Enum wgpu::VertexStepMode

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#[repr(C)]
pub enum VertexStepMode { Vertex = 0, Instance = 1, }
Expand description

Whether a vertex buffer is indexed by vertex or by instance.

Consider a call to RenderPass::draw like this:

render_pass.draw(vertices, instances)

where vertices is a Range<u32> of vertex indices, and instances is a Range<u32> of instance indices.

For this call, wgpu invokes the vertex shader entry point once for every possible (v, i) pair, where v is drawn from vertices and i is drawn from instances. These invocations may happen in any order, and will usually run in parallel.

Each vertex buffer has a step mode, established by the step_mode field of its VertexBufferLayout, given when the pipeline was created. Buffers whose step mode is Vertex use v as the index into their contents, whereas buffers whose step mode is Instance use i. The indicated buffer element then contributes zero or more attribute values for the (v, i) vertex shader invocation to use, based on the VertexBufferLayout’s attributes list.

You can visualize the results from all these vertex shader invocations as a matrix with a row for each i from instances, and with a column for each v from vertices. In one sense, v and i are symmetrical: both are used to index vertex buffers and provide attribute values. But the key difference between v and i is that line and triangle primitives are built from the values of each row, along which i is constant and v varies, not the columns.

An indexed draw call works similarly:

render_pass.draw_indexed(indices, base_vertex, instances)

The only difference is that v values are drawn from the contents of the index buffer—specifically, the subrange of the index buffer given by indices—instead of simply being sequential integers, as they are in a draw call.

A non-instanced call, where instances is 0..1, is simply a matrix with only one row.

Corresponds to WebGPU GPUVertexStepMode.

Variants§

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Vertex = 0

Vertex data is advanced every vertex.

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Instance = 1

Vertex data is advanced every instance.

Trait Implementations§

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impl Clone for VertexStepMode

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fn clone(&self) -> VertexStepMode

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for VertexStepMode

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

Formats the value using the given formatter. Read more
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impl Default for VertexStepMode

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fn default() -> VertexStepMode

Returns the “default value” for a type. Read more
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impl Hash for VertexStepMode

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fn hash<__H>(&self, state: &mut __H)
where __H: Hasher,

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for VertexStepMode

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

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

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impl Eq for VertexStepMode

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impl StructuralEq for VertexStepMode

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impl StructuralPartialEq for VertexStepMode

Auto Trait Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> Downcast<T> for T

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fn downcast(&self) -> &T

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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> Upcast<T> for T

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fn upcast(&self) -> Option<&T>

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where T: Sync,