rendy-mesh
Helper crate for gfx-hal
to create and use meshes with vertex semantics.
Vertex semantics
Vertex formats usually have semantics attached to field names. A common example is for a vertex to be composed of a position, normal, color and texture coordinate field. This crate provides traits and types to have semantics explicitly defined for a vertex at the type level.
Position
, Normal
, TexCoord
etc. are attributes that have unambiguous semantics.
Users can define their own attribute types by implementing the Attribute
trait.
While the attribute type on its own is a trivial vertex format (with single attribute), complex vertex formats are created by composing attribute types.
The WithAttribute
trait allows to get formatting info for individual attributes defined in a vertex format.
The Query
trait allows to get formatting info for several attributes at once.
VertexFormat
queried from vertex formats can be used to build graphics pipelines and bind required vertex buffers from mesh to command buffer.
To define a custom vertex format type, the AsVertexFormat
trait must be implemented providing a VertexFormat
associated constant.
WithAttribute
can be implemented also for all attributes and the VertexFormat
associated constant in AsVertexFormat
can be defined more clearly by utilizing the WithAttribute
implementation. Query
is automatically implemented.
Mesh
Mesh
is a collection of vertex buffers and optionally an index buffer together with vertex formats of the buffers and index type. Also there is a primitive type specified which defines how vertices form primitives (lines, triangles etc).
To create instances of Mesh
you need to use MeshBuilder
.
- Fill
MeshBuilder
with typed vertex data. - Provide the index data.
- Set the primitive type (Triangles list by default).
- Call
MeshBuilder::build
. It usesFactory
fromgfx-render
to create buffers and upload data.
Here is your fresh new Mesh
. Or an Error
from gfx-render
.
To bind vertex buffers to a command buffer use Mesh::bind
with a sorted array of VertexFormat
s (the same that was used to setup the graphics pipeline).