This commit extends the technique of dynamic linked list to the logic
system to eliminate as much as possible temporaries, map lookup or
full scan. The logic engine is now free of memory allocation, which is
an important stability factor.
The overhead of the logic system is reduced by a factor between 3 and 6
depending on the logic setup. This is the speed-up you can expect on
a logic setup using simple bricks. Heavy bricks like python controllers
and ray sensors will still take about the same time to execute so the
speed up will be less important.
The core of the logic engine has been much reworked but the functionality
is still the same except for one thing: the priority system on the
execution of controllers. The exact same remark applies to actuators but
I'll explain for controllers only:
Previously, it was possible, with the "executePriority" attribute to set
a controller to run before any other controllers in the game. Other than
that, the sequential execution of controllers, as defined in Blender was
guaranteed by default.
With the new system, the sequential execution of controllers is still
guaranteed but only within the controllers of one object. the user can
no longer set a controller to run before any other controllers in the
game. The "executePriority" attribute controls the execution of controllers
within one object. The priority is a small number starting from 0 for the
first controller and incrementing for each controller.
If this missing feature is a must, a special method can be implemented
to set a controller to run before all other controllers.
Other improvements:
- Systematic use of reference in parameter passing to avoid unnecessary data copy
- Use pre increment in iterator instead of post increment to avoid temporary allocation
- Use const char* instead of STR_String whenever possible to avoid temporary allocation
- Fix reference counting bugs (memory leak)
- Fix a crash in certain cases of state switching and object deletion
- Minor speed up in property sensor
- Removal of objects during the game is a lot faster
I added module clearing before there was checks for invalid python objects, so now its not needed for BGE Builtin types at least.
also made the builtin modules get re-used if they already exist and clear all user modules when the game engine finishes so with Module-Py-Controllers the referenced modules are at least up to date when pressing Pkey.
This changes how the BGE classes and Python work together, which hasnt changed since blender went opensource.
The main difference is PyObjectPlus - the base class for most game engine classes, no longer inherit from PyObject, and cannot be cast to a PyObject.
This has the advantage that the BGE does not have to keep 2 reference counts valid for C++ and Python.
Previously C++ classes would never be freed while python held a reference, however this reference could be problematic eg: a GameObject that isnt in a scene anymore should not be used by python, doing so could even crash blender in some cases.
Instead PyObjectPlus has a member "PyObject *m_proxy" which is lazily initialized when python needs it. m_proxy reference counts are managed by python, though it should never be freed while the C++ class exists since it holds a reference to avoid making and freeing it all the time.
When the C++ class is free'd it sets the m_proxy reference to NULL, If python accesses this variable it will raise a RuntimeError, (check the isValid attribute to see if its valid without raising an error).
- This replaces the m_zombie bool and IsZombie() tests added recently.
In python return values that used to be..
return value->AddRef();
Are now
return value->GetProxy();
or...
return value->NewProxy(true); // true means python owns this C++ value which will be deleted when the PyObject is freed
There were also some problems with int to python conversion
- assigning a PyLong to a KX_GameObject from python would raise an error
- PyLong were coerced into floats when used with internal CValue arithmetic
Changes...
- PyLong is converted into CIntValue for coercing and assigning from python
- CValue's generic GetNumber() function returns a double rather then a float.
- Print an error when a PyType cant be coerced into a CValue
Tested with python, expressions and property sensor.
- variables that shadow vers declared earlier
- Py_Fatal print an error to the stderr
- gcc was complaining about the order of initialized vars (for classes)
- const return values for ints and bools didnt do anything.
- braces for ambiguous if statements
scene.getObjectList()[-1] works like a python sequence.
removed some STR_String creation that was only used to do comparisons, in a simple expressions benchmark this made logic use 4% less overall.
* removed macros that were not used much, some misleading.
* removed error string setting calls that overwrote the error set by PyArg_ParseTuple with a less useful one.
* use python macros Py_RETURN_NONE, Py_RETURN_TRUE, Py_RETURN_FALSE
