Add Lua support for partial sim updates

src/lua/LuaScriptInterface.cpp

@@ -939,6 +939,8 @@ void LuaScriptInterface::initSimulationAPI()
 		{"listCustomGol", simulation_listCustomGol},
 		{"addCustomGol", simulation_addCustomGol},
 		{"removeCustomGol", simulation_removeCustomGol},
+		{"lastUpdatedID", simulation_lastUpdatedID},
+		{"updateUpTo", simulation_updateUpTo},
 		{NULL, NULL}
 	};
 	luaL_register(l, "simulation", simulationAPIMethods);
@@ -2477,6 +2479,53 @@ int LuaScriptInterface::simulation_removeCustomGol(lua_State *l)
 	return 1;
 }
 
+int LuaScriptInterface::simulation_lastUpdatedID(lua_State *l)
+{
+	if (luacon_sim->debug_mostRecentlyUpdated != -1)
+	{
+		lua_pushinteger(l, luacon_sim->debug_mostRecentlyUpdated);
+	}
+	else
+	{
+		lua_pushnil(l);
+	}
+	return 1;
+}
+
+int LuaScriptInterface::simulation_updateUpTo(lua_State *l)
+{
+	int upTo = NPART - 1;
+	if (lua_gettop(l) > 0)
+	{
+		upTo = luaL_checkinteger(l, 1);
+	}
+	if (upTo < 0 || upTo >= NPART)
+	{
+		return luaL_error(l, "ID not in valid range");
+	}
+	if (upTo < luacon_sim->debug_currentParticle)
+	{
+		upTo = NPART - 1;
+	}
+	if (luacon_sim->debug_currentParticle == 0)
+	{
+		luacon_sim->framerender = 1;
+		luacon_sim->BeforeSim();
+		luacon_sim->framerender = 0;
+	}
+	luacon_sim->UpdateParticles(luacon_sim->debug_currentParticle, upTo);
+	if (upTo < NPART - 1)
+	{
+		luacon_sim->debug_currentParticle = upTo + 1;
+	}
+	else
+	{
+		luacon_sim->AfterSim();
+		luacon_sim->debug_currentParticle = 0;
+	}
+	return 0;
+}
+
 //// Begin Renderer API
 
 void LuaScriptInterface::initRendererAPI()

src/lua/LuaScriptInterface.h

@@ -119,6 +119,8 @@ class LuaScriptInterface: public CommandInterface
 	static int simulation_listCustomGol(lua_State *l);
 	static int simulation_addCustomGol(lua_State *l);
 	static int simulation_removeCustomGol(lua_State *l);
+	static int simulation_lastUpdatedID(lua_State *l);
+	static int simulation_updateUpTo(lua_State *l);
 
 
 	//Renderer

src/simulation/Simulation.cpp

@@ -3484,6 +3484,7 @@ void Simulation::UpdateParticles(int start, int end)
 	for (i = start; i <= end && i <= parts_lastActiveIndex; i++)
 		if (parts[i].type)
 		{
+			debug_mostRecentlyUpdated = i;
 			t = parts[i].type;
 
 			x = (int)(parts[i].x+0.5f);
@@ -5183,6 +5184,8 @@ void Simulation::BeforeSim()
 
 void Simulation::AfterSim()
 {
+	debug_mostRecentlyUpdated = -1;
+
 	if (emp_trigger_count)
 	{
 		// pitiful attempt at trying to keep code relating to a given element in the same file

src/simulation/Simulation.h

@@ -55,6 +55,7 @@ public:
 
 	char can_move[PT_NUM][PT_NUM];
 	int debug_currentParticle;
+	int debug_mostRecentlyUpdated = -1; // -1 when between full update loops
 	int parts_lastActiveIndex;
 	int pfree;
 	int NUM_PARTS;