Game as the Core mod: data-driven content and localization

The whole game is now described by Mods/Core — the first consumer of
the engine's new MrGameEng.Mods module:

- textures/ moved to Mods/Core/Textures; atlases are built at game
  start from the merged texture tree of all active mods into Cache/
  (gitignored, incremental) instead of being committed, and the
  GameAssets atlas handles are gone with them
- terrain, plants and pawns are JSON defs (Mods/Core/Defs) with parent
  inheritance; scenes read TerrainDef/PlantDef/PawnDef instead of
  hardcoded arrays, and the TerrainKind enum is retired
- HUD strings come from Mods/Core/Languages (ru default, en fallback)
  through LanguageManager; the language switches at runtime
- new console commands: mods, lang [code], defs [type]; atlas now
  inspects the runtime-built cache
- bump engine: MrGameEng.Mods module and the explicit-sources
  AtlasBuilder overload

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -414,3 +414,7 @@ FodyWeavers.xsd
 # Built Visual Studio Code Extensions
 *.vsix
 
+
+# LittleSim
+Cache/
+

CLAUDE.md

@@ -16,7 +16,9 @@ Game design docs live in `docs/` and are written in **Russian**. Engine rules li
 ```
 engine/        mrgameeng git submodule (own repo, own CLAUDE.md)
 src/LittleSim  the game (net8.0); references engine projects directly
-docs/          концепт, симуляция, roadmap (Russian)
+Mods/Core      the game's own content as a mod: About, Defs, Languages, Textures
+Cache/         runtime-built atlases (gitignored)
+docs/          концепт, симуляция, моды, roadmap (Russian)
 LittleSim.sln  game + engine sources + engine tests — one window for everything
 ```
 
