Further fix for parented fluidsim objects

* The rotation values determined from ob->obmat have to be continuous as fluidsim interpolates between these values internally.

1 files changed, 18 insertions, 2 deletions

diff --git a/source/blender/editors/physics/physics_fluid.c b/source/blender/editors/physics/physics_fluid.c
index 210b2480d85..67d2184dc69 100644
--- a/source/blender/editors/physics/physics_fluid.c
+++ b/source/blender/editors/physics/physics_fluid.c
@@ -349,6 +349,16 @@ static void free_all_fluidobject_channels(ListBase *fobjects)
 	}
 }
 
+static void continuous_rotation(float *rot, const float *old_rot)
+{
+	*rot += (int)(*old_rot/360.f)*360.f;
+
+	if(*old_rot - *rot > 180.f)
+		*rot += 360.f;
+	else if(*old_rot - *rot < -180.f)
+		*rot -= 360.f;
+}
+
 static void fluid_init_all_channels(bContext *C, Object *UNUSED(fsDomain), FluidsimSettings *domainSettings, FluidAnimChannels *channels, ListBase *fobjects)
 {
 	Scene *scene = CTX_data_scene(C);
@@ -451,8 +461,14 @@ static void fluid_init_all_channels(bContext *C, Object *UNUSED(fsDomain), Fluid
 			/* init euler rotation values and convert to elbeem format */
 			/* get the rotation from ob->obmat rather than ob->rot to account for parent animations */
 			mat4_to_eul(rot_d, ob->obmat);
-			mul_v3_fl(rot_d, 180.f/M_PI);
-			sub_v3_v3v3(rot_d, rot_360, rot_d);
+			mul_v3_fl(rot_d, -180.f/M_PI);
+			if(i) {
+				/* the rotation values have to be continuous, so compare with previous rotation and adjust accordingly */
+				/* note: the unfortunate side effect of this is that it filters out rotations of over 180 degrees/frame */
+				continuous_rotation(rot_d, fobj->Rotation + 4*(i-1));
+				continuous_rotation(rot_d+1, fobj->Rotation + 4*(i-1)+1);
+				continuous_rotation(rot_d+2, fobj->Rotation + 4*(i-1)+2);
+			}
 			
 			set_channel(fobj->Translation, timeAtFrame, ob->loc, i, CHANNEL_VEC);
 			set_channel(fobj->Rotation, timeAtFrame, rot_d, i, CHANNEL_VEC);