Refactor script logic

assets/entities/cube.lua

@@ -1,21 +1,25 @@
-local Cube = {}
+local Cube = setmetatable({}, { __index = Entity })
 Cube.__index = Cube
 
 function Cube.new()
-  local self = setmetatable({}, Cube)
+  local self = Entity.new()
-  self.id = entityAdd()
+  setmetatable(self, Cube)
-  local pos = entityPositionAdd(self.id)
+  self:add(Entity.POSITION)
-  pos.x = 0
+  self.position.x = 0
-  pos.y = 0
+  self.position.y = 0
-  pos.z = 0
+  self.position.z = 0
-  entityMeshAdd(self.id)
+  self:add(Entity.MESH)
-  local mat = entityMaterialAdd(self.id)
+  self:add(Entity.MATERIAL)
-  mat.color = colorWhite()
+  self.material.color = colorRed()
   return self
 end
 
-function Cube:dispose()
+function Cube:update()
-  entityRemove(self.id)
+  local speed = 3.0
+  local dx = inputAxis(INPUT_ACTION_LEFT, INPUT_ACTION_RIGHT)
+  local dz = inputAxis(INPUT_ACTION_UP, INPUT_ACTION_DOWN)
+  self.position.x = self.position.x + dx * speed * TIME.delta
+  self.position.z = self.position.z + dz * speed * TIME.delta
 end
 
 return Cube

assets/scenes/cube.lua

@@ -1,26 +1,30 @@
 local Cube = include('entities/cube.lua')
 
+local SceneCube = {}
+SceneCube.__index = SceneCube
+
 local cam
 local cube
 
-function Scene:init()
+function SceneCube:init()
-  print("Scene init")
+  cam = Entity.new()
-  local camId = entityAdd()
+  cam:add(Entity.POSITION)
-  local pos = entityPositionAdd(camId)
+  cam.position.x = 3
-  pos.x = 3
+  cam.position.y = 3
-  pos.y = 3
+  cam.position.z = 3
-  pos.z = 3
+  cam.position:lookAt(0, 0, 0)
-  pos:lookAt(0, 0, 0)
+  cam:add(Entity.CAMERA)
-  entityCameraAdd(camId)
-  cam = camId
 
   cube = Cube.new()
 end
 
-function Scene:update()
+function SceneCube:update()
+  cube:update()
 end
 
-function Scene:dispose()
+function SceneCube:dispose()
+  cam:dispose()
   cube:dispose()
-  entityRemove(cam)
 end
+
+return SceneCube

src/dusk/scene/scene.c

@@ -21,19 +21,23 @@
 
 scene_t SCENE;
 
-// Rebuilds the Scene global to a clean table with only Scene.set bound.
+// Releases the current scene class ref and rebuilds Scene.set global.
 static void sceneReset(void) {
   lua_State *L = SCRIPT_MANAGER.mainContext.luaState;
+  if(SCENE.scriptRef != LUA_NOREF) {
+    luaL_unref(L, LUA_REGISTRYINDEX, SCENE.scriptRef);
+    SCENE.scriptRef = LUA_NOREF;
+  }
   lua_newtable(L);
   lua_pushcfunction(L, sceneSetLua);
   lua_setfield(L, -2, "set");
   lua_setglobal(L, "Scene");
 }
 
-// Calls Scene:method() if it exists. Returns an error if the call fails.
+// Calls sceneClass:method() if it exists. Returns an error if the call fails.
 static errorret_t sceneCall(const char_t *method) {
   lua_State *L = SCRIPT_MANAGER.mainContext.luaState;
-  lua_getglobal(L, "Scene");
+  lua_rawgeti(L, LUA_REGISTRYINDEX, SCENE.scriptRef);
   lua_getfield(L, -1, method);
   if(!lua_isfunction(L, -1)) {
     lua_pop(L, 2);
@@ -45,12 +49,13 @@ static errorret_t sceneCall(const char_t *method) {
     lua_pop(L, 2);
     errorThrow("Scene:%s failed: %s", method, err);
   }
-  lua_pop(L, 1); // pop Scene
+  lua_pop(L, 1); // pop scene class
   errorOk();
 }
 
 errorret_t sceneInit(void) {
   memoryZero(&SCENE, sizeof(scene_t));
+  SCENE.scriptRef = LUA_NOREF;
   sceneReset();
   errorOk();
 }
@@ -210,8 +215,13 @@ errorret_t sceneSetImmediate(const char_t *scene) {
 
     errorChain(scriptContextExecFile(&SCRIPT_MANAGER.mainContext, scene));
 
