Struct double_buffer::DoubleBuffer

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

Encapsulates a piece of state that can be modified and we want all outside code to see the edit as a single atomic change.

Trait implementations

If trait use an immutable reference (AsRef<T>, Deref<T>, Borrow<T>…) give access to the current value and mutable references (AsMut<T>, DerefMut<T>, BorrowMut<T>…) give access to the next value.

Swapping

There are three ways to swap:

1. DoubleBuffer::swap() - when swapping, the next value will have the previous current value.
2. DoubleBuffer::swap_with_clone() - when swapping, the next value will keep same and will be cloned to the current value.
3. DoubleBuffer::swap_with_default() - like DoubleBuffer::swap() but the next value will be set to the default value of the type.

Note that for the third way, the type must implement Default.

You can read about the two ways how the buffers are swapped in “Game Programming Patterns” by Robert Nystrom.

Examples

The following example shows how the buffer is swapped with the three ways:

let mut buffer: DoubleBuffer<[u8; 32]> = DoubleBuffer::default();
print!("{:?}", buffer); // DoubleBuffer { current: [0, ...], next: [0, ...] }

buffer[0] = 1;
print!("{:?}", buffer); // DoubleBuffer { current: [0, ...], next: [1, ...] }

buffer.swap();
print!("{:?}", buffer); // DoubleBuffer { current: [1, ...], next: [0, ...] }

buffer[0] = 2;
print!("{:?}", buffer); // DoubleBuffer { current: [1, ...], next: [2, ...] }

buffer.swap_with_clone();
print!("{:?}", buffer); // DoubleBuffer { current: [2, ...], next: [2, ...] }

buffer[0] = 3;
print!("{:?}", buffer); // DoubleBuffer { current: [2, ...], next: [3, ...] }

buffer.swap_with_default();
print!("{:?}", buffer); // DoubleBuffer { current: [3, ...], next: [0, ...] }

Implementations

impl<T> DoubleBuffer<T>

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

pub fn swap(&mut self)

Swaps the current and next values, then writes will be over the previous current value.

impl<T: Clone> DoubleBuffer<T>

pub fn swap_with_clone(&mut self)

Swaps buffers cloning the next value to the current value, then writes will continue over the same next value.

impl<T: Default> DoubleBuffer<T>

pub fn swap_with_default(&mut self)

Swaps buffers and sets the next value to the default value of the type, then writes will be over the default value.

Trait Implementations

impl<T> AsMut<T> for DoubleBuffer<T>

fn as_mut(&mut self) -> &mut T

Converts this type into a mutable reference of the (usually inferred) input type.

impl<T> AsRef<T> for DoubleBuffer<T>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<T> Borrow<T> for DoubleBuffer<T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T> BorrowMut<T> for DoubleBuffer<T>

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value.

impl<T: Debug> Debug for DoubleBuffer<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for DoubleBuffer<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Deref for DoubleBuffer<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> DerefMut for DoubleBuffer<T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<T: Ord> Ord for DoubleBuffer<T>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq<DoubleBuffer<T>> for DoubleBuffer<T>

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

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialEq> PartialEq<T> for DoubleBuffer<T>

fn eq(&self, other: &T) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd> PartialOrd<DoubleBuffer<T>> for DoubleBuffer<T>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: PartialOrd> PartialOrd<T> for DoubleBuffer<T>

fn partial_cmp(&self, other: &T) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Eq> Eq for DoubleBuffer<T>