implement PyBullet removeState command. Fixes Issue #2163

https://github.com/bulletphysics/bullet3/issues/2163

examples/SharedMemory/PhysicsClientC_API.cpp

@@ -108,6 +108,25 @@ B3_SHARED_API b3SharedMemoryCommandHandle b3LoadStateCommandInit(b3PhysicsClient
 	return 0;
 }
 
+B3_SHARED_API b3SharedMemoryCommandHandle b3InitRemoveStateCommand(b3PhysicsClientHandle physClient, int stateId)
+{
+	PhysicsClient* cl = (PhysicsClient*)physClient;
+	b3Assert(cl);
+	b3Assert(cl->canSubmitCommand());
+
+	if (cl->canSubmitCommand())
+	{
+		struct SharedMemoryCommand* command = cl->getAvailableSharedMemoryCommand();
+		b3Assert(command);
+		command->m_type = CMD_REMOVE_STATE;
+		command->m_updateFlags = 0;
+		command->m_loadStateArguments.m_fileName[0] = 0;
+		command->m_loadStateArguments.m_stateId = stateId;
+		return (b3SharedMemoryCommandHandle)command;
+	}
+	return 0;
+}
+
 B3_SHARED_API int b3LoadStateSetStateId(b3SharedMemoryCommandHandle commandHandle, int stateId)
 {
 	struct SharedMemoryCommand* command = (struct SharedMemoryCommand*)commandHandle;

examples/SharedMemory/PhysicsClientC_API.h

@@ -375,6 +375,7 @@ extern "C"
 	B3_SHARED_API int b3LoadUrdfCommandSetGlobalScaling(b3SharedMemoryCommandHandle commandHandle, double globalScaling);
 
 	B3_SHARED_API b3SharedMemoryCommandHandle b3SaveStateCommandInit(b3PhysicsClientHandle physClient);
+	B3_SHARED_API b3SharedMemoryCommandHandle b3InitRemoveStateCommand(b3PhysicsClientHandle physClient, int stateId);
 	B3_SHARED_API int b3GetStatusGetStateId(b3SharedMemoryStatusHandle statusHandle);
 
 	B3_SHARED_API b3SharedMemoryCommandHandle b3LoadStateCommandInit(b3PhysicsClientHandle physClient);

examples/SharedMemory/PhysicsClientSharedMemory.cpp

@@ -1429,6 +1429,8 @@ const SharedMemoryStatus* PhysicsClientSharedMemory::processServerStatus()
 			case CMD_SYNC_USER_DATA_COMPLETED:
 			case CMD_REMOVE_USER_DATA_COMPLETED:
 			case CMD_ADD_USER_DATA_COMPLETED:
+			case CMD_REMOVE_STATE_FAILED:
+			case CMD_REMOVE_STATE_COMPLETED:
 			{
 				break;
 			}

examples/SharedMemory/PhysicsDirect.cpp

@@ -1159,6 +1159,14 @@ void PhysicsDirect::postProcessStatus(const struct SharedMemoryStatus& serverCmd
 			}
 			break;
 		}
+		case CMD_REMOVE_STATE_FAILED:
+		{
+			break;
+		}
+		case CMD_REMOVE_STATE_COMPLETED:
+		{
+			break;
+		}
 		default:
 		{
 			//b3Warning("Unknown server status type");

examples/SharedMemory/PhysicsServerCommandProcessor.cpp

@@ -10777,7 +10777,7 @@ bool PhysicsServerCommandProcessor::processLoadTextureCommand(const struct Share
 
