[kolkov]

Summary

The WebGPU software backend (GOGPU_GRAPHICS_API=software, the automatic fallback when no GPU is usable, and the path the GPU tests take in CI) built its device by hand from github.com/gogpu/wgpu/hal/software through hal.InstanceDescriptor and wgpu.NewDeviceFromHAL. Two problems came out of that:

• hal/ and core/ are wgpu's implementation, and they are moving under internal/, so this code would stop compiling on a future wgpu update.
• Against current wgpu, the hand-built device no longer passed the compute availability probe. Under GOGPU_GRAPHICS_API=software, every GPU test skipped without a sound.

The software adapter now comes through the public API, the way Rust wgpu does it:

instance, _ := wgpu.CreateInstance(nil) // every registered backend, software included
adapter, _ := instance.RequestAdapter(&wgpu.RequestAdapterOptions{ForceFallbackAdapter: true})
device, _ := adapter.RequestDevice(nil)

Changes

• internal/backend/webgpu/backend.go: newSoftwareBackend now uses CreateInstance, ForceFallbackAdapter and RequestDevice. The wgpu/hal and wgpu/hal/software imports are gone. Only the blank hal/allbackends import that registers the backends is left. The adapter info comes from the adapter instead of a hard-coded struct.
• The deprecated wgpu.Backends* aliases are replaced with gputypes.Backends*.
• New software_backend_test.go checks two things:
  • GOGPU_GRAPHICS_API=software yields a CPU adapter;
  • no non-test file in the backend imports wgpu/hal/... or wgpu/core/.... This check fails on the old code.
• With the software tests running again, TestLazyModeAdd's 100 ms bound no longer holds there: the SPIR-V interpreter runs the dispatch inside Add. The bound is skipped on CPU adapters.
• .gitignore: ignore a local project-management directory.
• CHANGELOG entry under Unreleased.

Test plan

• go build ./..., go vet
• GOGPU_GRAPHICS_API=software go test ./internal/backend/webgpu/ -count=1
• Same with vulkan and dx12 on a real GPU
• golangci-lint run
• CI green

[codecov]

Codecov Report

❌ Patch coverage is 31.81818% with 15 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/backend/webgpu/backend.go	31.81%	14 Missing and 1 partial ⚠️

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