Struct gravitas::Gravity

pub struct Gravity { /* fields omitted */ }

a position under the influence of gravity (or any other constant acceleration), as defined by Newton's 2nd Law: F = ma.

Newton's 2nd law, F = ma, integrates to x' = x + v * t + 0.5 * a * t * t, which is what this simulation uses to compute a position.

This simulation is nice for objects that are falling, or have to overcome gravity in some way.

• gravity combined with a spring simulation to make bouncy dialog boxes: Gravitas JavaScript bouncy dialogs.
• gravity used to make a lock screen, which must be dragged upwards to unlock: Gravitas JavaScript lock screen.

Methods

impl Gravity

pub fn new(a: f32) -> Gravity

Create a new gravity siulation with the given acceleration. A value of 500 * 9.8 (so 500px corresponds to 1 meter) is normally a good starting point.

pub fn set(&mut self, x: f32, v: f32)

Set the initial position and velocity (in pixels per second) of the gravity simulation.

Trait Implementations

impl Clone for Gravity

fn clone(&self) -> Gravity

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Gravity

impl Simulation for Gravity

fn x(&self, time: f32) -> f32

Return the position for the given time (in seconds).

fn dx(&self, time: f32) -> f32

Return the velocity for the given time (in seconds).

fn is_done(&self, time: f32) -> bool

Return true if the simulation has reached a final position at the given time (in seconds).