@@ -29,18 +31,19 @@ dotnet run --project src/LittleSim -c Release   # measure perf in Release only
 dotnet test LittleSim.sln                        # runs the engine test suites
 ```
 
-## Texture atlases
+## Content and mods
 
-Source images live in `textures/` (committed); the game only loads packed atlases from
-`src/LittleSim/Assets/Atlases` (also committed — the asset generator emits
-`GameAssets.Atlases.*` handles for them). After changing `textures/`, rebuild with:
+All game content is data in mods (`MrGameEng.Mods`): the game itself ships as the
+`Core` mod. `Mods/Core/Defs` holds JSON defs (terrain, plants, pawns — see
+`docs/mods.md`), `Mods/Core/Languages/{ru,en}` holds UI strings (default language is
+`ru`), `Mods/Core/Textures` holds source images. New mechanics get defs + localization
+keys, not hardcoded arrays; UI strings go through `LanguageManager`, never inline.
 
-```
-dotnet run --project engine/tools/MrGameEng.AtlasTool -c Release -- textures src/LittleSim/Assets/Atlases --group-depth 2
-```
-
-Rebuilds are incremental (unchanged groups are skipped). Region keys are paths relative
-to `textures/` without extension: `atlas.GetRegion("things/plant/treeoak/TreeOakA")`.
+Atlases are built **at game start** from the merged texture tree of all active mods
+into `Cache/Atlases` (incremental: unchanged groups are skipped, a clean first run
+takes ~20 s). Region keys are paths relative to `Textures/` without extension:
+`atlases.GetRegion(device, "things/plant/treeoak/TreeOakA")`. Console commands:
+`mods`, `lang [code]`, `defs [type]`, `atlas [name]`.
 
 ## Submodule workflow
 
@@ -57,4 +60,6 @@ Never commit a pointer to an unpushed engine commit.
 - Simulation/presentation split: simulation systems mutate components only;
   rendering reads them. No draw calls or UI from simulation systems.
 - ECS-first per the engine: plain `struct : IComponent` data, logic in systems.
+- Content as data: numbers, textures and balance live in `Mods/Core/Defs`, user-facing
+  strings in `Mods/Core/Languages` — code only defines systems and def classes.
 - Every new mechanic gets a dev-console command for testing (`regen`, `timescale`, …).

LittleSim.sln

@@ -47,6 +47,10 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MrGameEng.Pathfinding.Tests
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MrGameEng.Collisions.Tests", "engine\tests\MrGameEng.Collisions.Tests\MrGameEng.Collisions.Tests.csproj", "{B9161776-32FE-415E-9401-DC5BB87FC225}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MrGameEng.Mods", "engine\src\MrGameEng.Mods\MrGameEng.Mods.csproj", "{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MrGameEng.Mods.Tests", "engine\tests\MrGameEng.Mods.Tests\MrGameEng.Mods.Tests.csproj", "{07986629-FE7C-42BE-868B-0FCA1915D2A2}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -273,6 +277,30 @@ Global
 		{B9161776-32FE-415E-9401-DC5BB87FC225}.Release|x64.Build.0 = Release|Any CPU
 		{B9161776-32FE-415E-9401-DC5BB87FC225}.Release|x86.ActiveCfg = Release|Any CPU
 		{B9161776-32FE-415E-9401-DC5BB87FC225}.Release|x86.Build.0 = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|x64.Build.0 = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Debug|x86.Build.0 = Debug|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|x64.ActiveCfg = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|x64.Build.0 = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|x86.ActiveCfg = Release|Any CPU
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82}.Release|x86.Build.0 = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|x64.Build.0 = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Debug|x86.Build.0 = Debug|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|x64.ActiveCfg = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|x64.Build.0 = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|x86.ActiveCfg = Release|Any CPU
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -298,5 +326,7 @@ Global
 		{9406DB4C-FABF-48FE-BEA7-25AD319D2172} = {F4A69A46-AF86-AB4E-7D23-4CCCB7B9A519}
 		{47E5E756-64F9-4B5A-8EC3-B016745166C4} = {CD3B5CE5-C23F-38B4-04AA-A303F94731A5}
 		{B9161776-32FE-415E-9401-DC5BB87FC225} = {CD3B5CE5-C23F-38B4-04AA-A303F94731A5}
+		{F91AA8C8-FD6B-4B92-BB3A-844DCA932D82} = {F4A69A46-AF86-AB4E-7D23-4CCCB7B9A519}
+		{07986629-FE7C-42BE-868B-0FCA1915D2A2} = {CD3B5CE5-C23F-38B4-04AA-A303F94731A5}
 	EndGlobalSection
 EndGlobal

Mods/Core/About/About.json

@@ -0,0 +1,8 @@
+{
+  "id": "Core",
+  "name": "LittleSim Core",
+  "author": "mrleo1nid",
+  "version": "0.1.0",
+  "description": "Базовый контент LittleSim: рельеф, растения, существа, текстуры и локализация. Игра целиком описана как мод — любой другой мод может переопределить её содержимое.",
+  "dependencies": []
+}

Mods/Core/Defs/pawns.json

@@ -0,0 +1,22 @@
+{
+  "type": "Pawn",
+  "defs": [
+    { "defName": "BaseBeing", "abstract": true, "kind": "being", "sizeCells": 1.1 },
+    { "defName": "BeingMale",   "parent": "BaseBeing", "label": "pawn.being", "texture": "things/pawn/humanlike/bodies/FurCovered_Male_south" },
+    { "defName": "BeingFemale", "parent": "BaseBeing", "label": "pawn.being", "texture": "things/pawn/humanlike/bodies/FurCovered_Female_south" },
+    { "defName": "BeingThin",   "parent": "BaseBeing", "label": "pawn.being", "texture": "things/pawn/humanlike/bodies/FurCovered_Thin_south" },
+    { "defName": "BeingFat",    "parent": "BaseBeing", "label": "pawn.being", "texture": "things/pawn/humanlike/bodies/FurCovered_Fat_south" },
+    { "defName": "BeingHulk",   "parent": "BaseBeing", "label": "pawn.being", "texture": "things/pawn/humanlike/bodies/FurCovered_Hulk_south" },
