emscripten setup

Have you ever made a project in openFrameworks and been like "This is awesome! I want to put it on my online portfolio!". You could always make a video or take photos, but what about the UI aspect of your project? How can people see the awesome mouse effects you made? Enter Emscripten. Emscripten translates your C++ code into Javascript code in a matter of minutes! So you can put your awesome OF project "on the line" in your portfolio.

These instruction will show you how to compile one example project in the openFrameworks distribution, and can be reused whenever you want to translate an openFrameworks sketch to a web page. Assuming that you have downloaded openFrameworks 0.9 (it works only with OF versions >= 0.9) you only have to install emscripten and compile a project with it. Here the instruction steb by step.

Install Emscripten

The recommended way to install Emscripten is to install directly from the Emscripten repo with git. Open a terminal at the location where you want the emsdk to be installed and run the followings commands:

git clone https://github.com/emscripten-core/emsdk
cd emsdk
./emsdk install latest-fastcomp
./emsdk activate latest-fastcomp
source ./emsdk_env.sh

If the above doesn't work for any reason. You can try using the incoming SDK which might not be as stable:

git clone https://github.com/emscripten-core/emsdk
cd emsdk
./emsdk install sdk-incoming-64bit
./emsdk activate sdk-incoming-64bit
source ./emsdk_env.sh

For 32bit systems swap the -64bit for -32bit.

Note: Because the current emsdk script uses Python2, you may get errors if the default python command on your machine is aliased to Python3. In this case, try explicitly running the above commands with Python2. For example: python2 ./emsdk update.

The installation will take a while. When it is finished, type source ./emsdk_env.sh to set the system path to the active version of Emscripten. You can copy the output of this command and add it to your .profile file, in order to save this variables also for the next sessions.

Note: If you have a previous install of emscripten you will want to delete the compiled code in your OF_FOLDER. Delete any files or obj folders inside of OF_FOLDER/libs/openFrameworksCompiled/lib/emscripten/ and any obj/ folders in your project folders before trying to compile.

Compile an openFrameworks project using emscripten

Open the terminal in in one project in the examples folder, like examples/3d/3DPrimitivesExample, and compile the project using this command

emmake make

Once the compilation is finished, there will be a new file in examples/3d/3DPrimitivesExample/bin, the 3DPrimitivesExample.html file. Open this file with the command:

emrun bin/3DPrimitivesExample.html

If it does not work, it is probably because you are opening with safari, and safari does not support WebGL. Let's open it with another browser, like chrome

emrun --browser chrome bin/3DPrimitivesExample.html

If everything works, you should see this image

This Tutorial is taken from this blog post by Regine Flores Mir.