Drivers: "Scripted Expression" drivers (i.e. PyDrivers) work again
Now it is possible to write a Python Expression using the variable names for driver targets (see mockup from initial commit) to substitute the appropriate values into the expression. In the __global__ namespace for PyDriver evaluation, the following modules are available: * __builtins__ - i.e. the builtin Python functions * bpy - new Python API * math or m - math module For example: Consider a driver with three targets, named: A, B, C Now, you could write an expression like: C if A < 5 else B or even: 2*C if A < 5 or A > 20 else m.PI*B Of course, you don't have to have three targets, the above was just an example. TODO: * Bring back way to load pydrivers.py * Blender.Noise equivalent would be nice to have P.S. I hope I haven't made any terrible Python API coding errors here (i.e. mem leaks, etc.)
This commit is contained in:
@@ -20,6 +20,7 @@
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#include "bpy_operator.h"
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#include "bpy_ui.h"
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#include "DNA_anim_types.h"
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#include "DNA_space_types.h"
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#include "DNA_text_types.h"
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@@ -29,6 +30,7 @@
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#include "BLI_string.h"
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#include "BKE_context.h"
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#include "BKE_fcurve.h"
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#include "BKE_text.h"
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#include "BPY_extern.h"
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@@ -415,3 +417,200 @@ void BPY_run_ui_scripts(bContext *C)
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#endif
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}
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/* ****************************************** */
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/* Drivers - PyExpression Evaluation */
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// XXX Hopefully I haven't committed any PyAPI coding sins here ;) - Aligorith, 2009Apr20
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/* for pydrivers (drivers using one-line Python expressions to express relationships between targets) */
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PyObject *bpy_pydriver_Dict = NULL;
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/* For faster execution we keep a special dictionary for pydrivers, with
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* the needed modules and aliases.
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*/
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static int bpy_pydriver_create_dict(void)
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{
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PyObject *d, *mod;
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/* validate namespace for driver evaluation */
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if (bpy_pydriver_Dict) return -1;
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d = PyDict_New();
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if (d == NULL)
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return -1;
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else
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bpy_pydriver_Dict = d;
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/* import some modules: builtins, bpy, math, (Blender.noise )*/
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PyDict_SetItemString(d, "__builtins__", PyEval_GetBuiltins());
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mod = PyImport_ImportModule("math");
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if (mod) {
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PyDict_Merge(d, PyModule_GetDict(mod), 0); /* 0 - dont overwrite existing values */
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/* Only keep for backwards compat! - just import all math into root, they are standard */
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PyDict_SetItemString(d, "math", mod);
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PyDict_SetItemString(d, "m", mod);
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Py_DECREF(mod);
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}
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/* add bpy to global namespace */
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mod= PyImport_ImportModuleLevel("bpy", NULL, NULL, NULL, 0);
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if (mod) {
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PyDict_SetItemString(bpy_pydriver_Dict, "bpy", mod);
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Py_DECREF(mod);
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}
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#if 0 // non existant yet
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mod = PyImport_ImportModule("Blender.Noise");
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if (mod) {
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PyDict_SetItemString(d, "noise", mod);
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PyDict_SetItemString(d, "n", mod);
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Py_DECREF(mod);
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} else {
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PyErr_Clear();
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}
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/* If there's a Blender text called pydrivers.py, import it.
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* Users can add their own functions to this module.
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*/
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if (G.f & G_DOSCRIPTLINKS) {
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mod = importText("pydrivers"); /* can also use PyImport_Import() */
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if (mod) {
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PyDict_SetItemString(d, "pydrivers", mod);
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PyDict_SetItemString(d, "p", mod);
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Py_DECREF(mod);
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} else {
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PyErr_Clear();
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}
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}
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#endif // non existant yet
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return 0;
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}
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/* Update function, it gets rid of pydrivers global dictionary, forcing
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* BPY_pydriver_eval to recreate it. This function is used to force
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* reloading the Blender text module "pydrivers.py", if available, so
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* updates in it reach pydriver evaluation.
