Fix #409.

This clarifies that the "wind object" on the water modifier also controls
the water height. The user visible field has been renamed to "Reference
Object" and the description has been updated to match what is actually
happening. We no longer encode any value for the wind direction into the
PRP if a reference object is specified. Instead, we export the object's
CI and let the engine figure it out at runtime.

korman/properties/modifiers/water.py

@@ -182,8 +182,8 @@ class PlasmaWaterModifier(idprops.IDPropMixin, PlasmaModifierProperties, bpy.typ
     bl_description = "Basic water properties"
     bl_object_types = {"MESH"}
 
-    wind_object = PointerProperty(name="Wind Object",
+    wind_object = PointerProperty(name="Reference Object",
-                                  description="Object whose Y axis represents the wind direction",
+                                  description="Object whose Y axis represents the wind direction and whose Z axis represents the water height",
                                   type=bpy.types.Object,
                                   poll=idprops.poll_empty_objects)
     wind_speed = FloatProperty(name="Wind Speed",
@@ -244,15 +244,9 @@ class PlasmaWaterModifier(idprops.IDPropMixin, PlasmaModifierProperties, bpy.typ
 
     def export(self, exporter, bo, so):
         waveset = exporter.mgr.find_create_object(plWaveSet7, name=bo.name, so=so)
-        if self.wind_object:
+        if self.wind_object is not None:
-            if exporter.has_coordiface(self.wind_object):
             waveset.refObj = exporter.mgr.find_create_key(plSceneObject, bl=self.wind_object)
             waveset.setFlag(plWaveSet7.kHasRefObject, True)
-
-            # This is much like what happened in PyPRP
-            speed = self.wind_speed
-            matrix = self.wind_object.matrix_world
-            wind_dir = hsVector3(matrix[1][0] * speed, matrix[1][1] * speed, matrix[1][2] * speed)
         else:
             # Stolen shamelessly from PyPRP
             wind_dir = hsVector3(0.0871562, 0.996195, 0.0)
@@ -296,6 +290,10 @@ class PlasmaWaterModifier(idprops.IDPropMixin, PlasmaModifierProperties, bpy.typ
         if not mods.water_shore.enabled:
             mods.water_shore.convert_default(state)
 
+    def harvest_actors(self):
+        if self.wind_object is not None:
+            yield self.wind_object.name
+
     @classmethod
     def _idprop_mapping(cls):
         return {"wind_object": "wind_object_name",