Struct DoubleBuffer

pub struct DoubleBuffer<T> { /* private fields */ }

Implementations

impl<T> DoubleBuffer<T>

An implementation of the Double Buffer pattern from ‘Game Programming Patterns’ by Robert Nystrom.

In a simulation, you often have to do a lot of processing to prepare the next “frame”, but if you’re iterating through the current-state data while mutating it, things can slip. The Double Buffer design pattern solves this by keeping two copies of the simulation state (or any variable): the “current” (or previous) state which is immutable, and the “next” (or future) state which is being prepared. When a turn of the simulation is completed, you simply switch the buffers.

Unlike other implementations on crates.io, this one wraps both buffers in std::cell::RefCell so that it is possible to borrow one buffer as mutable at the same time the other is borrowed as immutable – a typical use case is to iterate over objects in the current state and write updated versions of them to the next state.

pub fn new(current: T, next: T) -> Self

pub fn current(&self) -> Ref<'_, T>

Get an immutable reference to the current-state buffer.

pub fn next(&self) -> RefMut<'_, T>

Get a mutable reference to the next-state buffer.

pub fn next_immut(&self) -> Ref<'_, T>

Get an immutable reference to the next-state buffer.

pub fn switch(&mut self)

Switch the “current” and “next” buffers.