Add optimize_wasm build option for Web
#105388
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adamscott
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| @@ -57,6 +58,11 @@ def get_opts(): | |||
| "Use Emscripten PROXY_TO_PTHREAD option to run the main application code to a separate thread", | |||
| False, | |||
| ), | |||
| BoolVariable( | |||
| "optimize_wasm", | |||
| "Use binaryen `wasm-opt` to reduce the output .wasm file sizes", | |||
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| "Use binaryen `wasm-opt` to reduce the output .wasm file sizes", | |
| "Use Binaryen `wasm-opt` to reduce the output WebAsssembly file sizes (requires `wasm-opt` in `PATH`)", |
| def run_optimize_wasm(target, source, env): | ||
| wasmopt_bin_path = WhereIs("wasm-opt") | ||
| if wasmopt_bin_path is None: | ||
| raise UserError('[wasm-opt] Cannot find `wasm-opt`. That binary usually comes with the "binaryen" package.') |
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| raise UserError('[wasm-opt] Cannot find `wasm-opt`. That binary usually comes with the "binaryen" package.') | |
| raise UserError('[wasm-opt] Cannot find `wasm-opt` in `PATH`. That binary usually comes with the "binaryen" package.') |
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Tested locally (rebased on top of master 6a6a116), it mostly works as expected.
One issue is that the new file does not replace the existing WASM file in bin/. Instead, it creates a new file with the name godot.web.template_release.wasm32.opt.wasm (notice .opt which is normally not here). It should replace the existing WASM file so that you don't need to change anything else to your packaging process.
Also, Emscripten's copy of wasm-opt (which is in emsdk/upstream/bin/wasm-opt) is already automatically called when you compile a web export template. Is there a way to use more aggressive arguments out of the box when using optimize=speed|size|size_extra, so we don't need to run it twice? Reusing Emscripten's copy of wasm-opt would also remove the need for the user to supply their own copy of wasm-opt. See also #97457 (comment).
Benchmark
Web release export template:
| Type | Uncompressed | gzip -9 |
brotli --best |
zstd --ultra -22 |
|---|---|---|---|---|
wasm_opt=no |
37,477,863 bytes | 9,116,302 bytes | 6,228,636 bytes | 6,677,737 bytes |
wasm_opt=yes |
34,207,409 bytes | 8,909,506 bytes | 6,231,975 bytes | 6,684,047 bytes |
Note
This PR is the second of two (maybe more to come?) that intends to apply some optimizations underlined by @popcar2 in his great blog post on How to Minify Godot's Build Size (93MB -> 6.4MB exe).
Warning
Heads-up release management team: This is an independent PR from #105371, but I would prefer the latter being merged first as there will be conflicts.
This PR adds the
optimize_wasmbuild option for the Web platform. This will permit people to optimize the built wasm files from the Godot build script, without having to manually do it. It requires though thewasm-optcommand line utility from the binaryen project.Hopefully, this will enable smaller engine downloads for players on the Web.