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| author | Alexander Gavrilov <angavrilov@gmail.com> | 2018-09-15 15:32:40 +0300 |
|---|---|---|
| committer | Alexander Gavrilov <angavrilov@gmail.com> | 2018-09-18 13:25:28 +0300 |
| commit | bf2a54b0584c1e568af7ecf67ae2a623bc5263fe (patch) | |
| tree | f123a9ca55d475dd676351d635bf944a31a27200 /source/blender/makesdna/DNA_anim_types.h | |
| 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/makesdna/DNA_anim_types.h')
| -rw-r--r-- | source/blender/makesdna/DNA_anim_types.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/source/blender/makesdna/DNA_anim_types.h b/source/blender/makesdna/DNA_anim_types.h index 22067b87ff8..edf137ca386 100644 --- a/source/blender/makesdna/DNA_anim_types.h +++ b/source/blender/makesdna/DNA_anim_types.h @@ -415,6 +415,8 @@ typedef struct ChannelDriver { char expression[256]; /* expression to compile for evaluation */ void *expr_comp; /* PyObject - compiled expression, don't save this */ + struct ParsedSimpleExpr *expr_simple; /* compiled simple arithmetic expression */ + float curval; /* result of previous evaluation */ float influence; /* influence of driver on result */ // XXX to be implemented... this is like the constraint influence setting |