+
+    { "defName": "BaseAnimal", "abstract": true, "kind": "animal" },
+    { "defName": "Bear",     "parent": "BaseAnimal", "label": "pawn.bear",     "texture": "things/pawn/animal/bear/Bear_east",             "sizeCells": 1.7 },
+    { "defName": "DeerDoe",  "parent": "BaseAnimal", "label": "pawn.deer",     "texture": "things/pawn/animal/deer/DeerFemale_east",       "sizeCells": 1.4 },
+    { "defName": "DeerBuck", "parent": "BaseAnimal", "label": "pawn.deer",     "texture": "things/pawn/animal/deer/DeerMale_east",         "sizeCells": 1.6 },
+    { "defName": "FoxRed",   "parent": "BaseAnimal", "label": "pawn.fox",      "texture": "things/pawn/animal/fox_red/Fox_Red_east",       "sizeCells": 1.0 },
+    { "defName": "Hare",     "parent": "BaseAnimal", "label": "pawn.hare",     "texture": "things/pawn/animal/hare/Hare_east",             "sizeCells": 0.7 },
+    { "defName": "WildBoar", "parent": "BaseAnimal", "label": "pawn.boar",     "texture": "things/pawn/animal/wildboar/WildBoar_east",     "sizeCells": 1.2 },
+    { "defName": "Wolf",     "parent": "BaseAnimal", "label": "pawn.wolf",     "texture": "things/pawn/animal/wolf_timber/Wolf_Timber_east", "sizeCells": 1.4 },
+    { "defName": "Muffalo",  "parent": "BaseAnimal", "label": "pawn.muffalo",  "texture": "things/pawn/animal/muffalo/Muffalo_east",       "sizeCells": 1.8 },
+    { "defName": "Squirrel", "parent": "BaseAnimal", "label": "pawn.squirrel", "texture": "things/pawn/animal/squirrel/Squirrel_east",     "sizeCells": 0.6 }
+  ]
+}

Mods/Core/Defs/plants.json

@@ -0,0 +1,17 @@
+{
+  "type": "Plant",
+  "defs": [
+    { "defName": "BaseTree", "abstract": true, "sizeCells": 2.0, "trunkRadiusCells": 0.28 },
+    { "defName": "TreeOakA",      "parent": "BaseTree", "label": "plant.oak",   "texture": "things/plant/treeoak/TreeOakA" },
+    { "defName": "TreeOakB",      "parent": "BaseTree", "label": "plant.oak",   "texture": "things/plant/treeoak/TreeOakB" },
+    { "defName": "TreeBirchA",    "parent": "BaseTree", "label": "plant.birch", "texture": "things/plant/treebirch/TreeBirchA" },
+    { "defName": "TreeGrayPineA", "parent": "BaseTree", "label": "plant.pine",  "texture": "things/plant/treegraypine/TreeGrayPineA" },
+
+    { "defName": "GrassA", "label": "plant.grass", "texture": "things/plant/grass/grassa", "sizeCells": 1.2 },
+
+    { "defName": "BaseBush", "abstract": true, "label": "plant.bush", "sizeCells": 1.4 },
+    { "defName": "BushA", "parent": "BaseBush", "texture": "things/plant/bush/BushA" },
+    { "defName": "BushB", "parent": "BaseBush", "texture": "things/plant/bush/BushB" },
+    { "defName": "BushC", "parent": "BaseBush", "texture": "things/plant/bush/BushC" }
+  ]
+}

Mods/Core/Defs/terrain.json

@@ -0,0 +1,22 @@
+{
+  "type": "Terrain",
+  "defs": [
+    { "defName": "DeepWater", "label": "terrain.deepwater", "maxHeight": 0.30, "color": [23, 63, 95] },
+    { "defName": "Water",     "label": "terrain.water",     "maxHeight": 0.42, "color": [32, 99, 155] },
+    { "defName": "Sand",      "label": "terrain.sand",      "maxHeight": 0.48, "color": [237, 201, 120],
+      "isLand": true, "surface": "terrain/surfaces/sand" },
+    { "defName": "Grass",     "label": "terrain.grass",     "maxHeight": 0.68, "color": [90, 160, 70],
+      "isLand": true, "surface": "terrain/surfaces/mossy",
+      "scatter": [
+        { "chance": 0.35, "options": ["GrassA"] },
+        { "chance": 0.07, "options": ["BushA", "BushB", "BushC"] }
+      ] },
+    { "defName": "Forest",    "label": "terrain.forest",    "maxHeight": 0.85, "color": [44, 110, 50],
+      "isLand": true, "surface": "terrain/surfaces/soil",
+      "scatter": [
+        { "chance": 0.35, "options": ["TreeOakA", "TreeOakB", "TreeBirchA", "TreeGrayPineA"] }
+      ] },
+    { "defName": "Mountain",  "label": "terrain.mountain",  "maxHeight": 1.01, "color": [136, 132, 128],
+      "surface": "terrain/surfaces/roughhewnrock" }
+  ]
+}

Mods/Core/Languages/en/ui.json

@@ -0,0 +1,28 @@
+{
+  "hud.world": "LittleSim | seed {0} | population {1} | {2} FPS",
+  "hud.terrain": "LittleSim | terrain | seed {0} | animals: {1}",
+  "hud.controls": "WASD — camera, wheel — zoom, ` — console ('help' lists commands)",
+
+  "terrain.deepwater": "deep water",
+  "terrain.water": "water",
+  "terrain.sand": "sand",
+  "terrain.grass": "grass",
+  "terrain.forest": "forest",
+  "terrain.mountain": "mountains",
+
+  "plant.oak": "oak",
+  "plant.birch": "birch",
+  "plant.pine": "pine",
+  "plant.grass": "grass tuft",
+  "plant.bush": "bush",
+
+  "pawn.being": "being",
+  "pawn.bear": "bear",
+  "pawn.deer": "deer",
+  "pawn.fox": "fox",
+  "pawn.hare": "hare",
+  "pawn.boar": "boar",
+  "pawn.wolf": "wolf",
+  "pawn.muffalo": "muffalo",
+  "pawn.squirrel": "squirrel"
+}

Mods/Core/Languages/ru/ui.json

@@ -0,0 +1,28 @@
+{
+  "hud.world": "LittleSim | сид {0} | население {1} | {2} FPS",
+  "hud.terrain": "LittleSim | террейн | сид {0} | животных: {1}",
+  "hud.controls": "WASD — камера, колесо — зум, ` — консоль ('help' — список команд)",
+
+  "terrain.deepwater": "глубокая вода",
+  "terrain.water": "вода",
+  "terrain.sand": "песок",
+  "terrain.grass": "трава",
+  "terrain.forest": "лес",
+  "terrain.mountain": "горы",
+
+  "plant.oak": "дуб",
+  "plant.birch": "берёза",
+  "plant.pine": "сосна",
+  "plant.grass": "пучок травы",
+  "plant.bush": "куст",
+
+  "pawn.being": "житель",
+  "pawn.bear": "медведь",
+  "pawn.deer": "олень",
+  "pawn.fox": "лиса",
+  "pawn.hare": "заяц",
+  "pawn.boar": "кабан",
+  "pawn.wolf": "волк",
+  "pawn.muffalo": "муффало",
+  "pawn.squirrel": "белка"
+}