Book Image

Learn WebAssembly

By : Mike Rourke
Book Image

Learn WebAssembly

By: Mike Rourke

Overview of this book

WebAssembly is a brand-new technology that represents a paradigm shift in web development. This book teaches programmers to leverage this technology to write high-performance applications that run in the browser. This book introduces you to powerful WebAssembly concepts to help you write lean and powerful web applications with native performance. You start with the evolution of web programming, the state of things today, and what can be done with the advent and release of WebAssembly. We take a look at the journey from JavaScript to asm.js to WebAssembly. We then move on to analyze the anatomy of a WebAssembly module and the relationship between binary and text formats, along with the corresponding JavaScript API. Further on, you'll implement all the techniques you've learned to build a high-performance application using C and WebAssembly, and then port an existing game written in C++ to WebAssembly using Emscripten. By the end of this book, you will be well-equipped to create high-performance applications and games for the web using WebAssembly.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Dedication
PacktPub.com
Contributors
Preface
Index

Compiling C without the glue code


If we want to use WebAssembly according to the official specification, without the extra features that Emscripten provides, we need to pass some flags to the emcc command and ensure we're writing code that can be used by WebAssembly with relative ease. In the Writing the example C code section, we wrote a program that rendered a blue rectangle that moved diagonally across a red canvas. It utilized one of Emscripten's ported libraries, SDL2. In this section, we're going to write and compile some C code that doesn't rely on Emscripten's helper methods and ported libraries.

C code for WebAssembly

Before we get to the C code we'll use for our WebAssembly module, let's try an experiment. Open the CLI in the /chapter-05-create-load-module folder, and try running this command:

emcc with-glue.c -Os -s WASM=1 -s USE_SDL=2 -s SIDE_MODULE=1 -s BINARYEN_ASYNC_COMPILATION=0 -o try-with-glue.wasm

You should see a try-with-glue.wasm file appear in VS Code's file explorer panel...