Update README instructions for using Emscripten

- Point to a newer URL
- Use emcmake and emmake (which will set the CMake project file)

Change-Id: I3341b9f8e741436bc5961fbc77586963f3241c7a
This commit is contained in:
Zhi An Ng 2021-05-21 11:47:01 -07:00
parent 6fb4cddc93
commit 29145ed692

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@ -10,26 +10,18 @@ This file describes the compilation of libwebp into a JavaScript decoder
using Emscripten and CMake.
- install the Emscripten SDK following the procedure described at:
https://kripken.github.io/emscripten-site/docs/getting_started/downloads.html
https://emscripten.org/docs/getting_started/downloads.html#installation-instructions-using-the-emsdk-recommended
After installation, you should have some global variable positioned to the
location of the SDK. In particular, $EMSCRIPTEN should point to the
location of the SDK. In particular, $EMSDK should point to the
top-level directory containing Emscripten tools.
- make sure the file $EMSCRIPTEN/cmake/Modules/Platform/Emscripten.cmake is
accessible. This is the toolchain file used by CMake to invoke Emscripten.
If $EMSCRIPTEN is unset search for Emscripten.cmake under $EMSDK and set
$EMSCRIPTEN accordingly, for example:
unix-like environments: export EMSCRIPTEN=$EMSDK/upstream/emscripten
windows: set EMSCRIPTEN=%EMSDK%\upstream\emscripten
- configure the project 'WEBP_JS' with CMake using:
cd webp_js && \
cmake -DWEBP_BUILD_WEBP_JS=ON \
-DCMAKE_TOOLCHAIN_FILE=$EMSCRIPTEN/cmake/Modules/Platform/Emscripten.cmake \
emcmake cmake -DWEBP_BUILD_WEBP_JS=ON \
../
- compile webp.js using 'make'.
- compile webp.js using 'emmake make'.
- that's it! Upon completion, you should have the webp.js and
webp.wasm files generated.