-    // Discard any return values — we access Scene via the global.
+    int32_t nReturns = lua_gettop(L) - stackBase;
-    lua_settop(L, stackBase);
+    if(nReturns < 1 || !lua_istable(L, stackBase + 1)) {
+      lua_settop(L, stackBase);
+      errorThrow("Scene '%s' must return a table", scene);
+    }
+    lua_settop(L, stackBase + 1);
+    SCENE.scriptRef = luaL_ref(L, LUA_REGISTRYINDEX);
 
     errorChain(sceneCall("init"));
     SCENE.scriptActive = true;

src/dusk/scene/scene.h

@@ -14,6 +14,7 @@
 
 typedef struct {
   bool_t scriptActive;
+  int scriptRef;
   char_t sceneCurrent[ASSET_FILE_PATH_MAX];
   char_t sceneNext[ASSET_FILE_PATH_MAX];
 } scene_t;

src/dusk/script/module/entity/moduleentity.h

@@ -239,6 +239,54 @@ static int _entityMaterialAdd(lua_State *L) {
   return 1;
 }
 
+// ============================================================================
+// Component type Lua constants (auto-generated from componentlist.h)
+// ============================================================================
+
+#define X(enumName, type, field, init, dispose) \
+  "COMPONENT_TYPE_" #enumName " = \"" #field "\"\n"
+static const char_t *COMPONENT_TYPE_SCRIPT =
+#include "entity/componentlist.h"
+;
+#undef X
+
+// ============================================================================
+// Entity base class Lua script
+// ============================================================================
+
+static const char_t *ENTITY_SCRIPT =
+  "Entity = {}\n"
+  "Entity.__index = Entity\n"
+  "\n"
+  "Entity.POSITION = COMPONENT_TYPE_POSITION\n"
+  "Entity.CAMERA   = COMPONENT_TYPE_CAMERA\n"
+  "Entity.MESH     = COMPONENT_TYPE_MESH\n"
+  "Entity.MATERIAL = COMPONENT_TYPE_MATERIAL\n"
+  "Entity.PHYSICS  = COMPONENT_TYPE_PHYSICS\n"
+  "\n"
+  "local _addFns = {\n"
+  "  [COMPONENT_TYPE_POSITION] = entityPositionAdd,\n"
+  "  [COMPONENT_TYPE_CAMERA]   = entityCameraAdd,\n"
+  "  [COMPONENT_TYPE_MESH]     = entityMeshAdd,\n"
+  "  [COMPONENT_TYPE_MATERIAL] = entityMaterialAdd,\n"
+  "}\n"
+  "\n"
+  "function Entity.new()\n"
+  "  return setmetatable({ id = entityAdd() }, Entity)\n"
+  "end\n"
+  "\n"
+  "function Entity:add(componentType)\n"
+  "  local fn = _addFns[componentType]\n"
+  "  if not fn then error('unknown component type: ' .. tostring(componentType)) end\n"
+  "  self[componentType] = fn(self.id)\n"
+  "  return self[componentType]\n"
+  "end\n"
+  "\n"
+  "function Entity:dispose()\n"
+  "  entityRemove(self.id)\n"
+  "end\n"
+;
+
 // ============================================================================
 // entityAdd / entityRemove
 // ============================================================================
@@ -288,4 +336,7 @@ static void moduleEntity(lua_State *L) {
   lua_register(L, "entityCameraAdd",    _entityCameraAdd);
   lua_register(L, "entityMeshAdd",      _entityMeshAdd);
   lua_register(L, "entityMaterialAdd",  _entityMaterialAdd);
+
+  luaL_dostring(L, COMPONENT_TYPE_SCRIPT);
+  luaL_dostring(L, ENTITY_SCRIPT);
 }