Roadmap wiki

Hello GPUWeb,

I'd like to discuss the first draft of the Roadmap document:
https://github.com/gpuweb/gpuweb/wiki/Roadmap

First of all, big thanks to Myles for starting the effort!!!

Several consensus items raised at least one of my eyebrows:

> Consensus: MVP will only allow one instance of a queue object
> Consensus: Consecutive render passes don’t inherit state
> Consensus: In general, include the union of all 3 platform API’s pipeline
state
> Consensus: Renderpass information is not included (Vulkan backends will
create dummy renderpasses)

And this one can raise a Google's eyebrow, given that they proposed to hide
the concept of descriptor pools/maps:
> Consensus: Generally, use Vulkan’s binding model: A 3-layered hierarchy:
Descriptors, a set of descriptors, and a (single) collection of sets.

Not necessarily saying these are incorrect (I might have just missed the
consensus), but it would be great to link to a particular spot in the notes
where the points are agreed upon.

Clarifications I think we can add safely:

> Open Question: D3D has to keep samplers separately from all other
resources

Another open question: D3D allows only one of each descriptor heap type to
be bound at any particular point in the command list.

> Open Question: Aligned to what?

I think we have an answer.
For buffer copy operations, buffer offsets need to be aligned to 512 bytes
in D3D12 and to the optimal alignment (as specified by the device
capabilities) in Vulkan. Buffer row pitches should be correspondingly
aligned to 256 bytes in D3D12 and the optimal pitch alignment in Vulkan.
Also see https://github.com/gpuweb/gpuweb/issues/28

Regards,
Dzmitry