Followup to Bugfix #6435 by Ton.

Added sensible way in calculateTransformCenter to report an error (including empty selection).

3 files changed, 21 insertions, 7 deletions

diff --git a/source/blender/include/BIF_transform.h b/source/blender/include/BIF_transform.h
index 6d1b4e32658..3b5eeb6f35a 100755
--- a/source/blender/include/BIF_transform.h
+++ b/source/blender/include/BIF_transform.h
@@ -67,8 +67,11 @@ void initTransform(int mode, int context);
 void Transform(void);
 void Mirror(short mode);
 
-/* Standalone call to get the transformation center corresponding to the current situation */
-void calculateTransformCenter(int centerMode, float *vec);
+/* Standalone call to get the transformation center corresponding to the current situation
+ * returns 1 if successful, 0 otherwise (usually means there's no selection)
+ * (if 0 is returns, *vec is unmodified) 
+ * */
+int calculateTransformCenter(int centerMode, float *vec);
 
 struct TransInfo;
 struct ScrArea;
diff --git a/source/blender/src/transform.c b/source/blender/src/transform.c
index 7067d1e9003..3bd63fed07a 100755
--- a/source/blender/src/transform.c
+++ b/source/blender/src/transform.c
@@ -756,8 +756,9 @@ static void transformEvent(unsigned short event, short val) {
 	}
 }
 
-void calculateTransformCenter(int centerMode, float *vec)
+int calculateTransformCenter(int centerMode, float *vec)
 {
+	int success = 1;
 	checkFirstTime();
 
 	Trans.state = TRANS_RUNNING;
@@ -772,15 +773,24 @@ void calculateTransformCenter(int centerMode, float *vec)
 
 	Trans.around = centerMode; 			// override userdefined mode
 
-	calculateCenter(&Trans);
-
-	// Copy center from constraint center. Transform center can be local	
-	VECCOPY(vec, Trans.con.center);
+	if (Trans.total == 0) {
+		success = 0;
+	}
+	else {
+		success = 1;
+		
+		calculateCenter(&Trans);
 	
+		// Copy center from constraint center. Transform center can be local	
+		VECCOPY(vec, Trans.con.center);
+	}
+
 	postTrans(&Trans);
 
 	/* aftertrans does insert ipos and action channels, and clears base flags, doesnt read transdata */
 	special_aftertrans_update(&Trans);
+	
+	return success;
 }
 
 void initTransform(int mode, int context) {
diff --git a/source/blender/src/view.c b/source/blender/src/view.c
index ad8aa2bd38a..ef6a589e541 100644
--- a/source/blender/src/view.c
+++ b/source/blender/src/view.c
@@ -578,6 +578,7 @@ void viewmove(int mode)
 		
 		VECCOPY(ofs, G.vd->ofs);
 		
+		/* If there's no selection, obofs is unmodified, so <0,0,0> */
 		calculateTransformCenter(V3D_CENTROID, obofs);
 		VecMulf(obofs, -1.0f);
 	}