Freestyle: Fix for a potential infinite loop in stroke resampling by vertex count.

Changes were made in Stroke::Resample(int) in C++ to prevent a potential infinite loop
caused by an inconsistency between Stroke::_Length and the stroke length computed
based on stroke vertices.  Such a stroke length inconsistency is usually caused by missing
calls of Stroke::UpdateLength() (i.e., API implementation bugs), but also may occur due
to scripting errors in user-defined style modules.  This commit is meant to help script
writters to identify the latter error cases.  Now Stroke.resample(int) may raise a runtime
error to signal an error condition.

1 files changed, 8 insertions, 2 deletions

diff --git a/source/blender/freestyle/intern/python/Interface1D/BPy_Stroke.cpp b/source/blender/freestyle/intern/python/Interface1D/BPy_Stroke.cpp
index 7110eef9036..aa8c90cfd24 100644
--- a/source/blender/freestyle/intern/python/Interface1D/BPy_Stroke.cpp
+++ b/source/blender/freestyle/intern/python/Interface1D/BPy_Stroke.cpp
@@ -151,10 +151,16 @@ static PyObject *Stroke_resample(BPy_Stroke *self, PyObject *args, PyObject *kwd
 	float f;
 
 	if (PyArg_ParseTupleAndKeywords(args, kwds, "i", (char **)kwlist_1, &i)) {
-		self->s->Resample(i);
+		if (self->s->Resample(i) < 0) {
+			PyErr_SetString(PyExc_RuntimeError, "Stroke resampling (by vertex count) failed");
+			return NULL;
+		}
 	}
 	else if (PyErr_Clear(), PyArg_ParseTupleAndKeywords(args, kwds, "f", (char **)kwlist_2, &f)) {
-		self->s->Resample(f);
+		if (self->s->Resample(f) < 0) {
+			PyErr_SetString(PyExc_RuntimeError, "Stroke resampling (by vertex interval) failed");
+			return NULL;
+		}
 	}
 	else {
 		PyErr_SetString(PyExc_TypeError, "invalid argument");