The client can do a test run of their application with
a persistent cache set to SkSL mode. They store the key
and data blobs that are produced.
Ship those blobs with the application. At startup, call
GrContext::precompileShader for each key/data pair. This
compiles the shaders, and stores the GL program ID, plus
a small amount of metadata in our runtime program cache.
Caveats:
* Currently only implemented for the GL backend. Other
backends will require more metadata to do any useful
amount of work. Metal may need a more drastic workflow
change, involving offline compilation of the shaders.
* Currently only implemented for cached SkSL (not GLSL
or program binaries). Supporting other formats again
requires more metadata, and the cached shaders become
increasingly specialized to GPU and driver versions.
* Reusing the cached SkSL on different hardware is not
supported. Many driver workarounds are implemented in
the SkSL -> GLSL transformation, but some are higher
level. Limiting device variance by artificially hiding
extensions may help, but there are no guarantees.
* The 'gltestprecompile' DM config exercises this code
similarly to 'gltestpersistentcache', ensuring that
results are visually identical when precompiling, and
that no cache misses occur after precompiling.
Change-Id: Id314c5d5f5a58fe503a0505a613bd4a540cc3589
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/239438
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
ed58e004e0