How to run SDL3 with OpenGL ES 2.0 on WebAssembly

You should go through this guide first: How to run SDL3 app on Web with WebAssembly

This guide should be completed the next: Convert rendering using the SDL3 API to rendering using OpenGL ES 2.0

Now you can rebuild the project. Open CMD in the 'sdl3-sample\build\web' and type this command: mingw32-make