With Apple’s recent unfortunate decision to deprecate
OpenGL support in iOS and Mac OS moving forward this will be the end to the only graphics API that worked natively across all platforms. I think many developers would be willing to ignore the Mac OS market, but the iOS market is just too big for most people to ignore. What then are the alternatives to using OpenGL? In this article we are going to look at exactly that topic. Use a game engine and let them worry about it!
This is the category probably the majority of developers are going to fall under. If you use an engine like Unity or Unreal this entire thing becomes a non-issue. These engines generally already support a number of different rendering options, including native Metal support. For other small or open source engines such as Godot, CopperCube, Shiva, Cocos, etc this is a bigger problem as they now potentially have to dedicate more time, money and/or resources to support yet another renderer… or drop support for Apple platforms completely. Unless they rely on some kind of abstraction layer for rendering, life just got a bit more annoying for every single game engine manufacturer that previously supported Apple platforms.
The following engines have Metal support out of the box:
Unreal Engine Unity Lumberyard Armory(via Kha) Stingray (now defunct) Use Vulkan + MoltenVK
A lot of game developers and engine developers specifically were planning to, or already have, implemented
Vulkan rendering support. Vulkan is a lower level alternative to OpenGL, from Khronos Group, the same people behind OpenGL. Like Direct3D 12 and even Apple’s Metal, Vulkan is designed in a closer to the hardware manner, to better maximize new graphical functionality in modern GPUs. Working in Vulkan takes a lot more effort than working in OpenGL or similar higher level APIs, but it is cross platform much the same way as OpenGL was. The catch… it doesn’t work on Apple products. Ugh. Ok, how then is this a solution? We there is a product called MoltenVK that enables Vulkan to run on Apple’s Metal. Use an Abstraction Layer
Another option I’m really partial too… letting someone else do all the work! There are a handful of low level cross platform graphics APIs that take care of the work for you. So if you don’t want to use an existing game engine, but also don’t want to deal with rendering intricacies for each platform, this could be a great option. Well will discuss available cross platform layers.
A cross platform “bring your own engine/framework” graphics rendering layer with bindings for several programming languages an renderers, including Metal ( and OpenGL, Direct3D, WebGL and more). No Vulkan support however, at least not yet.
Kore is the open source C framework that kha is built on top of. Kore supports a ton of renderers including metal. You can learn more about kha
in this video.
Ogre straddles the line between game engine and framework. Either way, ogre3d has a metal renderer for iOS and MacOS.
This one is fairly new to me, it’s a cross platform rendering framework that also supports Metal.
Veldrid is a .NET based rendering and computer library that supports Metal (as well as VUlkan, D3D11 and OpenGL, GL ES). I have no personal experience with this library and it seems somewhat young from a developmental perspective.
There are mutiple mentions and forks of SDL for supporting Metal. I’m not sure if any are complete or still supported.
Implement A Metal Renderer
Of course you’ve always got the option of buckling down and implementing a Metal renderer for MacOS and iOS platforms. Of course your work will only be useful on Mac/iOS platforms. If you are interested in learning more about Metal you can learn more
here. Stick with OpenGL
Of course you’ve always got the option of just sticking with OpenGL. Deprecated doesn’t mean it wont run on existing devices, just future ones. Publish your game as it is now and let Apple deal with the fallout of their bad business decisions.