Struct GpuClassInput 

pub struct GpuClassInput {
    pub vendor: GpuVendor,
    pub memory_budget_bytes: u64,
    pub discrete: bool,
    pub apple_family: u8,
}

The cheap signals every backend can gather about its GPU, mapped to a coarse GpuTier by one shared rule so the three backends classify consistently and the mapping is unit-testable without a GPU. The backends differ in what they can report (Apple exposes a GPU family; DirectX / Vulkan expose a VRAM figure and a discrete / integrated flag), so this carries the union and the rule uses whichever signals are present.

Fields

vendor: GpuVendor

The GPU’s vendor.

memory_budget_bytes: u64

Device memory the driver reports as budgeted for this process.

discrete: bool

Whether the GPU is a discrete card.

apple_family: u8

Apple GPU family generation rank (7 = M1 .. 10 = M4), or 0 for a non-Apple GPU. Apple silicon classifies by generation; everything else by VRAM.