This is a simple(-ish) example embedding Guile Scheme into a program running SDL2 & OpenGL (via glew)
Build and run the program:
./meta.scm build-and-run scripts/hello.scm- Press Ctrl + R to hot-reload Guile/OpenGL shader code
- Press Ctrl + W to enable/disable automatic hot-reload when the Guile file is modified
Passing the flag
--auto-reloadafter the script path will enable this by default
Configuration for meta can be found in config.scm
More commands for meta can be found by running:
./meta.scm helpsudo apt install libsdl2-dev libglew-dev guile-3.0 guile-3.0-devOpenGL <-> Guile glue is in glue/gl.c
SDL <-> Guile glue is in glue/sdl.c
These are brought together in glue/bind.c
Simple helper macros for this section are defined in include/glue/glueing-utils.h
main.c creates a window using SDL, sets up the OpenGL context, and then initializes Guile with the glue code builder function. It then executes the script provided as a command line argument (scripts/hello.scm is provided/explained here) with an exception handler which simply prints the exception and exits, for now
The script is allowed to perform any setup needed, and is expected to define two procedures called update and render, which are then called in a loop by main.c (again, in an exception handler) until the program is exited
During the event loop, SDL keyup is checked for Ctrl + R, in which case the model is reset and the guile code is reloaded
On initialization, hello.scm creates a vertex buffer, vao, uniforms, and simple shader program with a source loaded via Guile ports, binding these with the glue code
In update, the script gets the SDL window size with the glue code, and calculates updated values for cpu-side versions of uniforms in a simple way
In render, the script binds the program and vao, updates the OpenGL uniforms, then calls gl:draw-triangles