ProjectedGrid.cpp

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/*
--------------------------------------------------------------------------------
This source file is part of Hydrax.
Visit ---
 
Copyright (C) 2008 Xavier Verguín González <xavierverguin@hotmail.com>
                                           <xavyiy@gmail.com>
 
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
 
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 
You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
--------------------------------------------------------------------------------
 
Based on the Projected Grid concept from Claes Johanson thesis:
http://graphics.cs.lth.se/theses/projects/projgrid/
and Ren Cheng Ogre3D implementation:
http://www.cnblogs.com/ArenAK/archive/2007/11/07/951713.html
--------------------------------------------------------------------------------
*/
 
#include <ProjectedGrid.h>
 
#define _def_MaxFarClipDistance 99999
 
namespace Hydrax{namespace Module
{
    Mesh::VertexType _PG_getVertexTypeFromNormalMode(const MaterialManager::NormalMode& NormalMode)
    {
        if (NormalMode == MaterialManager::NM_VERTEX)
        {
            return Mesh::VT_POS_NORM;
        }
 
        // NM_RTT
        return Mesh::VT_POS;
    }
 
    Ogre::String _PG_getNormalModeString(const MaterialManager::NormalMode& NormalMode)
    {
        if (NormalMode == MaterialManager::NM_VERTEX)
        {
            return "Vertex";
        }
 
        return "Rtt";
    }
 
    ProjectedGrid::ProjectedGrid(Hydrax *h, Noise::Noise *n, const Ogre::Plane &BasePlane, const MaterialManager::NormalMode& NormalMode)
        : Module("ProjectedGrid" + _PG_getNormalModeString(NormalMode),
                 n, Mesh::Options(256, Size(0), _PG_getVertexTypeFromNormalMode(NormalMode)), NormalMode)
        , mHydrax(h)
        , mVertices(0)
        , mVerticesChoppyBuffer(0)
        , mBasePlane(BasePlane)
        , mNormal(BasePlane.normal)
        , mPos(Ogre::Vector3(0,0,0))
        , mProjectingCamera(0)
        , mTmpRndrngCamera(0)
        , mRenderingCamera(h->getCamera())
    {
    }
 
    ProjectedGrid::ProjectedGrid(Hydrax *h, Noise::Noise *n, const Ogre::Plane &BasePlane, const MaterialManager::NormalMode& NormalMode, const Options &Options)
        : Module("ProjectedGrid" + _PG_getNormalModeString(NormalMode),
                 n, Mesh::Options(Options.Complexity, Size(0), _PG_getVertexTypeFromNormalMode(NormalMode)), NormalMode)
        , mHydrax(h)
        , mVertices(0)
        , mVerticesChoppyBuffer(0)
        , mBasePlane(BasePlane)
        , mNormal(BasePlane.normal)
        , mPos(Ogre::Vector3(0,0,0))
        , mProjectingCamera(0)
        , mTmpRndrngCamera(0)
        , mRenderingCamera(h->getCamera())
    {
        setOptions(Options);
    }
 
    ProjectedGrid::~ProjectedGrid()
    {
        remove();
 
        HydraxLOG(getName() + " destroyed.");
    }
 
    void ProjectedGrid::setOptions(const Options &Options)
    {
        // Size(0) -> Infinite mesh
        mMeshOptions.MeshSize     = Size(0);
        mMeshOptions.MeshStrength = Options.Strength;
        mMeshOptions.MeshComplexity = Options.Complexity;
 
        mHydrax->getMesh()->setOptions(mMeshOptions);
        mHydrax->_setStrength(Options.Strength);
 
        // Re-create geometry if it's needed
        if (isCreated() && Options.Complexity != mOptions.Complexity)
        {
            remove();
            mOptions = Options;
            create();
 
            if (mNormalMode == MaterialManager::NM_RTT)
            {
                if (!mNoise->createGPUNormalMapResources(mHydrax->getGPUNormalMapManager()))
                {
                    HydraxLOG(mNoise->getName() + " doesn't support GPU Normal map generation.");
                }
            }
 
            Ogre::String MaterialNameTmp = mHydrax->getMesh()->getMaterialName();
            mHydrax->getMesh()->remove();
            mHydrax->getMesh()->setOptions(getMeshOptions());
            mHydrax->getMesh()->setMaterialName(MaterialNameTmp);
            mHydrax->getMesh()->create();
 
            // Force to recalculate the geometry on next frame
            mLastPosition = Ogre::Vector3(0,0,0);
            mLastOrientation = Ogre::Quaternion();
 
            return;
        }
 
        mOptions = Options;
    }
 
    void ProjectedGrid::create()
    {
        HydraxLOG("Creating " + getName() + " module.");
 
        Module::create();
 
        if (getNormalMode() == MaterialManager::NM_VERTEX)
        {
            mVertices = new Mesh::POS_NORM_VERTEX[mOptions.Complexity*mOptions.Complexity];
 
            Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
            for (int i = 0; i < mOptions.Complexity*mOptions.Complexity; i++)
            {
                Vertices[i].nx = 0;
                Vertices[i].ny = -1;
                Vertices[i].nz = 0;
            }
 
            mVerticesChoppyBuffer = new Mesh::POS_NORM_VERTEX[mOptions.Complexity*mOptions.Complexity];
        }
        else if(getNormalMode() == MaterialManager::NM_RTT)
        {
            mVertices = new Mesh::POS_VERTEX[mOptions.Complexity*mOptions.Complexity];
        }
 
        _setDisplacementAmplitude(0.0f);
 
        mTmpRndrngCamera  = new Ogre::Camera("PG_TmpRndrngCamera", NULL);
        mProjectingCamera = new Ogre::Camera("PG_ProjectingCamera", NULL);
 
