Initial import: LibreForts (M0-M5 in progress)

Open-source Forts clone: custom C++20 engine + data-driven (Lua) 2D physics
artillery RTS.

- Building: node/strut graph on a stiff mass-spring solver (canon Forts model),
  triangulation rigidity, axial + 30-degree angle-stress breaking, cascading
  collapse, fire (DoT + spread), ground destroys debris.
- Weapons (M4): cannon (ballistic) + laser (beam/ignite) with select-and-aim-in-
  arc UX; splash / beam damage; bg-brace passthrough.
- Devices + economy (M5): reactors + win/loss + restart, mines/turbines/battery,
  metal deposits, storage caps, per-shot energy cost.
- Data-driven via Lua/sol2 with a layered mod loader; enemy-fort scenario mod.
- Renderer: SDL3 + textures + ImGui dev UI. stb_image + ImGui vendored.
- Assets: CC0 placeholders only; real game art loaded at runtime from the user's
  own install via forts: paths (bring-your-own; nothing copyrighted committed).

See README.md / CLAUDE.md and research/ + requirements/ for detail.

1 files changed, 5 insertions, 0 deletions

diff --git a/data/structures.lua b/data/structures.lua
new file mode 100644
index 0000000..f7d88f2
--- /dev/null
+++ b/data/structures.lua
@@ -0,0 +1,5 @@
+-- Base scenario structures. Empty by default; mods under data/mods/ append to
+-- the global `Structures` list. Each structure is:
+--   { name = "...", beams = { {x1,y1,x2,y2,material}, ... } }
+-- The loader creates/merges nodes at the endpoints and welds the beams.
+Structures = Structures or {}