[Bf-blender-cvs] [3fe7aac] master: Curve Fitting: circular fit could give NAN handles

[Campbell Barton]

Commit: 3fe7aacdf7f87ef9293ae4d8c4ce1dd9373e7011
Author: Campbell Barton
Date:   Sun Jul 31 13:55:50 2016 +1000
Branches: master
https://developer.blender.org/rB3fe7aacdf7f87ef9293ae4d8c4ce1dd9373e7011

Curve Fitting: circular fit could give NAN handles

Fitting lines that exactly double back on themselves could give NAN length handles.

===================================================================

M	extern/curve_fit_nd/intern/curve_fit_cubic.c

===================================================================

diff --git a/extern/curve_fit_nd/intern/curve_fit_cubic.c b/extern/curve_fit_nd/intern/curve_fit_cubic.c
index 24b216d..9c8ebcd 100644
--- a/extern/curve_fit_nd/intern/curve_fit_cubic.c
+++ b/extern/curve_fit_nd/intern/curve_fit_cubic.c
@@ -742,7 +742,11 @@ static void cubic_from_points(
 	    !(alpha_r >= 0.0))
 	{
 #ifdef USE_CIRCULAR_FALLBACK
-		alpha_l = alpha_r = points_calc_cubic_scale(p0, p3, tan_l, tan_r, points_offset_coords_length, dims);
+		double alpha_test = points_calc_cubic_scale(p0, p3, tan_l, tan_r, points_offset_coords_length, dims);
+		if (!isfinite(alpha_test)) {
+			alpha_test = len_vnvn(p0, p3, dims) / 3.0;
+		}
+		alpha_l = alpha_r = alpha_test;
 #else
 		alpha_l = alpha_r = len_vnvn(p0, p3, dims) / 3.0;
 #endif
@@ -804,7 +808,11 @@ static void cubic_from_points(
 		    p2_dist_sq > dist_sq_max)
 		{
 #ifdef USE_CIRCULAR_FALLBACK
-			alpha_l = alpha_r = points_calc_cubic_scale(p0, p3, tan_l, tan_r, points_offset_coords_length, dims);
+			double alpha_test = points_calc_cubic_scale(p0, p3, tan_l, tan_r, points_offset_coords_length, dims);
+			if (!isfinite(alpha_test)) {
+				alpha_test = len_vnvn(p0, p3, dims) / 3.0;
+			}
+			alpha_l = alpha_r = alpha_test;
 #else
 			alpha_l = alpha_r = len_vnvn(p0, p3, dims) / 3.0;
 #endif