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*/
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void BPY_pydriver_update(void)
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{
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PyGILState_STATE gilstate = PyGILState_Ensure();
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if (bpy_pydriver_Dict) { /* free the global dict used by pydrivers */
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PyDict_Clear(bpy_pydriver_Dict);
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Py_DECREF(bpy_pydriver_Dict);
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bpy_pydriver_Dict = NULL;
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}
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PyGILState_Release(gilstate);
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return;
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}
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/* error return function for BPY_eval_pydriver */
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static float pydriver_error(ChannelDriver *driver)
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{
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if (bpy_pydriver_Dict) { /* free the global dict used by pydrivers */
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PyDict_Clear(bpy_pydriver_Dict);
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Py_DECREF(bpy_pydriver_Dict);
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bpy_pydriver_Dict = NULL;
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}
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driver->flag |= DRIVER_FLAG_INVALID; /* py expression failed */
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fprintf(stderr, "\nError in Driver: The following Python expression failed:\n\t'%s'\n\n", driver->expression);
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PyErr_Print();
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return 0.0f;
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}
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/* This evals py driver expressions, 'expr' is a Python expression that
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* should evaluate to a float number, which is returned.
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*/
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float BPY_pydriver_eval (ChannelDriver *driver)
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{
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PyObject *driver_vars=NULL;
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PyObject *retval;
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PyGILState_STATE gilstate;
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DriverTarget *dtar;
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float result = 0.0f; /* default return */
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char *expr = NULL;
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short targets_ok= 1;
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/* sanity checks - should driver be executed? */
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if ((driver == NULL) /*|| (G.f & G_DOSCRIPTLINKS)==0*/)
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return result;
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/* get the py expression to be evaluated */
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expr = driver->expression;
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if ((expr == NULL) || (expr[0]=='\0'))
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return result;
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gilstate = PyGILState_Ensure();
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/* init global dictionary for py-driver evaluation settings */
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if (!bpy_pydriver_Dict) {
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if (bpy_pydriver_create_dict() != 0) {
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fprintf(stderr, "Pydriver error: couldn't create Python dictionary");
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PyGILState_Release(gilstate);
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return result;
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}
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}
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/* add target values to a py dictionary that we add to the drivers dict as 'd' */
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driver_vars = PyDict_New(); // XXX do we need to decref this?
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for (dtar= driver->targets.first; dtar; dtar= dtar->next) {
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PyObject *driver_arg = NULL;
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float tval = 0.0f;
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/* try to get variable value */
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tval= driver_get_target_value(driver, dtar);
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driver_arg= PyFloat_FromDouble((double)tval);
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if (driver_arg == NULL) continue;
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/* try to add to dictionary */
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if (PyDict_SetItemString(driver_vars, dtar->name, driver_arg)) {
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/* this target failed */
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if (targets_ok) {
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/* first one - print some extra info for easier identification */
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fprintf(stderr, "\nBPY_pydriver_eval() - Error while evaluating PyDriver:\n");
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targets_ok= 0;
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}
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fprintf(stderr, "\tBPY_pydriver_eval() - couldn't add variable '%s' to namespace \n", dtar->name);
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PyErr_Print();
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}
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}
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/* execute expression to get a value */
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retval = PyRun_String(expr, Py_eval_input, bpy_pydriver_Dict, driver_vars);
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/* decref the driver vars first... */
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Py_DECREF(driver_vars);
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/* process the result */
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if (retval == NULL) {
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result = pydriver_error(driver);
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PyGILState_Release(gilstate);
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return result;
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}
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result = (float)PyFloat_AsDouble(retval);
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Py_DECREF(retval);
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if ((result == -1) && PyErr_Occurred()) {
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result = pydriver_error(driver);
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PyGILState_Release(gilstate);
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return result;
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}
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/* all fine, make sure the "invalid expression" flag is cleared */
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driver->flag &= ~DRIVER_FLAG_INVALID;
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PyGILState_Release(gilstate);
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return result;
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}
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