I wanted a bare-bones program for SDL2 + OpenGL 2D rendering that also compiled to JS+WebGL with Emscripten+Wasm. There are some SDL2 + OpenGL tutorials out there but most of them don’t target the WebGL subset of OpenGL. I can’t use the fixed function pipeline, so older OpenGL code won’t work, and I can’t use newer things like vertex array objects, instancing, or geometry shaders, so newer OpenGL code often won’t work. [Note: as of 2026, the WebGL 1 vertex array object extension has 100% support, and instancing is near 100%. And both are fully supported in WebGL 2.]

Installation

The Makefile should work on Linux and MacOS. The code should work on Windows and other SDL+OpenGL platforms but may need minor modifications; I haven’t tested them.

Install SDL2

On Mac using Homebrew:

brew install SDL2 SDL2_image

On RedHat/Fedora flavors of Linux:

sudo yum install SDL2-devel SDL2_image-devel

On Debian/Ubuntu flavors of Linux:

sudo apt install libsdl2-dev libsdl2-image-dev

On Arch flavors of Linux:

sudo pacman -S sdl2 sdl2_image

Install STB, Dear Imgui

git submodule init
git submodule update

Compiling and running

To run the native code:

make local && bin/main

To run the emscripten code: (brew install emscripten on Mac, pacman -S emscripten on Arch Linux):

make emscripten

and then tell the webserver to serve the files from www/.

My Emscripten-ed wasm output is on my web site.

I’ve also written a partial CMakeLists.txt file but am not using it yet.

The font included in this project is Droid Sans, under the Apache License v2. The ImGui library includes the Proggy font.