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.

3 files changed, 26 insertions, 0 deletions

diff --git a/data/mods/enemy-fort/map.lua b/data/mods/enemy-fort/map.lua
new file mode 100644
index 0000000..443b74b
--- /dev/null
+++ b/data/mods/enemy-fort/map.lua
@@ -0,0 +1,3 @@
+-- The enemy fort's reactor (team 1). Sits inside the fort (columns x=25..29).
+-- Destroy it to win.
+table.insert(MapDevices, { type = "reactor", x = 27, y = 3.0, team = 1 })
diff --git a/data/mods/enemy-fort/mod.lua b/data/mods/enemy-fort/mod.lua
new file mode 100644
index 0000000..b2bc990
--- /dev/null
+++ b/data/mods/enemy-fort/mod.lua
@@ -0,0 +1,4 @@
+-- Scenario mod: a prebuilt enemy fort on the right for the player to shoot at.
+Selectable = true
+Priority   = 5
+Category   = "Scenario"
diff --git a/data/mods/enemy-fort/structures.lua b/data/mods/enemy-fort/structures.lua
new file mode 100644
index 0000000..ce6bdd0
--- /dev/null
+++ b/data/mods/enemy-fort/structures.lua
@@ -0,0 +1,19 @@
+-- A triangulated wooden fort on the right side (columns at x=25,27,29; rows at
+-- y=1,3,5). Foundations sit on the ground (y=1). All beams <= 3 units so they
+-- obey the material length limits. Shoot it apart with the cannon.
+table.insert(Structures, {
+    name = "enemy fort",
+    beams = {
+        -- verticals
+        {25,1,25,3,"wood"}, {25,3,25,5,"wood"},
+        {27,1,27,3,"wood"}, {27,3,27,5,"wood"},
+        {29,1,29,3,"wood"}, {29,3,29,5,"wood"},
+        -- horizontals
+        {25,1,27,1,"wood"}, {27,1,29,1,"wood"},
+        {25,3,27,3,"wood"}, {27,3,29,3,"wood"},
+        {25,5,27,5,"wood"}, {27,5,29,5,"wood"},
+        -- diagonals (triangulation, so it's rigid)
+        {25,1,27,3,"wood"}, {27,1,29,3,"wood"},
+        {25,3,27,5,"wood"}, {27,3,29,5,"wood"},
+    },
+})