 bool PhysicsServerCommandProcessor::processSaveStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes)
 {
-	BT_PROFILE("CMD_RESTORE_STATE");
+	BT_PROFILE("CMD_SAVE_STATE");
 	bool hasStatus = true;
 	SharedMemoryStatus& serverCmd = serverStatusOut;
 	serverCmd.m_type = CMD_SAVE_STATE_FAILED;
@@ -10791,15 +10791,57 @@ bool PhysicsServerCommandProcessor::processSaveStateCommand(const struct SharedM
 	if (bulletFile->ok())
 	{
 		serverCmd.m_type = CMD_SAVE_STATE_COMPLETED;
-		serverCmd.m_saveStateResultArgs.m_stateId = m_data->m_savedStates.size();
+		//re-use state if available
+		int reuseStateId = -1;
+		for (int i = 0; i < m_data->m_savedStates.size(); i++)
+		{
+			if (m_data->m_savedStates[i].m_bulletFile == 0)
+			{
+				reuseStateId = i;
+				break;
+			}
+		}
 		SaveStateData sd;
 		sd.m_bulletFile = bulletFile;
 		sd.m_serializer = ser;
+		if (reuseStateId >= 0)
+		{
+			serverCmd.m_saveStateResultArgs.m_stateId = reuseStateId;
+			m_data->m_savedStates[reuseStateId] = sd;
+		}
+		else
+		{
+			serverCmd.m_saveStateResultArgs.m_stateId = m_data->m_savedStates.size();
 			m_data->m_savedStates.push_back(sd);
 		}
+	}
 	return hasStatus;
 }
 
+
+bool PhysicsServerCommandProcessor::processRemoveStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes)
+{
+	BT_PROFILE("CMD_REMOVE_STATE");
+	bool hasStatus = true;
+	SharedMemoryStatus& serverCmd = serverStatusOut;
+	serverCmd.m_type = CMD_REMOVE_STATE_FAILED;
+	
+	if (clientCmd.m_loadStateArguments.m_stateId >= 0)
+	{
+		if (clientCmd.m_loadStateArguments.m_stateId < m_data->m_savedStates.size())
+		{
+			SaveStateData& sd = m_data->m_savedStates[clientCmd.m_loadStateArguments.m_stateId];
+			delete sd.m_bulletFile;
+			delete sd.m_serializer;
+			sd.m_bulletFile = 0;
+			sd.m_serializer = 0;
+			serverCmd.m_type = CMD_REMOVE_STATE_COMPLETED;
+		}
+	}
+	return hasStatus;
+}
+
+
 bool PhysicsServerCommandProcessor::processRestoreStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes)
 {
 	BT_PROFILE("CMD_RESTORE_STATE");
@@ -10817,9 +10859,12 @@ bool PhysicsServerCommandProcessor::processRestoreStateCommand(const struct Shar
 		if (clientCmd.m_loadStateArguments.m_stateId < m_data->m_savedStates.size())
 		{
 			bParse::btBulletFile* bulletFile = m_data->m_savedStates[clientCmd.m_loadStateArguments.m_stateId].m_bulletFile;
+			if (bulletFile)
+			{
 				ok = importer->convertAllObjects(bulletFile);
 			}
 		}
+	}
 	else
 	{
 		bool found = false;
@@ -11328,6 +11373,11 @@ bool PhysicsServerCommandProcessor::processCommand(const struct SharedMemoryComm
 			hasStatus = processSaveStateCommand(clientCmd, serverStatusOut, bufferServerToClient, bufferSizeInBytes);
 			break;
 		}
+		case CMD_REMOVE_STATE:
+		{
+			hasStatus = processRemoveStateCommand(clientCmd, serverStatusOut, bufferServerToClient, bufferSizeInBytes);
+			break;
+		}
 
 		case CMD_LOAD_BULLET:
 		{

examples/SharedMemory/PhysicsServerCommandProcessor.h

@@ -81,6 +81,7 @@ protected:
 	bool processLoadMJCFCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
 	bool processRestoreStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
 	bool processSaveStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
+	bool processRemoveStateCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
 	bool processSyncUserDataCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
 	bool processRequestUserDataCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);
 	bool processAddUserDataCommand(const struct SharedMemoryCommand& clientCmd, struct SharedMemoryStatus& serverStatusOut, char* bufferServerToClient, int bufferSizeInBytes);

examples/SharedMemory/SharedMemoryPublic.h

@@ -7,8 +7,8 @@
 //Please don't replace an existing magic number:
 //instead, only ADD a new one at the top, comment-out previous one
 
