text: 
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~~//
  // Arcane-FX for MIT Licensed Open Source version of Torque 3D from GarageGames
  // Copyright (C) 2015 Faust Logic, Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to
  // deal in the Software without restriction, including without limitation the
  // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  // sell copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  // IN THE SOFTWARE.
  //
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~~//
  
  #include "afx/arcaneFX.h"
  
  #include "afx/afxEffectWrapper.h"
  #include "afx/xm/afxXfmMod.h"
  
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~~//
  
  class afxXM_AltitudeConformData : public afxXM_WeightedBaseData
  {
    typedef afxXM_WeightedBaseData Parent;
  
  public:
    F32           height;
    bool          do_terrain;
    bool          do_interiors;
    U32           interior_types;
    U32           terrain_types;
    bool          do_freeze;
  
  public:
    /*C*/         afxXM_AltitudeConformData();
    /*C*/         afxXM_AltitudeConformData(const afxXM_AltitudeConformData&, bool = false);
  
    void          packData(BitStream* stream);
    void          unpackData(BitStream* stream);
    static void   initPersistFields();
  
    afxXM_Base*   create(afxEffectWrapper* fx, bool on_server);
  
    DECLARE_CONOBJECT(afxXM_AltitudeConformData);
    DECLARE_CATEGORY("AFX");
  };
  
  class afxXM_AltitudeConform : public afxXM_WeightedBase
  {
    typedef afxXM_WeightedBase Parent;
  
    afxXM_AltitudeConformData*  mConformData;
    SceneContainer*             mContainer;
    bool                        mDo_freeze;
    bool                        mIs_frozen;
    F32                         mTerrain_alt;
    F32                         mInterior_alt;
    Point3F                     mConformed_pos;
  
  public:
    /*C*/         afxXM_AltitudeConform(afxXM_AltitudeConformData*, afxEffectWrapper*, bool on_server);
  
    virtual void  updateParams(F32 dt, F32 elapsed, afxXM_Params& params);
  };
  
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~~//
  
  IMPLEMENT_CO_DATABLOCK_V1(afxXM_AltitudeConformData);
  
  ConsoleDocClass( afxXM_AltitudeConformData,
     "@brief An xmod datablock.\n\n"
  
     "@ingroup afxXMods\n"
     "@ingroup AFX\n"
     "@ingroup Datablocks\n"
  );
  
  afxXM_AltitudeConformData::afxXM_AltitudeConformData()
  {
    height = 0.0f;
    do_terrain = false;
    do_interiors = true;
    do_freeze = false;
    interior_types = InteriorLikeObjectType;
    terrain_types = TerrainObjectType | TerrainLikeObjectType;
  }
  
  afxXM_AltitudeConformData::afxXM_AltitudeConformData(const afxXM_AltitudeConformData& other, bool temp_clone) 
    : afxXM_WeightedBaseData(other, temp_clone)
  {
    height = other.height;
    do_terrain = other.do_terrain;
    do_interiors = other.do_interiors;
    do_freeze = other.do_freeze;
    interior_types = other.interior_types;
    terrain_types = other.terrain_types;
  }
  
  void afxXM_AltitudeConformData::initPersistFields()
  {
    addField("height",              TypeF32,      Offset(height, afxXM_AltitudeConformData),
      "...");
    addField("conformToTerrain",    TypeBool,     Offset(do_terrain, afxXM_AltitudeConformData),
      "...");
    addField("conformToInteriors",  TypeBool,     Offset(do_interiors, afxXM_AltitudeConformData),
      "...");
    addField("freeze",              TypeBool,     Offset(do_freeze, afxXM_AltitudeConformData),
      "...");
    addField("interiorTypes",       TypeS32,      Offset(interior_types, afxXM_AltitudeConformData),
      "...");
    addField("terrainTypes",        TypeS32,      Offset(terrain_types, afxXM_AltitudeConformData),
      "...");
  
    Parent::initPersistFields();
  }
  
  void afxXM_AltitudeConformData::packData(BitStream* stream)
  {
    Parent::packData(stream);
    stream->write(height);
    stream->writeFlag(do_terrain);
    stream->writeFlag(do_interiors);
    stream->writeFlag(do_freeze);
    stream->write(interior_types);
    stream->write(terrain_types);
  }
  
  void afxXM_AltitudeConformData::unpackData(BitStream* stream)
  {
    Parent::unpackData(stream);
    stream->read(&height);
    do_terrain = stream->readFlag();
    do_interiors = stream->readFlag();
    do_freeze = stream->readFlag();
    stream->read(&interior_types);
    stream->read(&terrain_types);
  }
  
  afxXM_Base* afxXM_AltitudeConformData::create(afxEffectWrapper* fx, bool on_server)
  {
    return new afxXM_AltitudeConform(this, fx, on_server);
  }
  
