Trait collider::HbProfile [−] [src]

pub trait HbProfile: Copy {
    fn id(&self) -> HbId;

    fn can_interact(&self, other: &Self) -> bool;

    fn cell_width() -> f64;

    fn padding() -> f64;

    fn group(&self) -> Option<HbGroup> { ... }

    fn interact_groups(&self) -> &'static [HbGroup] { ... }
}

A trait that holds metadata for describing a hitbox.

A user of Collider will need to implement an HbProfile that best suites their needs in a game. The most basic HbProfile will just contain an integer ID for the hitbox, but a user may define additional metadata for identfying the hitbox and describing interactivity. An HbProfile must implement the Copy trait and should not take up much memory.

Required Methods

A unique identifier for the hitbox.

Trying to have multiple hitboxes with the same id to a Collider instance simultaneously will result in a panic.

Returns true if the pair of hitboxes should be checked for collisions.

This method should be commutative. This method should be consistent with group and interact_groups, although possibly more restrictive.

The width of the cells used in the Collider grid.

To reduce the number of overlaps that are tested, hitboxes are placed in a sparse grid structure behind the scenes. cell_width is the width of the cells used in that grid. If your game has a similar grid concept, then it is usually a good choice to use the same cell width as that grid. Otherwise, a good choice is to use a width that is slightly larger than most of the hitboxes.

The minimum distance before two hitboxes are considered separated.

Collider generates both Collide and Separate events. However, due to numerical error, it is important that two hitboxes be a certain small distance apart from each other after a collision before they are considered separated. Otherwise, false separation events may occur if, for example, a sprite runs into a wall and stops, still touching the wall. padding is used to describe what this minimum separation distance is. This should typically be something that is not visible to the user, perhaps a fraction of a "pixel."

Another restriction introduced by padding is that hitboxes are not allowed to have a width or height smaller than padding.

Provided Methods

Returns the group id associated with the hitbox. Default is Some(0).

If None is returned, then no collisions will be reported for this hitbox at all.

Returns a list of groups that this hitbox can interact with. Default is [0].

Using large lists of groups may be inefficient.

Implementors