Struct Fixed

pub struct Fixed { /* private fields */ }

The fixed timestep game clock following virtual time.

A specialization of the Time structure. For method documentation, see Time<Fixed>.

It is automatically inserted as a resource by TimePlugin and updated based on Time<Virtual>. The fixed clock is automatically set as the generic Time resource during FixedUpdate schedule processing.

The fixed timestep clock advances in fixed-size increments, which is extremely useful for writing logic (like physics) that should have consistent behavior, regardless of framerate.

The default timestep() is 64 hertz, or 15625 microseconds. This value was chosen because using 60 hertz has the potential for a pathological interaction with the monitor refresh rate where the game alternates between running two fixed timesteps and zero fixed timesteps per frame (for example when running two fixed timesteps takes longer than a frame). Additionally, the value is a power of two which losslessly converts into f32 and f64.

To run a system on a fixed timestep, add it to one of the FixedMain schedules, most commonly FixedUpdate.

This schedule is run a number of times between PreUpdate and Update according to the accumulated overstep() time divided by the timestep(). This means the schedule may run 0, 1 or more times during a single update (which typically corresponds to a rendered frame).

Time<Fixed> and the generic Time resource will report a delta() equal to timestep() and always grow elapsed() by one timestep() per iteration.

The fixed timestep clock follows the Time<Virtual> clock, which means it is affected by pause(), set_relative_speed() and set_max_delta() from virtual time. If the virtual clock is paused, the FixedUpdate schedule will not run. It is guaranteed that the elapsed() time in Time<Fixed> is always between the previous elapsed() and the current elapsed() value in Time<Virtual>, so the values are compatible.

Changing the timestep size while the game is running should not normally be done, as having a regular interval is the point of this schedule, but it may be necessary for effects like “bullet-time” if the normal granularity of the fixed timestep is too big for the slowed down time. In this case, set_timestep() and be called to set a new value. The new value will be used immediately for the next run of the FixedUpdate schedule, meaning that it will affect the delta() value for the very next FixedUpdate, even if it is still during the same frame. Any overstep() present in the accumulator will be processed according to the new timestep() value.

Trait Implementations

impl Clone for Fixed

fn clone(&self) -> Fixed

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Fixed

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

Formats the value using the given formatter.

impl Default for Fixed

fn default() -> Self

Returns the “default value” for a type.

impl FromReflect for Fixed

where Self: Any + Send + Sync, Duration: FromReflect + TypePath + RegisterForReflection,

fn from_reflect(reflect: &dyn Reflect) -> Option<Self>

Constructs a concrete instance of Self from a reflected value.

fn take_from_reflect( reflect: Box<dyn Reflect>, ) -> Result<Self, Box<dyn Reflect>>

Attempts to downcast the given value to Self using, constructing the value using from_reflect if that fails.

impl GetTypeRegistration for Fixed

where Self: Any + Send + Sync, Duration: FromReflect + TypePath + RegisterForReflection,

fn get_type_registration() -> TypeRegistration

Returns the default TypeRegistration for this type.

fn register_type_dependencies(registry: &mut TypeRegistry)

Registers other types needed by this type.

impl Reflect for Fixed

where Self: Any + Send + Sync, Duration: FromReflect + TypePath + RegisterForReflection,

fn get_represented_type_info(&self) -> Option<&'static TypeInfo>

Returns the TypeInfo of the type represented by this value.

fn into_any(self: Box<Self>) -> Box<dyn Any>

Returns the value as a Box<dyn Any>.

fn as_any(&self) -> &dyn Any

Returns the value as a &dyn Any.

fn as_any_mut(&mut self) -> &mut dyn Any

Returns the value as a &mut dyn Any.

fn into_reflect(self: Box<Self>) -> Box<dyn Reflect>

Casts this type to a boxed reflected value.

fn as_reflect(&self) -> &dyn Reflect

Casts this type to a reflected value.

fn as_reflect_mut(&mut self) -> &mut dyn Reflect

Casts this type to a mutable reflected value.

fn clone_value(&self) -> Box<dyn Reflect>

Clones the value as a Reflect trait object.

fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>>

Performs a type-checked assignment of a reflected value to this value.

fn try_apply(&mut self, value: &dyn Reflect) -> Result<(), ApplyError>

Tries to apply a reflected value to this value.

fn reflect_kind(&self) -> ReflectKind

Returns a zero-sized enumeration of “kinds” of type.

fn reflect_ref(&self) -> ReflectRef<'_>

Returns an immutable enumeration of “kinds” of type.

fn reflect_mut(&mut self) -> ReflectMut<'_>

Returns a mutable enumeration of “kinds” of type.

fn reflect_owned(self: Box<Self>) -> ReflectOwned

Returns an owned enumeration of “kinds” of type.

fn reflect_partial_eq(&self, value: &dyn Reflect) -> Option<bool>

Returns a “partial equality” comparison result.

fn apply(&mut self, value: &(dyn Reflect + 'static))

Applies a reflected value to this value.

fn reflect_hash(&self) -> Option<u64>

Returns a hash of the value (which includes the type).

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

Debug formatter for the value.

fn serializable(&self) -> Option<Serializable<'_>>

Returns a serializable version of the value.

fn is_dynamic(&self) -> bool

Indicates whether or not this type is a dynamic type.

impl Struct for Fixed

where Self: Any + Send + Sync, Duration: FromReflect + TypePath + RegisterForReflection,

fn field(&self, name: &str) -> Option<&dyn Reflect>

Returns a reference to the value of the field named name as a &dyn Reflect.

fn field_mut(&mut self, name: &str) -> Option<&mut dyn Reflect>

Returns a mutable reference to the value of the field named name as a &mut dyn Reflect.

fn field_at(&self, index: usize) -> Option<&dyn Reflect>

Returns a reference to the value of the field with index index as a &dyn Reflect.

fn field_at_mut(&mut self, index: usize) -> Option<&mut dyn Reflect>

Returns a mutable reference to the value of the field with index index as a &mut dyn Reflect.

fn name_at(&self, index: usize) -> Option<&str>

Returns the name of the field with index index.

fn field_len(&self) -> usize

Returns the number of fields in the struct.

fn iter_fields(&self) -> FieldIter<'_>

Returns an iterator over the values of the reflectable fields for this struct.

fn clone_dynamic(&self) -> DynamicStruct

Clones the struct into a DynamicStruct.

impl TypePath for Fixed

where Self: Any + Send + Sync,

fn type_path() -> &'static str

Returns the fully qualified path of the underlying type.

fn short_type_path() -> &'static str

Returns a short, pretty-print enabled path to the type.

fn type_ident() -> Option<&'static str>

Returns the name of the type, or None if it is anonymous.

fn crate_name() -> Option<&'static str>

Returns the name of the crate the type is in, or None if it is anonymous.

fn module_path() -> Option<&'static str>

Returns the path to the module the type is in, or None if it is anonymous.

impl Typed for Fixed

where Self: Any + Send + Sync, Duration: FromReflect + TypePath + RegisterForReflection,

fn type_info() -> &'static TypeInfo

Returns the compile-time info for the underlying type.

impl Copy for Fixed