d8b1e4dae7
2 Commits
| Author | SHA1 | Message | Date | |
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Kevin Lubick
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1f8c31b101 |
[infra] Add initial Bazel rules and files
These rules can be used to build our GMs on WASM+WebGL and libskia.a with just the CPU backend (and most other features turned off). This can be done with the following commands: - bazel build //modules/canvaskit:gm-bindings-wasm --gpu_backend=gl_backend --with_gl_standard=webgl_standard - bazel build :skia-core --config clang This pivots slightly from http://review.skia.org/463517 by using config_settings [1] instead of platforms for the optional features that we control. This pivot was suggested in [2] We have BUILD.bazel files in many of the subdirectories that specify filegroups for the appropriate files. In an effort to make //BUILD.bazel more readable, it is the responsibility of these subfolders to deal with conditionally including certain .h or .cpp files. This is done using select statements and config_settings or platform constraints as necessary. For example, src/gpu/BUILD.bazel will different private filegroups for each of the supported gpu backends [3] and a more-visible filegroup called "srcs" that has the right selection of the private files to be used for compilation. An effort has been made to avoid using glob() in our BUILD.bazel files. These file lists were made by using `ls -1` and some regex to add in quotes. We might want to make a helper script to assist with that, if necessary. To specify which options we have, the settings in //bazel/common_config_settings/BUILD.bazel have been redesigned. They make use of a macro `string_flag_with_values` that removes the boilerplate. Patchset 36 shows what the file looks like w/o the macro. The top level BUILD.bazel file will still need to use some logic to handle defines, because local_defines is a list of strings, not a list of labels [4]. Suggested Review Order: - WORKSPACE.bazel to see the new dependencies on the emsdk toolchain and bazel_skylib - bazel/common_config_settings/* to see the few settings defined (we have more to define, see BUILD.gn and //gn/skia.gni for ideas) - BUILD.bazel to see the "skia-core" cc_library rule. See also "gms" and "tests" - modules/canvaskit/BUILD.bazel to see the use of the emscripten "wasm_cc_binary" rule, which depends on the "skia-core", "gms", and "tests" rule. Note that it only builds some of the gms as a proof of concept. - The other BUILD.bazel files. Some of these are not platform or feature dependent (e.g. pathops). Others are (e.g. gpu). - All other files. [1] https://docs.bazel.build/versions/4.2.1/skylark/config.html#user-defined-build-settings [2] https://github.com/emscripten-core/emsdk/pull/920 [3] In this CL, that's just the webgl one. [4] https://docs.bazel.build/versions/main/be/c-cpp.html#cc_library.local_defines Change-Id: Ieecf9c106d5e3a6ae97d13d66be06b4b3c207089 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/458637 Reviewed-by: Ben Wagner <bungeman@google.com> Reviewed-by: Leandro Lovisolo <lovisolo@google.com> Owners-Override: Kevin Lubick <kjlubick@google.com> |
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Kevin Lubick
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262dfbafb4 |
[experimental] Add WebGPU demo (built with Bazel)
This uses the Bazel rule wasm_cc_binary, which is defined in @emsdk [1] Note that wasm_cc_binary does not have a linkopts argument defined, so we instead put any emcc options in the cc_binary target. This works around a few bugs in the emsdk Bazel rules: - https://github.com/emscripten-core/emsdk/issues/907 - https://github.com/emscripten-core/emsdk/issues/807 Prior to PS 5, this CL tried a different way to bring in the toolchain, a more manual way outlined in [2]. A similar approach (modifying the .bazelrc and specifying the toolchain directly) might be necessary at some point, but can probably still be done using the @emsdk Bazel rules and --config=wasm. To update the version of emscripten used, we just need to update the parameter in the WORKSPACE call to emsdk_emscripten_deps(). The example/index.html file in this CL does exactly the same as [3], except the WebGPU calls are made from C++ via WASM. I made heavy use of these examples [4], [5] while exploring APIs. What was also useful was looking at the emscripten source headers [6], [7], [8], [9]. I also learned a lot about WebGPU from [10]. [1] |