-
+#define SHARED_MEMORY_MAGIC_NUMBER 201904030
-#define SHARED_MEMORY_MAGIC_NUMBER 201902120
+//#define SHARED_MEMORY_MAGIC_NUMBER 201902120
 //#define SHARED_MEMORY_MAGIC_NUMBER 201811260
 //#define SHARED_MEMORY_MAGIC_NUMBER 201810250
 //#define SHARED_MEMORY_MAGIC_NUMBER 201809030
@@ -93,6 +93,7 @@ enum EnumSharedMemoryClientCommand
 	CMD_REQUEST_PHYSICS_SIMULATION_PARAMETERS,
 	CMD_SAVE_STATE,
 	CMD_RESTORE_STATE,
+	CMD_REMOVE_STATE,
 	CMD_REQUEST_COLLISION_SHAPE_INFO,
 
 	CMD_SYNC_USER_DATA,
@@ -218,6 +219,8 @@ enum EnumSharedMemoryServerStatus
 	CMD_ADD_USER_DATA_FAILED,
 	CMD_REMOVE_USER_DATA_COMPLETED,
 	CMD_REMOVE_USER_DATA_FAILED,
+	CMD_REMOVE_STATE_COMPLETED,
+	CMD_REMOVE_STATE_FAILED,
 	//don't go beyond 'CMD_MAX_SERVER_COMMANDS!
 	CMD_MAX_SERVER_COMMANDS
 };

examples/pybullet/examples/saveRestoreState.py

@@ -80,6 +80,10 @@ setupWorld()
 #both restore from file or from in-memory state should work
 p.restoreState(fileName="state.bullet")
 stateId = p.saveState()
+print("stateId=",stateId)
+p.removeState(stateId)
+stateId = p.saveState()
+print("stateId=",stateId)
 
 if verbose:
 	p.setInternalSimFlags(1)

examples/pybullet/pybullet.c

@@ -1160,6 +1160,40 @@ static PyObject* pybullet_saveState(PyObject* self, PyObject* args, PyObject* ke
 	return PyInt_FromLong(stateId);
 }
 
+static PyObject* pybullet_removeState(PyObject* self, PyObject* args, PyObject* keywds)
+{
+	{
+		int stateUniqueId = -1;
+		b3PhysicsClientHandle sm = 0;
+
+		int physicsClientId = 0;
+		static char* kwlist[] = { "stateUniqueId", "physicsClientId", NULL };
+		if (!PyArg_ParseTupleAndKeywords(args, keywds, "i|i", kwlist, &stateUniqueId, &physicsClientId))
+		{
+			return NULL;
+		}
+		sm = getPhysicsClient(physicsClientId);
+		if (sm == 0)
+		{
+			PyErr_SetString(SpamError, "Not connected to physics server.");
+			return NULL;
+		}
+		if (stateUniqueId >= 0)
+		{
+			b3SharedMemoryStatusHandle statusHandle;
+			int statusType;
+			if (b3CanSubmitCommand(sm))
+			{
+				statusHandle = b3SubmitClientCommandAndWaitStatus(sm, b3InitRemoveStateCommand(sm, stateUniqueId));
+				statusType = b3GetStatusType(statusHandle);
+			}
+		}
+	}
+
+	Py_INCREF(Py_None);
+	return Py_None;
+}
+
 static PyObject* pybullet_loadMJCF(PyObject* self, PyObject* args, PyObject* keywds)
 {
 	const char* mjcfFileName = "";
@@ -10329,6 +10363,9 @@ static PyMethodDef SpamMethods[] = {
 	{"saveState", (PyCFunction)pybullet_saveState, METH_VARARGS | METH_KEYWORDS,
 	 "Save the full state of the world to memory."},
 
+	 { "removeState", (PyCFunction)pybullet_removeState, METH_VARARGS | METH_KEYWORDS,
+	"Remove a state created using saveState by its state unique id." },
+
 	{"loadMJCF", (PyCFunction)pybullet_loadMJCF, METH_VARARGS | METH_KEYWORDS,
 	 "Load multibodies from an MJCF file."},