blender/source/gameengine/Ketsji/KX_StateActuator.cpp
Benoit Bolsee 5372def2b0 BGE patch: add state engine support in the logic bricks.
This patch introduces a simple state engine system with the logic bricks. This system features full
backward compatibility, multiple active states, multiple state transitions, automatic disabling of 
sensor and actuators, full GUI support and selective display of sensors and actuators. 
Note: Python API is available but not documented yet. It will be added asap.

State internals
===============
The state system is object based. The current state mask is stored in the object as a 32 bit value; 
each bit set in the mask is an active state. The controllers have a state mask too but only one bit
can be set: a controller belongs to a single state. The game engine will only execute controllers 
that belong to active states. Sensors and actuators don't have a state mask but are effectively 
attached to states via their links to the controllers. Sensors and actuators can be connected to more
than one state. When a controller becomes inactive because of a state change, its links to sensors 
and actuators are temporarily broken (until the state becomes active again). If an actuator gets isolated, 
i.e all the links to controllers are broken, it is automatically disabled. If a sensor gets isolated, 
the game engine will stop calling it to save CPU. It will also reset the sensor internal state so that
it can react as if the game just started when it gets reconnected to an active controller. For example,
an Always sensor in no pulse mode that is connected to a single state (i.e connected to one or more 
controllers of a single state) will generate a pulse each time the state becomes active. This feature is 
not available on all sensors, see the notes below.

GUI
===
This system system is fully configurable through the GUI: the object state mask is visible under the
object bar in the controller's colum as an array of buttons just like the 3D view layer mask.
Click on a state bit to only display the controllers of that state. You can select more than one state
with SHIFT-click. The All button sets all the bits so that you can see all the controllers of the object. 
The Ini button sets the state mask back to the object default state. You can change the default state 
of object by first selecting the desired state mask and storing using the menu under the State button. 
If you define a default state mask, it will be loaded into the object state make when you load the blend
file or when you run the game under the blenderplayer. However, when you run the game under Blender, 
the current selected state mask will be used as the startup state for the object. This allows you to test
specific state during the game design.

The controller display the state they belong to with a new button in the controller header. When you add
a new controller, it is added by default in the lowest enabled state. You can change the controller state 
by clicking on the button and selecting another state. If more than one state is enabled in the object
state mask, controllers are grouped by state for more readibility. 

The new Sta button in the sensor and actuator column header allows you to display only the sensors and 
actuators that are linked to visible controllers.

A new state actuator is available to modify the state during the game. It defines a bit mask and 
the operation to apply on the current object state mask:

Cpy: the bit mask is copied to the object state mask.
Add: the bits that set in the bit mask will be turned on in the object state mask.
Sub: the bits that set in the bit mask will be turned off in the object state mask.
Inv: the bits that set in the bit mask will be inverted in the objecyy state mask.

Notes
=====
- Although states have no name, a simply convention consists in using the name of the first controller 
  of the state as the state name. The GUI will support that convention by displaying as a hint the name
  of the first controller of the state when you move the mouse over a state bit of the object state mask
  or of the state actuator bit mask.
- Each object has a state mask and each object can have a state engine but if several objects are 
  part of a logical group, it is recommended to put the state engine only in the main object and to
  link the controllers of that object to the sensors and actuators of the different objects.
- When loading an old blend file, the state mask of all objects and controllers are initialized to 1 
  so that all the controllers belong to this single state. This ensures backward compatibility with 
  existing game.
- When the state actuator is activated at the same time as other actuators, these actuators are 
  guaranteed to execute before being eventually disabled due to the state change. This is useful for
  example to send a message or update a property at the time of changing the state.
- Sensors that depend on underlying resource won't reset fully when they are isolated. By the time they
  are acticated again, they will behave as follow:
  * keyboard sensor: keys already pressed won't be detected. The keyboard sensor is only sensitive 
    to new key press.
  * collision sensor: objects already colliding won't be detected. Only new collisions are 
    detected.
  * near and radar sensor: same as collision sensor.
2008-06-22 14:23:57 +00:00

