diff options
author | Alexander Gavrilov <angavrilov@gmail.com> | 2018-09-15 15:32:40 +0300 |
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committer | Alexander Gavrilov <angavrilov@gmail.com> | 2018-09-18 13:25:28 +0300 |
commit | bf2a54b0584c1e568af7ecf67ae2a623bc5263fe (patch) | |
tree | f123a9ca55d475dd676351d635bf944a31a27200 /source/blender/blenkernel/intern/fcurve.c | |
parent | 34ee9ab97c0cf629987f8f3f72b529ca7e73e027 (diff) |
Support evaluating simple driver expressions without Python interpreter.
Recently @sergey found that hard-coding evaluation of certain very
common driver expressions without calling the Python interpreter
produces a 30-40% performance improvement. Since hard-coding is
obviously not suitable for production, I implemented a proper
parser and interpreter for simple arithmetic expressions in C.
The evaluator supports +, -, *, /, (), ==, !=, <, <=, >, >=,
and, or, not, ternary if; driver variables, frame, pi, True, False,
and a subset of standard math functions that seem most useful.
Booleans are represented as numbers, since within the supported
operation set it seems to be impossible to distinguish True/False
from 1.0/0.0. Boolean operations properly implement lazy evaluation
with jumps, and comparisons support chaining like 'a < b < c...'.
Expressions are parsed into a very simple stack machine program
that can then be safely evaluated in multiple threads.
Reviewers: sergey, campbellbarton
Differential Revision: https://developer.blender.org/D3698
Diffstat (limited to 'source/blender/blenkernel/intern/fcurve.c')
-rw-r--r-- | source/blender/blenkernel/intern/fcurve.c | 143 |
1 files changed, 131 insertions, 12 deletions
diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c index bf516a6b739..629307d6cc2 100644 --- a/source/blender/blenkernel/intern/fcurve.c +++ b/source/blender/blenkernel/intern/fcurve.c @@ -49,6 +49,8 @@ #include "BLI_threads.h" #include "BLI_string_utils.h" #include "BLI_utildefines.h" +#include "BLI_simple_expr.h" +#include "BLI_alloca.h" #include "BLT_translation.h" @@ -65,6 +67,8 @@ #include "RNA_access.h" +#include "atomic_ops.h" + #ifdef WITH_PYTHON #include "BPY_extern.h" #endif @@ -1694,11 +1698,8 @@ void driver_free_variable_ex(ChannelDriver *driver, DriverVar *dvar) /* remove and free the driver variable */ driver_free_variable(&driver->variables, dvar); -#ifdef WITH_PYTHON /* since driver variables are cached, the expression needs re-compiling too */ - if (driver->type == DRIVER_TYPE_PYTHON) - driver->flag |= DRIVER_FLAG_RENAMEVAR; -#endif + BKE_driver_invalidate_expression(driver, false, true); } /* Copy driver variables from src_vars list to dst_vars list */ @@ -1835,11 +1836,8 @@ DriverVar *driver_add_new_variable(ChannelDriver *driver) /* set the default type to 'single prop' */ driver_change_variable_type(dvar, DVAR_TYPE_SINGLE_PROP); -#ifdef WITH_PYTHON /* since driver variables are cached, the expression needs re-compiling too */ - if (driver->type == DRIVER_TYPE_PYTHON) - driver->flag |= DRIVER_FLAG_RENAMEVAR; -#endif + BKE_driver_invalidate_expression(driver, false, true); /* return the target */ return dvar; @@ -1868,6 +1866,8 @@ void fcurve_free_driver(FCurve *fcu) BPY_DECREF(driver->expr_comp); #endif + BLI_simple_expr_free(driver->expr_simple); + /* free driver itself, then set F-Curve's point to this to NULL (as the curve may still be used) */ MEM_freeN(driver); fcu->driver = NULL; @@ -1885,6 +1885,7 @@ ChannelDriver *fcurve_copy_driver(const ChannelDriver *driver) /* copy all data */ ndriver = MEM_dupallocN(driver); ndriver->expr_comp = NULL; + ndriver->expr_simple = NULL; /* copy variables */ BLI_listbase_clear(&ndriver->variables); /* to get rid of refs to non-copied data (that's still used on original) */ @@ -1894,6 +1895,124 @@ ChannelDriver *fcurve_copy_driver(const ChannelDriver *driver) return ndriver; } +/* Driver Expression Evaluation --------------- */ + +static ParsedSimpleExpr *driver_compile_simple_expr_impl(ChannelDriver *driver) +{ + /* Prepare parameter names. */ + int num_vars = BLI_listbase_count(&driver->variables); + const char **names = BLI_array_alloca(names, num_vars + 1); + int i = 0; + + names[i++] = "frame"; + + for (DriverVar *dvar = driver->variables.first; dvar; dvar = dvar->next) { + names[i++] = dvar->name; + } + + return BLI_simple_expr_parse(driver->expression, num_vars + 1, names); +} + +static bool driver_evaluate_simple_expr(ChannelDriver *driver, ParsedSimpleExpr *expr, float *result, float time) +{ + /* Prepare parameter values. */ + int num_vars = BLI_listbase_count(&driver->variables); + double *vars = BLI_array_alloca(vars, num_vars + 1); + int i = 0; + + vars[i++] = time; + + for (DriverVar *dvar = driver->variables.first; dvar; dvar = dvar->next) { + vars[i++] = driver_get_variable_value(driver, dvar); + } + + /* Evaluate expression. */ + double result_val; + eSimpleExpr_EvalStatus status = BLI_simple_expr_evaluate(expr, &result_val, num_vars + 1, vars); + const char *message; + + switch (status) { + case SIMPLE_EXPR_SUCCESS: + if (isfinite(result_val)) { + *result = (float)result_val; + } + return true; + + case SIMPLE_EXPR_DIV_BY_ZERO: + case SIMPLE_EXPR_MATH_ERROR: + message = (status == SIMPLE_EXPR_DIV_BY_ZERO) ? "Division by Zero" : "Math Domain Error"; + fprintf(stderr, "\n%s in Driver: '%s'\n", message, driver->expression); + + driver->flag |= DRIVER_FLAG_INVALID; + return true; + + default: + /* arriving here means a bug, not user error */ + printf("Error: simple driver expression evaluation failed: '%s'\n", driver->expression); + return false; + } +} + +/* Compile and cache the driver expression if necessary, with thread safety. */ +static bool driver_compile_simple_expr(ChannelDriver *driver) +{ + if (driver->expr_simple != NULL) { + return true; + } + + if (driver->type != DRIVER_TYPE_PYTHON) { + return false; + } + + /* It's safe to parse in multiple threads; at worst it'll + * waste some effort, but in return avoids mutex contention. */ + ParsedSimpleExpr *expr = driver_compile_simple_expr_impl(driver); + + /* Store the result if the field is still NULL, or discard + * it if another thread got here first. */ + if (atomic_cas_ptr((void**)&driver->expr_simple, NULL, expr) != NULL) { + BLI_simple_expr_free(expr); + } + + return true; +} + +/* Try using the simple expression evaluator to compute the result of the driver. + * On success, stores the result and returns true; on failure result is set to 0. */ +static bool driver_try_evaluate_simple_expr(ChannelDriver *driver, ChannelDriver *driver_orig, float *result, float time) +{ + *result = 0.0f; + + return driver_compile_simple_expr(driver_orig) && + BLI_simple_expr_is_valid(driver_orig->expr_simple) && + driver_evaluate_simple_expr(driver, driver_orig->expr_simple, result, time); +} + +/* Check if the expression in the driver conforms to the simple subset. */ +bool BKE_driver_has_simple_expression(ChannelDriver *driver) +{ + return driver_compile_simple_expr(driver) && BLI_simple_expr_is_valid(driver->expr_simple); +} + +/* Reset cached compiled expression data */ +void BKE_driver_invalidate_expression(ChannelDriver *driver, bool expr_changed, bool varname_changed) +{ + if (expr_changed || varname_changed) { + BLI_simple_expr_free(driver->expr_simple); + driver->expr_simple = NULL; + } + +#ifdef WITH_PYTHON + if (expr_changed) { + driver->flag |= DRIVER_FLAG_RECOMPILE; + } + + if (varname_changed) { + driver->flag |= DRIVER_FLAG_RENAMEVAR; + } +#endif +} + /* Driver Evaluation -------------------------- */ /* Evaluate a Driver Variable to get a value that contributes to the final */ @@ -1997,14 +2116,14 @@ float evaluate_driver(PathResolvedRNA *anim_rna, ChannelDriver *driver, ChannelD } case DRIVER_TYPE_PYTHON: /* expression */ { -#ifdef WITH_PYTHON /* check for empty or invalid expression */ if ( (driver_orig->expression[0] == '\0') || (driver_orig->flag & DRIVER_FLAG_INVALID) ) { driver->curval = 0.0f; } - else { + else if (!driver_try_evaluate_simple_expr(driver, driver_orig, &driver->curval, evaltime)) { +#ifdef WITH_PYTHON /* this evaluates the expression using Python, and returns its result: * - on errors it reports, then returns 0.0f */ @@ -2013,10 +2132,10 @@ float evaluate_driver(PathResolvedRNA *anim_rna, ChannelDriver *driver, ChannelD driver->curval = BPY_driver_exec(anim_rna, driver, driver_orig, evaltime); BLI_mutex_unlock(&python_driver_lock); - } #else /* WITH_PYTHON*/ - UNUSED_VARS(anim_rna, evaltime); + UNUSED_VARS(anim_rna, evaltime); #endif /* WITH_PYTHON*/ + } break; } default: |