While working out how to use the stencil buffer in Garry's Mod I had to read a lot of tutorials and then mangle a whole bunch of code to get a proper idea on what things were actually doing.
This repository is an attempt to distill all that knowledge into a series of documented runnable examples that I hope will help people, and enrich the sadly unfilled Garry's Mod Wiki.
The examples will make great use of the entity sent_stencil_test which is
just a prop that doesn't draw itself by default. You could easily substitute
it for any other entity of your own.
It is under the category "Dev Stuff" in the Sandbox spawn menu. If you spawn
one but lose it, run stencil_tutorial_draw_ents 1 in console and it will
start rendering. Run stencil_tutorial_draw_ents 0 to hide it again.
When running an example, use lua_openscript_cl, for example
] lua_openscript_cl stencil_tutorial/basic_clipping.lua
Each example will override the previous, so you can just run them
sequentially. To end an example, run the console command
stencil_tutorial_end_example.