This section is going to be a brief digression from particle systems because I would like to take the time to create a particle system design tool, which will require that we add files to the WebAssembly virtual file system. We are going to add an input element with a type of file that we can use to load an image into the virtual file system. We will need to check the file we are loading to verify it is a .png file, and if it is, we will draw and move the image around on the canvas using WebAssembly and SDL.
Emscripten does not create a virtual file system by default. Because we will need to use a virtual file system that will not initially have anything inside of it, we will need to pass the following flag to em++ to force Emscripten to build a virtual filesystem: -s FORCE_FILESYSTEM=1.
The first thing we will do is copy canvas_shell.html from...