Add lua script class

3 years ago · 8a740f55ba
3 changed files with 283 additions and 0 deletions
--- a/assets/lua/cameracontroller.lua
+++ b/assets/lua/cameracontroller.lua
@ -0,0 +1,32 @@
+LuaScript = {
+
+	camera = nil,
+
+	initialize = function(self)
+		--
+	end,
+
+	destroy = function(self)
+		--
+	end,
+
+	update = function(self, deltaTime)
+		self.camera = GetComponent("CameraComponent")
+		LuaScript:updateOrthographic(deltaTime)
+		LuaScript:updatePerspective(deltaTime)
+
+		local tmp = self.camera.fov
+		self.camera.fov = 30.0
+
+		--
+	end,
+
+	updateOrthographic = function(self, deltaTime)
+		--
+	end,
+
+	updatePerspective = function(self, deltaTime)
+		--
+	end,
+
+}
--- a/inferno/src/inferno/script/lua.cpp
+++ b/inferno/src/inferno/script/lua.cpp
@ -0,0 +1,205 @@
+extern "C" {
+	#include <lua/lua.h>
+	#include <lua/lualib.h>
+	#include <lua/lauxlib.h>
+}
+
+#include "inferno/assertions.h"
+#include "inferno/file.h"
+#include "inferno/scene/components.h"
+#include "inferno/scene/scene.h"
+#include "inferno/script/lua.h"
+
+namespace Inferno {
+
+	void Lua::initialize()
+	{
+		m_state = luaL_newstate();
+
+		// Add GetComponent()
+		// ---------------------------------
+
+		constexpr int32_t componentUpValueAmount = 1;
+		lua_pushlightuserdata(m_state, this);
+		lua_pushcclosure(m_state, Lua::getComponent, componentUpValueAmount);
+		lua_setglobal(m_state, "GetComponent");
+
+		// Add Metatable
+		// ---------------------------------
+
+		luaL_newmetatable(m_state, "ComponentMetatable");
+
+		constexpr int32_t indexUpValueAmount = 1;
+		lua_pushstring(m_state, "__index");
+		lua_pushlightuserdata(m_state, this);
+		lua_pushcclosure(m_state, Lua::componentIndex, indexUpValueAmount);
+		lua_settable(m_state, -3); // Pops the string and table
+
+		constexpr int32_t newIndexUpValueAmount = 1;
+		lua_pushstring(m_state, "__newindex");
+		lua_pushlightuserdata(m_state, this);
+		lua_pushcclosure(m_state, Lua::componentNewIndex, newIndexUpValueAmount);
+		lua_settable(m_state, -3); // Pops the string and table
+
+		// Load and Initialize Script
+		// ---------------------------------
+
+		loadScript();
+
+		getFunction("LuaScript", "initialize");
+		callFunction();
+	}
+
+	void Lua::destroy()
+	{
+		getFunction("LuaScript", "destroy");
+		callFunction();
+
+		lua_close(m_state);
+		m_state = nullptr;
+	}
+
+	void Lua::update(float deltaTime)
+	{
+		getFunction("LuaScript", "update");
+		lua_pushnumber(m_state, deltaTime); // Push float argument
+		callFunction(1);
+	}
+
+	void Lua::valid(int32_t error)
+	{
+		ASSERT(error == LUA_OK, "{}", lua_tostring(m_state, -1));
+	}
+
+	void Lua::loadScript()
+	{
+		std::string script = File::read(m_path);
+		int32_t error = luaL_dostring(m_state, script.c_str());
+		valid(error);
+	}
+
+	void Lua::getFunction(const char* table, const char* function)
+	{
+		Lua::isTable(m_state, table);           // Push table
+		int32_t tableIdx = lua_gettop(m_state); // Get table stack index
+		lua_pushstring(m_state, function);      // Push string
+		lua_gettable(m_state, -2);              // Pop string key, push value
+		lua_pushvalue(m_state, tableIdx);       // Push table
+	}
+
+	void Lua::callFunction(int32_t parameters)
+	{
+		int32_t error = lua_pcall(m_state, parameters + 1, 0, 0); // Call function()
+		valid(error);
+	}
+
+	void Lua::isTable(lua_State* state, int32_t table)
+	{
+		ASSERT(lua_istable(state, table));
+	}
+
+	void Lua::isTable(lua_State* state, const char* table)
+	{
+		lua_getglobal(state, table); // Push table on the stack
+		Lua::isTable(state, -1);
+	}
+
+	int32_t Lua::getComponent(lua_State* state) // Local scope state, so stack begins at 1!
