MTLResource

MTLResource is a protocol in Apple’s Metal framework that defines the common interface for GPU resources. It is adopted by concrete resource types such as MTLBuffer and MTLTexture, which represent memory regions used for data storage and texture data on the GPU. The protocol provides a uniform set of capabilities that all resource objects share, regardless of their specific kind or storage location.

Key aspects of MTLResource include a reference to the device that created the resource, an optional label for debugging and profiling, and metadata describing how the resource is stored and accessed. Resources expose information about memory configuration, including cache behavior for CPU access (cpuCacheMode) and the memory location and behavior (storageMode). Some implementations also expose a hazard-tracking mode, reflecting how the runtime tracks potential hazards when resources are used across CPU and GPU.

A notable feature of MTLResource is support for purgeable state management. The protocol defines a method to set the resource’s purgeable state, allowing the system to reclaim memory when necessary. Applications can query and adjust the purgeability of resources to balance performance and memory pressure.

Usage and lifetimes: Resources are created by the device, often via specific creation methods that return objects conforming to MTLResource (for example, buffers and textures). They may be allocated directly or from a heap (MTLHeap). The exact capabilities and available properties depend on the concrete resource type and the platform version.

Notes: API availability and behavior can vary by OS version and device. MTLResource serves as the foundational interface; details are implemented by MTLBuffer, MTLTexture, and related resource classes.