* Documented that get/setOrientation use an inverted rotation matrix

* OB prefix is needed when specifying the object for the Message Actuator, this is very bad since other object fields in the BGE dont need this prefix - a real fix would need do_versions to keep old files running.
* RotationMatrix was all nans if the rotation vector axis was 0,0,0, Changed so in this case just return a matrix that doesn't rotate anything,

spent some angry hours to find these issues, maybe this will save others the hassle ;)

3 files changed, 30 insertions, 25 deletions

diff --git a/source/blender/python/api2_2x/Mathutils.c b/source/blender/python/api2_2x/Mathutils.c
index e63fc5ef38f..87ac3e3e6ba 100644
--- a/source/blender/python/api2_2x/Mathutils.c
+++ b/source/blender/python/api2_2x/Mathutils.c
@@ -725,28 +725,33 @@ PyObject *M_Mathutils_RotationMatrix(PyObject * self, PyObject * args)
 		vec->vec[0] /= norm;
 		vec->vec[1] /= norm;
 		vec->vec[2] /= norm;
-
-		//create matrix
-		cosAngle = (float) cos(angle);
-		sinAngle = (float) sin(angle);
-		mat[0] = ((vec->vec[0] * vec->vec[0]) * (1 - cosAngle)) +
-			cosAngle;
-		mat[1] = ((vec->vec[0] * vec->vec[1]) * (1 - cosAngle)) +
-			(vec->vec[2] * sinAngle);
-		mat[2] = ((vec->vec[0] * vec->vec[2]) * (1 - cosAngle)) -
-			(vec->vec[1] * sinAngle);
-		mat[3] = ((vec->vec[0] * vec->vec[1]) * (1 - cosAngle)) -
-			(vec->vec[2] * sinAngle);
-		mat[4] = ((vec->vec[1] * vec->vec[1]) * (1 - cosAngle)) +
-			cosAngle;
-		mat[5] = ((vec->vec[1] * vec->vec[2]) * (1 - cosAngle)) +
-			(vec->vec[0] * sinAngle);
-		mat[6] = ((vec->vec[0] * vec->vec[2]) * (1 - cosAngle)) +
-			(vec->vec[1] * sinAngle);
-		mat[7] = ((vec->vec[1] * vec->vec[2]) * (1 - cosAngle)) -
-			(vec->vec[0] * sinAngle);
-		mat[8] = ((vec->vec[2] * vec->vec[2]) * (1 - cosAngle)) +
-			cosAngle;
+		
+		if (isnan(vec->vec[0]) || isnan(vec->vec[1]) || isnan(vec->vec[2])) {
+			/* zero length vector, return an identity matrix, could also return an error */
+			mat[0]= mat[4] = mat[8] = 1.0f;
+		} else {	
+			/* create matrix */
+			cosAngle = (float) cos(angle);
+			sinAngle = (float) sin(angle);
+			mat[0] = ((vec->vec[0] * vec->vec[0]) * (1 - cosAngle)) +
+				cosAngle;
+			mat[1] = ((vec->vec[0] * vec->vec[1]) * (1 - cosAngle)) +
+				(vec->vec[2] * sinAngle);
+			mat[2] = ((vec->vec[0] * vec->vec[2]) * (1 - cosAngle)) -
+				(vec->vec[1] * sinAngle);
+			mat[3] = ((vec->vec[0] * vec->vec[1]) * (1 - cosAngle)) -
+				(vec->vec[2] * sinAngle);
+			mat[4] = ((vec->vec[1] * vec->vec[1]) * (1 - cosAngle)) +
+				cosAngle;
+			mat[5] = ((vec->vec[1] * vec->vec[2]) * (1 - cosAngle)) +
+				(vec->vec[0] * sinAngle);
+			mat[6] = ((vec->vec[0] * vec->vec[2]) * (1 - cosAngle)) +
+				(vec->vec[1] * sinAngle);
+			mat[7] = ((vec->vec[1] * vec->vec[2]) * (1 - cosAngle)) -
+				(vec->vec[0] * sinAngle);
+			mat[8] = ((vec->vec[2] * vec->vec[2]) * (1 - cosAngle)) +
+				cosAngle;
+		}
 	} else {
 		return EXPP_ReturnPyObjError(PyExc_AttributeError,
 			"Mathutils.RotationMatrix(): unrecognizable axis of rotation type - expected x,y,z or r\n");
diff --git a/source/blender/src/buttons_logic.c b/source/blender/src/buttons_logic.c
index 59fedf04e30..b6877b2e2b7 100644
--- a/source/blender/src/buttons_logic.c
+++ b/source/blender/src/buttons_logic.c
@@ -2149,7 +2149,7 @@ static short draw_actuatorbuttons(bActuator *act, uiBlock *block, short xco, sho
 		uiDefBut(block, TEX, 1, "To: ",
 			(xco+10), (yco-(myline++*24)), (width-20), 19,
 			&ma->toPropName, 0, 31, 0, 0,
-			"Optional send message to objects with this name only"
+			"Optional send message to objects with this name only (Prefix name with OB)"
 			", or empty to broadcast");
 
 #endif
diff --git a/source/gameengine/PyDoc/KX_GameObject.py b/source/gameengine/PyDoc/KX_GameObject.py
index 678df59e4a9..ff55f975543 100644
--- a/source/gameengine/PyDoc/KX_GameObject.py
+++ b/source/gameengine/PyDoc/KX_GameObject.py
@@ -50,7 +50,7 @@ class KX_GameObject:
 		"""
 		Sets the game object's orientation.
 		
-		@type orn: 3x3 rotation matrix, or Quaternion.
+		@type orn: 3x3 inverted rotation matrix, or Quaternion.
 		@param orn: a rotation matrix specifying the new rotation.
 		"""
 	def alignAxisToVect(vect, axis):
@@ -69,7 +69,7 @@ class KX_GameObject:
 		"""
 		Gets the game object's orientation.
 		
-		@rtype: 3x3 rotation matrix
+		@rtype: 3x3 inverted rotation matrix
 		@return: The game object's rotation matrix
 		"""
 	def getLinearVelocity(local):