Consolidate the projects

[kvark]

A bit of history:

• gfx-rs started as a single project, having everything (renderer, device, macros, even windowing stuff) under one repository in different modules
• macros were moved out
• eventually, associated types got supported by Rust, and we were able to move the device out
• examples followed the suit
• we ended up following Piston organization style and created a repository per project. More and more showed up, mostly bearing just a bit of function.

Currently we have 10 projects closely related to gfx-rs, and this number doesn't include gfx_scene or genmesh. This confuses newcomers and throttles our ability to do cross-project changes.

Unexpectedly, a new style of organization showed up to be effective in gfx_scene and claymore: gather all relevant projects under one roof and use both path = and version = in the dependencies. As it turned out, this scheme has proper crates dependencies and publishing doesn't require any temporary changes. I propose to follow this scheme for gfx-rs as well to get:

• easier branching (especially for new major versions)
• easier pull requests with no/less dependencies
• faster and more secure builds (single cargo test does everything)
• less confusion for the users (gfx-rs organization would have 4 projects instead of 13)
• single issue database

Paint me red and stuff, but I don't see the downsides. Note that we can do it right now without breaking anything, since users now depend on crates.io. Here is how I see the consolidated repo:

gfx/ # does it make sense to keep it gfx-rs?
  examples/ # gfx_examples/bin
  src/
    aux/
       gl/ # gfx_gl
    backend/
      gl/ # gfx_device_gl
      dummy/ # gfx_device_dummy
      vulkan/ # gfx_device_vulkan
    core/ # gfx-rs
    draw_state/ # arguable, lets hear @bvssvni
    window/
      glfw/ # gfx_window_glfw
      glutin/ # gfx_window_glutin
    main.rs # empty, just to depend on all the crates
  info/ # additional documentation, like what we have in gfx-rs/wiki
  .travis.yml # there can be only one

Summoning @gfx-rs/developers for discussion!

[ghost]

This is similar to how we started.

I don't have a problem with this, but I want to preserve the commit history of all our projects. Not sure how to do with when merging git repos but there is bound to be a stackoverflow for it.

[kvark]

@csherratt Good point. gfx_device_gl in particular has some history. On the other hand, most of the changes reflect the associated gfx-rs PRs.

[fkaa]

Not a @gfx-rs/developers but i think it sounds great! I didn't exactly have a good time making a PR for 5 separate gfx repos at the same time...

[kvark]

@fkaa fixed!

[kvark]

Small issue: gfx_gl uses git submodules, which would need to be moved into the whole repo. I don't like this idea, so leaving gfx_gl aside for now.

[kvark]

Another issue: tests for dependent projects are not started automatically by cargo.test. We may need to pull all the tests into the root crate.

[brendanzab]

Don't have a problem with this, but I echo the comments about preserving git history.

[brendanzab]

I wounder if this should be a medium or hard, given the difficulty of the repo merger.

[kvark]

@bjz thanks for coming in!

Since we use 'hard' for the most difficult issues (like, implement DX backend), this one deserves a vague average rating.

I'll redo the PR with preserved history, not sure how painful it's going to be though. If you want to try it yourself, please give me a short nod so that we don't duplicate this exciting work.

[kvark]

Heads up - SO answer seems to be working fine, I'm half-way through the change.

[ghost]

🎉 Wonderful @kvark

[bvssvni]

Nice!

[kvark]

@bvssvni I was thinking if you would consider the unification of some degree for Piston repositories. Their diversity and number often seemed to be a source of confusion.