+	{
+		ASSERT(lua_gettop(state) == 1, "Lua called with wrong amount of arguments");
+
+		ASSERT(lua_islightuserdata(state, lua_upvalueindex(1)), "Lua did not receive required lightuserdata");
+		Lua* self = static_cast<Lua*>(lua_touserdata(state, lua_upvalueindex(1)));
+
+		// Verify parameter
+		std::string componentName = lua_tostring(state, -1);
+		ASSERT(lua_isstring(state, -1), "Lua did not receive correct parameter");
+
+		// Create userdata
+		/*void* pointer =*/ lua_newuserdatauv(state, sizeof(0), 2); // Push userdata
+		ASSERT(lua_isuserdata(state, -1), "Lua could not create userdata");
+
+		// Get component
+		void* component = nullptr;
+		if (componentName.compare("CameraComponent") == 0) {
+			component = static_cast<void*>(&self->m_scene->getComponent<CameraComponent>(self->m_entity));
+		}
+
+		// Add metatable to userdata
+		luaL_getmetatable(state, "ComponentMetatable"); // Push table
+		ASSERT(lua_istable(state, -1), "Lua could not find metatable");
+		lua_setmetatable(state, -2); // Pop table, set it as metatable onto userdata
+
+		// Add uservalues to userdata
+		lua_pushstring(state, componentName.c_str()); // Push string
+		lua_setiuservalue(state, -2, 1);              // Pop value, set it as the n-th uservalue onto userdata
+		lua_pushlightuserdata(state, component);      // Push pointer
+		lua_setiuservalue(state, -2, 2);              // Pop value, set it as the n-th uservalue onto userdata
+
+		return 1; // Return amount of stack items pushed
+	}
+
+	int32_t Lua::componentIndex(lua_State* state) // Local scope state, so stack begins at 1!
+	{
+		ASSERT(lua_gettop(state) == 2, "Lua called with wrong amount of arguments");
+		ASSERT(lua_isuserdata(state, -2)); // 1 // <component>.x
+		ASSERT(lua_isstring(state, -1));   // 2 // component.<x>
+
+		// ASSERT(lua_islightuserdata(state, lua_upvalueindex(1)), "Lua did not receive required lightuserdata");
+		// Lua* self = static_cast<Lua*>(lua_touserdata(state, lua_upvalueindex(1)));
+
+		lua_getiuservalue(state, 1, 1); // Push the n-th uservalue from userdata
+		ASSERT(lua_isstring(state, -1), "Lua did not receive component type correctly");
+		std::string componentName = lua_tostring(state, -1);
+
+		if (componentName.compare("CameraComponent") == 0) {
+
+			lua_getiuservalue(state, 1, 2); // Push the n-th uservalue from userdata
+			ASSERT(lua_islightuserdata(state, -1), "Lua did not receive component pointer correctly");
+			CameraComponent* component = (CameraComponent*)lua_touserdata(state, -1);
+
+			std::string index = lua_tostring(state, 2);
+			if (index.compare("fov") == 0) {
+				lua_pushnumber(state, component->fov);
+				return 1;
+			}
+			else {
+				ASSERT_NOT_REACHED();
+			}
+
+		}
+
+		return 0;
+	}
+
+	int32_t Lua::componentNewIndex(lua_State* state) // Local scope state, so stack begins at 1!
+	{
+		ASSERT(lua_gettop(state) == 3, "Lua called with wrong amount of arguments");
+		ASSERT(lua_isuserdata(state, -3)); // 1 // <component>.x = thing
+		ASSERT(lua_isstring(state, -2));   // 2 // component.<x> = thing
+		// Value we want to set -1         // 3 // component.x   = <thing>
+
+		lua_getiuservalue(state, 1, 1); // Push the n-th uservalue from userdata
+		ASSERT(lua_isstring(state, -1), "Lua did not receive component type correctly");
+		std::string componentName = lua_tostring(state, -1);
+
+		if (componentName.compare("CameraComponent") == 0) {
+
+			lua_getiuservalue(state, 1, 2); // Push the n-th uservalue from userdata
+			ASSERT(lua_islightuserdata(state, -1), "Lua did not receive component pointer correctly");
+			CameraComponent* component = (CameraComponent*)lua_touserdata(state, -1);
+
+			std::string index = lua_tostring(state, 2);
+			if (index.compare("fov") == 0) {
+				component->fov = lua_tonumber(state, 3);
+			}
+			else {
+				ASSERT_NOT_REACHED();
+			}
+
+		}
+
+		return 0;
+	}
+
+}
--- a/inferno/src/inferno/script/lua.h
+++ b/inferno/src/inferno/script/lua.h
@ -0,0 +1,46 @@
+#ifndef LUA_H
+#define LUA_H
+
+#include <cstdint> // int32_t, uint32_t
+#include <string>  // std::string
+
+#include <lua/lua.h> // lua_State
+
+namespace Inferno {
+
+	struct TransformComponent;
+
+	class Scene;
+
+	class Lua {
+	public:
+		void initialize();
+		void destroy();
+		void update(float deltaTime);
+
+		void valid(int32_t error);
+		void loadScript();
+		void getFunction(const char* table, const char* function);
+		void callFunction(int32_t parameters = 0);
+
+	private:
+		static void isTable(lua_State* state, int32_t table);
+		static void isTable(lua_State* state, const char* table);
+
+		static int32_t getComponent(lua_State* state);
+		static int32_t componentIndex(lua_State* state);
+		static int32_t componentNewIndex(lua_State* state);
+
+		std::string m_path = "";
+		lua_State* m_state = nullptr;
+
+		Scene* m_scene = nullptr;
+		uint32_t m_entity = 0;
+		TransformComponent* transform = nullptr;
+
+		friend class ScriptSystem;
+	};
+
+}
+
+#endif // LUA_H