Describes an individual
Vertex. In other words a collection of attributes that can be read
from a vertex shader.
At this stage, the vertex is in a "raw" format. For example a
[f32; 4] can match both a
vec4 or a
float. The way the things are bound depends on the shader.
fn member(name: &str) -> Option<VertexMemberInfo>
Returns the characteristics of a vertex member by its name.