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//
  
  afxXM_AltitudeConform::afxXM_AltitudeConform(afxXM_AltitudeConformData* db, afxEffectWrapper* fxw, bool on_server) 
  : afxXM_WeightedBase(db, fxw) 
  { 
    mConformData = db;
    mContainer = (on_server) ? &gServerContainer : &gClientContainer;
    mDo_freeze = db->do_freeze;
    mIs_frozen = false;
    mTerrain_alt = -1.0f;
    mInterior_alt = -1.0f;
    mConformed_pos.zero();
  }
  
  void afxXM_AltitudeConform::updateParams(F32 dt, F32 elapsed, afxXM_Params& params)
  {
    if (mIs_frozen)
    {
      if (mTerrain_alt >= 0.0f)
        fx_wrapper->setTerrainAltitude(mTerrain_alt);
      if (mInterior_alt >= 0.0f)
        fx_wrapper->setInteriorAltitude(mInterior_alt);
      params.pos = mConformed_pos;
      return;
    }
  
    RayInfo rInfo1, rInfo2;
    bool hit1 = false, hit2 = false;
    bool hit1_is_interior = false;
  
    // find primary ground
    Point3F above_pos(params.pos); above_pos.z += 0.1f;
    Point3F below_pos(params.pos); below_pos.z -= 10000;
    hit1 = mContainer->castRay(above_pos, below_pos, mConformData->interior_types | mConformData->terrain_types, &rInfo1);
  
    // find secondary ground
    if (hit1 && rInfo1.object)
    {
      hit1_is_interior = ((rInfo1.object->getTypeMask() & mConformData->interior_types) != 0);
      U32 mask = (hit1_is_interior) ? mConformData->terrain_types : mConformData->interior_types;
      hit2 = mContainer->castRay(above_pos, below_pos, mask, &rInfo2);
    }
  
    if (hit1)
    {
      F32 wt_factor = calc_weight_factor(elapsed);
      F32 incoming_z = params.pos.z;
      F32 ground1_z = rInfo1.point.z + mConformData->height;
      F32 pos_z = ground1_z + (1.0f - wt_factor)*(incoming_z - ground1_z);
  
      if (hit1_is_interior)
      {
        mInterior_alt = incoming_z - pos_z;
        fx_wrapper->setInteriorAltitude(mInterior_alt);
        if (mConformData->do_interiors)
          params.pos.z = pos_z;
      }
      else
      {
        mTerrain_alt = incoming_z - pos_z;
        fx_wrapper->setTerrainAltitude(mTerrain_alt);
        if (mConformData->do_terrain)
          params.pos.z = pos_z;
      }
  
      if (hit2)
      {
        F32 ground2_z = rInfo2.point.z + mConformData->height;
        F32 z2 = ground2_z + (1.0f - wt_factor)*(incoming_z - ground2_z);
        if (hit1_is_interior)
        {
          mTerrain_alt = incoming_z - z2;
          fx_wrapper->setTerrainAltitude(mTerrain_alt);
        }
        else
        {
          mInterior_alt = incoming_z - z2;
          fx_wrapper->setInteriorAltitude(mInterior_alt);
        }
      }
  
      // check for case where interior is underground
      else if (hit1_is_interior)
      {
        RayInfo rInfo0;
        Point3F lookup_from_pos(params.pos); lookup_from_pos.z -= 0.1f;
        Point3F lookup_to_pos(params.pos); lookup_to_pos.z += 10000;
        if (mContainer->castRay(lookup_from_pos, lookup_to_pos, TerrainObjectType, &rInfo0))
        {
          F32 ground2_z = rInfo0.point.z + mConformData->height;
          F32 z2 = ground2_z + (1.0f - wt_factor)*(incoming_z - ground2_z);
          mTerrain_alt = z2 - incoming_z;
          fx_wrapper->setTerrainAltitude(mTerrain_alt);
        }
      }
  
      if (mDo_freeze)
      {
        mConformed_pos = params.pos;
        mIs_frozen = true;
      }
    }
  }
  
  //~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~//~~~~~~~~~~~~~~~~~~~~~//
  
  