Fix bug in new cublic spline sphere sweep bounding box computations.

Author: c-lipka

changes.txt

@@ -24,6 +24,19 @@ should be located in the same directory as this file is.
 ------------------------------------------------------------------------------
 
 
+Changes between 3.7.1-beta.6 and 3.7.1-beta.7
+=============================================
+
+This version is essentially a hotfix for some issues with beta.6.
+
+Fixed or Mitigated Bugs
+-----------------------
+
+Miscellaneous:
+
+  - Fixed a bug in the new `cubic_spline` sphere sweep bounding code.
+
+
 Changes between 3.7.1-beta.5 and 3.7.1-beta.6
 =============================================
 

revision.txt

@@ -26,10 +26,18 @@ Notes:
   http://news.povray.org/[email protected]
 ------------------------------------------------------------------------------
 
+------------------------------------------------------------------------------
+POV-Ray v3.7.1-beta.7
+------------------------------------------------------------------------------
+
 ------------------------------------------------------------------------------
 POV-Ray v3.7.1-beta.6
 ------------------------------------------------------------------------------
 
+Commit 6345350 on 2017-05-07 by Christoph Lipka
+
+    Update change log.
+
 Commit ab22c3e on 2017-05-07 by Christoph Lipka
 
     Fix for a bug in recent commit ce8b193.

source/core/shape/spheresweep.cpp

@@ -1271,8 +1271,8 @@ void SphereSweep::Compute_BBox()
             tempSphere[0]        = Modeling_Sphere[i];
             tempSphere[1].Center = Modeling_Sphere[i].Center + (Modeling_Sphere[i+1].Center - Modeling_Sphere[i-1].Center) / 6;
             tempSphere[1].Radius = Modeling_Sphere[i].Radius + (Modeling_Sphere[i+1].Radius - Modeling_Sphere[i-1].Radius) / 6;
-            tempSphere[2].Center = Modeling_Sphere[i+1].Center + (Modeling_Sphere[i].Center - Modeling_Sphere[i+1].Center) / 6;
-            tempSphere[2].Radius = Modeling_Sphere[i+1].Radius + (Modeling_Sphere[i].Radius - Modeling_Sphere[i+1].Radius) / 6;
+            tempSphere[2].Center = Modeling_Sphere[i+1].Center + (Modeling_Sphere[i].Center - Modeling_Sphere[i+2].Center) / 6;
+            tempSphere[2].Radius = Modeling_Sphere[i+1].Radius + (Modeling_Sphere[i].Radius - Modeling_Sphere[i+2].Radius) / 6;
             tempSphere[3]        = Modeling_Sphere[i+1];
 
             // From the Bezier-style control spheres, compute the bounding box.