VVMetalKit

VVMetalKit is a framework that contains a couple basic Metal-based utilities I use for the various projects I work on. The pool for recycling textures and buffers is the main feature offered by this framework- most of the other classes are intended to simplify workflows around rendering to, populating, converting, or displaying textures.

Essentials:

• RenderProperties is a global singleton for conveniently storing/retrieving values you'll use frequently. This is the first thing you'll want to configure if you're using this framework.
• VVMTLPool is a texture and buffer pool- recycling textures and buffers is significantly faster than trashing and re-creating them every time you need one. If you're working with Metal textures/buffers, this is probably the second thing you'll want to create.
• VVMTLTextureImage-protocol is a protocol/class that describes a poolable image in a Metal texture. Instances of this class always come from VVMTLPool. The texture may or may not be backed by either a CPU-based resource or a GPU-based resource, depending on how the texture/image was created by the pool.
• VVMTLBuffer-protocol is a protocol/class that describes a poolable buffer accessible to Metal. Instances of this class always come from VVMTLPool. The buffer may or may not be backed by shared memory, depending on how it was created by the pool.
• VVMTLTextureImageView is a high-level NSView subclass that uses Metal to display a VVMTLTextureImage-protocol as large as possible without cropping. Under the hood, it uses CustomMetalView, which is an NSView that uses Metal to draw its contents- kind of like MTKView, which makes it more configurable...

Other useful classes:

• VVMTLScene is a superclass that contains a number of properties and methods used to "render content to a texture". You probably won't work with it directly, but will instead want to subclass one of its subclasses:
• VVMTLComputeScene is a subclass of VVMTLScene that is used to perform compute-based rendering operations (id<MTLComputeCommandEncoder>). This class is intended to be subclassed- CopierMTLScene is one such example.
• VVMTLOrthoRenderScene is a subclass of VVMTLRenderScene that is used to perform orthographic render-to-texture operations using id<MTLRenderCommandEncoder>. This class is intended to be subclassed- CMVMTLDrawObjectScene is one such example.
• VVMTLPerspRenderScene is a subclass of VVMTLRenderScene similar that performs non-orthographic render-to-texture operations using id<MTLRenderCommandEncoder>. This class is also intended to be subclassed.
• CIMTLScene is a subclass of VVMTLScene and a convenient way to render CIImage instances to texture/images.
• CopierMTLScene is a subclass of VVMTLComputeScene and a convenient way to copy a texture by running it through a compute shader, while optionally resizing the image using different sizing modes (fit/fill/copy).
• CMVMTLDrawObject is intended to simplify the process of drawing 2D shapes to textures- it encodes draw commands to geometry buffers which can be executed in arbitrary render contexts. CMVMTLDrawObjectScene is a companion object- a subclass of VVMTLScene that allows you to render one or more draw objects to a texture. CMVMTLDrawObjectView is another companion object that renders a draw object directly to a Metal view (it doesn't render to a texture).
• VVMTLTextureLUT-protocol is a protocol/class for a poolable, texture-backed LUT you can fetch from VVMTLPool.
• VVMTLTimestamp is a class that is used to timestamp objects vended by VVMTLPool.
• VVMTLUtilities.h contains a number of handy functions, particularly for boucing CGImageRefs to VVMTLTextureImages and vice versa.
• AAPLMathUtilties.h is provided by Apple, and contains a bunch of handy general-purpose math functions suited for using matrices to manipulate geometry.
• CIImageAdditions.h is a CIImage class addition that adds a strong ref to CIImage instances that retains a VVMTLTextureImage-protocol for the lifetime of the CIImage.
• SwizzleMTLScene is a class that uses Metal compute to do pixel format conversion on the GPU.

Documentation:

Documentation is provided in Apple's "DocC" format- it's also documented heavily with traditional inline comments.

Licensing

This is all BSD licensed, you can do whatever you want with it and feel good about yourself! If you have any ideas for improvements (or you find any bugs or problems), please open an issue and let me know.