nannou v0.9 - Vulkan graphics, simpler event API and much more

[mitchmindtree]

This is easily the biggest update for nannou so far!

OpenGL -> Vulkan

The switch from OpenGL to Vulkan for cross-platform graphics is the main story here. You can find more details at #208 and #216, but the primary reasons for switching to Vulkan are:

• Gaining support for compiling and running languages other than GLSL (e.g. RLSL, HLSL) on the GPU via Vulkan's low-level SPIR-V representation.
• Access to finer-grained control over the GPU for more thorough optimisation if necessary.
• No longer having to deal with OpenGL bugs resulting from inconsistent implementations across different devices and versions.
• Switching to a more modern, future-proof, cross-platform graphics standard.

Both High-level and Low-level Access

While the existing high-level graphics APIs should behave almost exactly the same (apart from smoother graphics and slightly better performance), this PR also allows for much lower level access to the graphics stack than was previously available. In other words, nannou now allows for fully custom graphics pipeline creation, access to each window's unique swapchain, custom vulkan instance creation, custom device selection and loads more. To demonstrate this low level access, @JoshuaBatty and I have started a new series of vk_*.rs examples in the examples/vulkan/ directory. These demonstrate how to work with basic geometry, images, 3D, first-person cameras, compute shaders and more. We'll continue adding to these over time - requests are very welcome!

GLSL

Note that GLSL is still well supported so you can still reach into your existing bag of shader tricks! Note however that currently only the most recent versions of GLSL are supported, so you may need to update older versions. Funnily enough, this might make it easier to run GLSL 450 code on macOS as I believe support for more recent versions of OpenGL and GLSL from Apple have been lacking.

MacOS

For folks wondering about how macOS is supported, nannou uses vulkano under the hood which links to MoltenVK on macOS for translating Vulkan to Apple's Metal API. We're hoping that by the time this is merged, @freesig's work on automating the MoltenVK installation process at build time will have landed. In theory this means that you should be able to run cargo build like normal and everything should Just Work™ (you might have to restart your terminal), though don't be surprised if there are hiccups as this is all still very new.

Tradeoffs

All that said, this change will mean that nannou may no longer be compatible on some older systems that don't yet have Vulkan support. Nannou aims to foster the next generation of creative coding and with our small team's limited capacity this unfortunately means we must draw a line in the sand at some point. If you're curious about the level of support for Vulkan on your system's GPU you can search for it here to find detailed reports. If you're not sure what GPU you have or it's not listed in that database, the site will allow you to download the tool for generating your own report.

If nannou was working for you in 0.8 but stopped in 0.9 we would love for you to leave an issue and let us know. We'll do our best to address each issue, though keep in mind that our ability will be limited in cases where Vulkan driver support is lacking.

Simpler Event API

One glaring issue with nannou's current event API is the way that user's are expected to handle events via the event function. While the event type is thorough and allows for accessing loads of hardware, application and window events, handling the Event type itself could be quite verbose and confronting for new users who might be unfamiliar with the fancy pattern matching required.

This update allows for using functions to handle events in a way that will be much more familiar to users coming from Processing, OF and Cinder and reduces the amount of language-learning users have to go through before they can start being creative.

For a closer look at these changes check out #221 and in particular the changes to the examples in the diff. The new all_functions.rs example demonstrates all of the new event functions that may be registered with apps and windows in one place.

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For details on the other small tweaks, patches, fixes and features check out the CHANGELOG diff and the commit messages below.

Merging is currently pending:

• vulkano-rs/vulkano#1145 / #233
• vulkano-rs/vulkano#1117 or better fix.
• #241.
• Wait for next release of MoltenVK with patch.

[JoshuaBatty]

Epic work dude!

[freesig]

Awesome stuff!!
I might suggest waiting for the next release of the lunarg SDK because otherwise we might have to distribute a build of MoltenVK for this to actually work. Looks like they usually release monthly and we are already over due for one. Hopefully there's a release while we are waiting for the moltenvk_deps to merge.