Struct TessBuilder

pub struct TessBuilder<'a, B, V, I = (), W = (), S = Interleaved>
where
    B: ?Sized,
    V: TessVertexData<S>,
    W: TessVertexData<S>,
    S: ?Sized,
{ /* private fields */ }

Tess builder object.

This type allows to create Tess via a builder pattern. You have several flavors of possible vertex storages, as well as data encoding, described below.

Vertex storage

Interleaved

You can pass around interleaved vertices and indices. Those are encoded in Vec<T>. You typically want to use this when you already have the vertices and/or indices allocated somewhere, as the interface will use the input vector as a source of truth for lengths.

Deinterleaved

This is the same as interleaved data in terms of interface, but the T type is interpreted a bit differently. Here, the encoding is (Vec<Field0>, Vec<Field1>, …), where Field0, Field1 etc. are all the ordered fieds in T. This logic is hidden behind Vec<DeinterleavedData>.

That representation allows field-based operations on Tess, while it would be impossible with the interleaved version (you would need to get all the fields at once, since you would work on T directly and each of its fields).

Data encoding

• Vectors: you can pass vectors as input data for both vertices and indices. Those will be interpreted differently based on the vertex storage you chose for vertices / instances. For indices, there is no difference.
• Disabled: disabling means that no data will be passed to the GPU. You can disable independently vertex data and/or index data by using the unit () type.

Indexed vertex sets

It is possible to index the geometry via the use of indices. Indices are stored in contiguous regions of memory (Vec<T>), where T satisfies TessIndex. When using an indexed tessellation, the meaning of its attributes slightly changes. First, the vertices are not used as input source for the vertex stream. In order to provide vertices that will go through the vertex stream, the indices reference the vertex set to provide the order in which they should appear in the stream.

When rendering with a TessView, the number of vertices to render must be provided or inferred based on the Tess the view was made from. That number will refer to either the vertex set or index set, depending on the kind of tessellation. Asking to render a Tess with 3 vertices will pick 3 vertices from the vertex set for direct tessellations and 3 indices to index the vertex set for indexed tessellations.

Primitive mode

By default, a TessBuilder will build points. Each vertex in the vertex stream will be independently rendered from the others, resulting in a point cloud. This logic is encoded with Mode::Point. You can change how vertices are interpreted by changing the Mode.

Parametricity

• B is the backend type
• V is the vertex type.
• I is the index type.
• W is the vertex instance type.
• S is the storage type.

Implementations

impl<'a, B, V, I, W, S> TessBuilder<'a, B, V, I, W, S>

where B: ?Sized, V: TessVertexData<S>, I: TessIndex, W: TessVertexData<S>, S: ?Sized,

pub fn set_mode(self, mode: Mode) -> Self

Set the Mode to connect vertices.

Calling that function twice replaces the previously set value.

pub fn set_render_vertex_nb(self, vert_nb: usize) -> Self

Set the default number of vertices to render.

Calling that function twice replaces the previously set value. This method changes the number of vertices to pick:

• From the vertex set for regular geometries.
• From the index set, using the picked indices to reference the vertex set.

pub fn set_render_instance_nb(self, inst_nb: usize) -> Self

Set the default number of instances to render.

Calling that function twice replaces the previously set value.

pub fn set_primitive_restart_index(self, restart_index: I) -> Self

Set the primitive restart index.

Calling that function twice replaces the previously set value.

impl<'a, B, V, I, W, S> TessBuilder<'a, B, V, I, W, S>

where B: ?Sized, V: TessVertexData<S>, I: TessIndex, W: TessVertexData<S>, S: ?Sized,

pub fn new<C>(ctx: &'a mut C) -> Self

where C: GraphicsContext<Backend = B>,

Create a new default TessBuilder.

Notes

Feel free to use the GraphicsContext::new_tess method for a simpler method.

impl<'a, B, V, W, S> TessBuilder<'a, B, V, (), W, S>

where B: ?Sized, V: TessVertexData<S>, W: TessVertexData<S>, S: ?Sized,

pub fn set_indices<I, X>(self, indices: X) -> TessBuilder<'a, B, V, I, W, S>

where X: Into<Vec<I>>,

Add indices to be bundled in the Tess.

Every time you call that function, the set of indices is replaced by the one you provided. The type of expected indices is ruled by the II type variable you chose.

impl<'a, B, I, W> TessBuilder<'a, B, (), I, W, Interleaved>

where B: ?Sized, I: TessIndex, W: TessVertexData<Interleaved>,

pub fn set_vertices<V, X>( self, vertices: X, ) -> TessBuilder<'a, B, V, I, W, Interleaved>

where X: Into<Vec<V>>, V: TessVertexData<Interleaved, Data = Vec<V>>,

Add vertices to be bundled in the Tess.

Every time you call that function, the set of vertices is replaced by the one you provided.

impl<'a, B, I, V> TessBuilder<'a, B, V, I, (), Interleaved>

where B: ?Sized, I: TessIndex, V: TessVertexData<Interleaved>,

pub fn set_instances<W, X>( self, instances: X, ) -> TessBuilder<'a, B, V, I, W, Interleaved>

where X: Into<Vec<W>>, W: TessVertexData<Interleaved, Data = Vec<W>>,

Add instances to be bundled in the Tess.

Every time you call that function, the set of instances is replaced by the one you provided.

impl<'a, B, V, I, W> TessBuilder<'a, B, V, I, W, Deinterleaved>

where B: ?Sized, V: TessVertexData<Deinterleaved, Data = Vec<DeinterleavedData>>, I: TessIndex, W: TessVertexData<Deinterleaved, Data = Vec<DeinterleavedData>>,

pub fn set_attributes<A, X>(self, attributes: X) -> Self

where X: Into<Vec<A>>, V: Deinterleave<A>,

Add vertices to be bundled in the Tess.

Every time you call that function, the set of vertices is replaced by the one you provided.

pub fn set_instance_attributes<A, X>(self, attributes: X) -> Self

where X: Into<Vec<A>>, W: Deinterleave<A>,

Add instances to be bundled in the Tess.

Every time you call that function, the set of instances is replaced by the one you provided.

impl<'a, B, V, I, W, S> TessBuilder<'a, B, V, I, W, S>

where B: ?Sized + TessBackend<V, I, W, S>, V: TessVertexData<S>, I: TessIndex, W: TessVertexData<S>,

pub fn build(self) -> Result<Tess<B, V, I, W, S>, TessError>

Build a Tess if the TessBuilder has enough data and is in a valid state. What is needed is backend-dependent but most of the time, you will want to:

• Set a Mode.
• Give vertex data and optionally indices, or give none of them but only a number of vertices (attributeless objects).
• If you provide vertex data by submitting several sets with TessBuilder::set_attributes and/or TessBuilder::set_instances, do not forget that you must submit sets with the same size. Otherwise, the GPU will not know what values use for missing attributes in vertices.

Trait Implementations

impl<'a, B, V, I: Debug, W, S> Debug for TessBuilder<'a, B, V, I, W, S>

where B: ?Sized + Debug, V: TessVertexData<S> + Debug, W: TessVertexData<S> + Debug, S: ?Sized + Debug, V::Data: Debug, W::Data: Debug,

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

Formats the value using the given formatter.