a-simple-triangle / Part 13 - Vulkan introduction

Ok strap yourself in - now we start the journey of implementing our Vulkan rendering system. We will get Vulkan running on all of our target platforms that support it - which is pretty much everything except for Emscripten.

Before we get into the technical swing of things I would strongly recommend learning about Vulkan itself. This is the official site for the Vulkan APIs: https://www.khronos.org/vulkan/.

I had a lot of trouble understanding Vulkan and my fluency with it is still pretty basic. The way I was able to learn about it was from these awesome sites:

• Official Khronos resources site: https://github.com/KhronosGroup/Khronosdotorg/blob/master/api/vulkan/resources.md
• Vulkan Tutorial: https://vulkan-tutorial.com/
• C++ Examples and demos: https://github.com/SaschaWillems/Vulkan
• Vulkan - API without secrets: https://software.intel.com/en-us/articles/api-without-secrets-introduction-to-vulkan-preface

By working my way through some of the Vulkan tutorial sites and cross referencing demos in the Github links above, I was able to get Vulkan up and running successfully on my Mac and other platforms. One of the key outcomes I pushed for was to use the Vulkan C++ header instead of the C header, to allow for - in my opinion - a more pleasing coding style and architecture.

The things that I’ll be doing differently to a lot of the online articles I learned from:

• Along with Android and Windows, I’ll be showing how to get Vulkan running on MacOS and iOS with our shared code base - I found desperately little about how to get Vulkan running successfully on Apple systems via MoltenVK which is needed to interface with Apple’s Metal renderer as Apple actually doesn’t directly support Vulkan at all.
• I’ll be using the C++ Vulkan header interface instead of the default C interface, so we can write our Vulkan code similarly to our existing code taking advantage of components such as our internal_ptr for auto cleanup of resources.
• I’ll be showing how to use Vulkan via SDL2 which is what our code base foundation sits on - most of the Vulkan documentation and articles I found assumed the developer was running on Windows using GLFW which as I mentioned at the start of this series is not a valid approach to support mobile platforms and MacOS.

We will be using Vulkan 1.0 because we want to support back to Android 7 Nougat (API-24) which was the first version of Android to ship with Vulkan 1.0 support and additionally the MoltenVK library only maps to Vulkan 1.0 (at least at the time of writing these articles that was the case), so we want to be as backward compatible as we can.

Our Emscripten platform won’t be able to use Vulkan as it is limited to WebGL, though in the future it might be possible using libraries such as ANGLE.

As we did with the OpenGL based articles, we’ll begin by writing as much automated setup scripts to bootstrap the target platforms to use Vulkan, followed by the actual usage of the Vulkan SDK itself.

We have already written quite a lot of the core foundation for our engine so the good news is that we won’t take as long to get to the rendering code this time - though brace yourself there is far more rendering code for Vulkan!

Before continuing

Running Vulkan applications has a few extra constraints compared to OpenGL:

• To develop or run Vulkan/MoltenVK for the Mac console or MacOS targets you’ll need to be on a Mac of 2012 vintage or later - thankfully my own Mac just scrapes in (2012 Macbook Air).
• To run an iOS application using Vulkan (via MoltenVK) or an Android Vulkan application you will have to run on a real physical device. At the time of writing it didn’t seem possible to run Vulkan on the iOS simulator. Also for Android although you can deploy a Vulkan enabled application to the Android emulator it won’t be able to actually create the required Vulkan components to run properly. For iOS we will also need to drop support for devices older than the iPhone 5s as they don’t have Metal support which is needed for MoltenVK integration.
• Windows users - I guess it should work so long as your graphics hardware and drivers are Vulkan capable.

Continue to Part 14: Vulkan setup console.

End of part 13

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