PrimitiveStreams implement the Functor class, which provides the fmap method that you can use to manipulate those streams. This corresponds to writing and using vertex shaders, but in a much more modular way. You may for instance apply fmap several times in a sequence, effectively creating complex shaders.

Instances are also provided for the Monoid class, so several streams (of the same type) can be concatenated. The order is preserved, meaning that the primitives in stream a in a mappend b will be drawn before the primitives in b.

All atomic values except textures in vertex streams uses the Vertex type constructor. Composite types are created by composing the atomic Vertex types, rather than wrapping the composite type in the Vertex type constructors.

Vertex instances for are provided for most of Prelude's numerical classes. Since Eq, Ord and Show are prerequisites for these classes, instances are provided for them too, even though their methods all will generate errors if used (except min and max). Use the instances of EqB, OrdB and IfB from the Boolean package if you want to compare Vertex values. Hyperbolic trigonometrical functions aren't provided either.

Rewrite rule specializations are provided for the Vec package functions norm, normalize, dot and cross on vectors of Vertex Float, so the use of these functions (and others from that package that is defined in terms of them) are highly encouraged.