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4.5 KiB
C++

/*
* $Id$
*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): none yet.
*
* ***** END GPL LICENSE BLOCK *****
* Actuator to toggle visibility/invisibility of objects
*/
#include "KX_StateActuator.h"
#include "KX_GameObject.h"
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
KX_StateActuator::KX_StateActuator(
SCA_IObject* gameobj,
int operation,
unsigned int mask,
PyTypeObject* T
)
: SCA_IActuator(gameobj,T),
m_operation(operation),
m_mask(mask)
{
// intentionally empty
}
KX_StateActuator::~KX_StateActuator(
void
)
{
// intentionally empty
}
CValue*
KX_StateActuator::GetReplica(
void
)
{
KX_StateActuator* replica = new KX_StateActuator(*this);
replica->ProcessReplica();
// this will copy properties and so on...
CValue::AddDataToReplica(replica);
return replica;
}
bool
KX_StateActuator::Update()
{
bool bNegativeEvent = IsNegativeEvent();
unsigned int objMask;
RemoveAllEvents();
if (bNegativeEvent) return false;
KX_GameObject *obj = (KX_GameObject*) GetParent();
objMask = obj->GetState();
switch (m_operation)
{
case OP_CPY:
objMask = m_mask;
break;
case OP_SET:
objMask |= m_mask;
break;
case OP_CLR:
objMask &= ~m_mask;
break;
case OP_NEG:
objMask ^= m_mask;
break;
default:
// unsupported operation, no nothing
return false;
}
obj->SetState(objMask);
return false;
}
/* ------------------------------------------------------------------------- */
/* Python functions */
/* ------------------------------------------------------------------------- */
/* Integration hooks ------------------------------------------------------- */
PyTypeObject
KX_StateActuator::Type = {
PyObject_HEAD_INIT(&PyType_Type)
0,
"KX_StateActuator",
sizeof(KX_StateActuator),
0,
PyDestructor,
0,
__getattr,
__setattr,
0, //&MyPyCompare,
__repr,
0, //&cvalue_as_number,
0,
0,
0,
0
};
PyParentObject
KX_StateActuator::Parents[] = {
&KX_StateActuator::Type,
&SCA_IActuator::Type,
&SCA_ILogicBrick::Type,
&CValue::Type,
NULL
};
PyMethodDef
KX_StateActuator::Methods[] = {
{"setOperation", (PyCFunction) KX_StateActuator::sPySetOperation,
METH_VARARGS, SetOperation_doc},
{"setMask", (PyCFunction) KX_StateActuator::sPySetMask,
METH_VARARGS, SetMask_doc},
{NULL,NULL} //Sentinel
};
PyObject*
KX_StateActuator::_getattr(
const STR_String& attr
)
{
_getattr_up(SCA_IActuator);
};
/* set operation ---------------------------------------------------------- */
char
KX_StateActuator::SetOperation_doc[] =
"setOperation(op)\n"
"\t - op : bit operation (0=Copy, 1=Set, 2=Clear, 3=Negate)"
"\tSet the type of bit operation to be applied on object state mask.\n"
"\tUse setMask() to specify the bits that will be modified.\n";
PyObject*
KX_StateActuator::PySetOperation(PyObject* self,
PyObject* args,
PyObject* kwds) {
int oper;
if(!PyArg_ParseTuple(args, "i", &oper)) {
return NULL;
}
m_operation = oper;
Py_Return;
}
/* set mask ---------------------------------------------------------- */
char
KX_StateActuator::SetMask_doc[] =
"setMask(mask)\n"
"\t - mask : bits that will be modified"
"\tSet the value that defines the bits that will be modified by the operation.\n"
"\tThe bits that are 1 in the value will be updated in the object state,\n"
"\tthe bits that are 0 are will be left unmodified expect for the Copy operation\n"
"\twhich copies the value to the object state.\n";
PyObject*
KX_StateActuator::PySetMask(PyObject* self,
PyObject* args,
PyObject* kwds) {
int mask;
if(!PyArg_ParseTuple(args, "i", &mask)) {
return NULL;
}
m_mask = mask;
Py_Return;
}