y1,x2,y2) to
define the width and height of an ellipse within the current room
and then checks to see if any object that is defined by the
"obj" argument is in collision with that area. This collision can
be checked as precise or not, and you may also choose to check for
the instance running the code itself or not. Consider this
image:
Here, the instance in the middle is using a collision ellipse to
check for ball objects. Now, the blue ones do not have a
precise bounding box and as you can see, even if the sprite is not
actually touching the ellipse, the collision can still happen (even
if you set the precise option in the function to true) as the
bounding box of that sprite over-laps the elliptical area defined
by collision_circle. On the other hand, the green balls will only
be considered in collision if the actual sprite over-laps the
defined ellipse. Remember, for precise collisions to be considered
both the object sprite and the collision function must have
precise marked as on. It should also be noted that the return value
of the function can be the id of any one of the instances
considered to be in collision.
if collision_ellipse(50, 50, 200, 100, obj_Player,
false, true)
{
instance_create(obj_Player.x, obj_Player.y,
obj_Splash);
}
This will check an elliptical zone within the bounds of 50x, 50y and 200x, 100y for the object "obj_Player". If there is a collision with that object, then it will create an instance of "obj_Splash" at the x/y coordinates of obj_Player.