        HydraxLOG(getName() + " created.");
    }
 
    void ProjectedGrid::remove()
    {
        if (!isCreated())
        {
            return;
        }
 
        Module::remove();
 
        if (mVertices)
        {
            if (getNormalMode() == MaterialManager::NM_VERTEX)
            {
                delete [] static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
                mVertices = 0;
            }
            else if (getNormalMode() == MaterialManager::NM_RTT)
            {
                delete [] static_cast<Mesh::POS_VERTEX*>(mVertices);
                mVertices = 0;
            }
        }
 
        if (mVerticesChoppyBuffer)
        {
            delete [] mVerticesChoppyBuffer;
        }
 
        if (mTmpRndrngCamera)
        {
            delete mTmpRndrngCamera;
            delete mProjectingCamera;
        }
 
        mLastPosition = Ogre::Vector3(0,0,0);
        mLastOrientation = Ogre::Quaternion();
    }
 
    void ProjectedGrid::saveCfg(Ogre::String &Data)
    {
        Module::saveCfg(Data);
 
        Data += CfgFileManager::_getCfgString("PG_ChoopyStrength", mOptions.ChoppyStrength);
        Data += CfgFileManager::_getCfgString("PG_ChoppyWaves", mOptions.ChoppyWaves);
        Data += CfgFileManager::_getCfgString("PG_Complexity", mOptions.Complexity);
        Data += CfgFileManager::_getCfgString("PG_Elevation", mOptions.Elevation);
        Data += CfgFileManager::_getCfgString("PG_ForceRecalculateGeometry", mOptions.ForceRecalculateGeometry);
        Data += CfgFileManager::_getCfgString("PG_Smooth", mOptions.Smooth);
        Data += CfgFileManager::_getCfgString("PG_Strength", mOptions.Strength); Data += "\n";
    }
 
    bool ProjectedGrid::loadCfg(Ogre::ConfigFile &CfgFile)
    {
        if (!Module::loadCfg(CfgFile))
        {
            return false;
        }
 
        HydraxLOG("\tReading options...");
        setOptions(
            Options(CfgFileManager::_getIntValue(CfgFile,   "PG_Complexity"),
                    CfgFileManager::_getFloatValue(CfgFile, "PG_Strength"),
                    CfgFileManager::_getFloatValue(CfgFile, "PG_Elevation"),
                    CfgFileManager::_getBoolValue(CfgFile,  "PG_Smooth"),
                    CfgFileManager::_getBoolValue(CfgFile,  "PG_ForceRecalculateGeometry"),
                    CfgFileManager::_getBoolValue(CfgFile,  "PG_ChoppyWaves"),
                    CfgFileManager::_getFloatValue(CfgFile, "PG_ChoopyStrength")));
 
        HydraxLOG("\tOptions readed.");
 
        return true;
    }
 
    void ProjectedGrid::update(const Ogre::Real &timeSinceLastFrame)
    {
        if (!isCreated())
        {
            return;
        }
 
        Module::update(timeSinceLastFrame);
 
        Ogre::Vector3 RenderingCameraPos = mRenderingCamera->getDerivedPosition();
 
        if (mLastPosition    != RenderingCameraPos    ||
            mLastOrientation != mRenderingCamera->getDerivedOrientation() ||
            mOptions.ForceRecalculateGeometry)
        {
            if (mLastPosition != RenderingCameraPos)
            {
                Ogre::Vector3 HydraxPos = Ogre::Vector3(RenderingCameraPos.x,mHydrax->getPosition().y,RenderingCameraPos.z);
 
                mHydrax->getMesh()->getSceneNode()->setPosition(HydraxPos);
                mHydrax->getRttManager()->getPlanesSceneNode()->setPosition(HydraxPos);
 
                // For world-space -> object-space conversion
                mHydrax->setSunPosition(mHydrax->getSunPosition());
            }
 
            float RenderingFarClipDistance = mRenderingCamera->getFarClipDistance();
 
            if (RenderingFarClipDistance > _def_MaxFarClipDistance)
            {
                mRenderingCamera->setFarClipDistance(_def_MaxFarClipDistance);
            }
 
            mLastMinMax = _getMinMax(&mRange);
 
            if (mLastMinMax)
            {
                _renderGeometry(mRange, mProjectingCamera->getViewMatrix(), RenderingCameraPos);
 
                mHydrax->getMesh()->updateGeometry(mOptions.Complexity*mOptions.Complexity, mVertices);
            }
 
            mRenderingCamera->setFarClipDistance(RenderingFarClipDistance);
        }
        else if (mLastMinMax)
        {
            if (getNormalMode() == MaterialManager::NM_VERTEX)
            {
                Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
                if (mOptions.ChoppyWaves)
                {
                    for(int i = 0; i < mOptions.Complexity*mOptions.Complexity; i++)
                    {
                        Vertices[i] = mVerticesChoppyBuffer[i];
                        Vertices[i].y = -mBasePlane.d + mNoise->getValue(RenderingCameraPos.x + Vertices[i].x, RenderingCameraPos.z + Vertices[i].z)*mOptions.Strength;
                    }
                }
                else
                {
                    for(int i = 0; i < mOptions.Complexity*mOptions.Complexity; i++)
                    {
                        Vertices[i].y = -mBasePlane.d + mNoise->getValue(RenderingCameraPos.x + Vertices[i].x, RenderingCameraPos.z + Vertices[i].z)*mOptions.Strength;
                    }
                }
            }
            else if (getNormalMode() == MaterialManager::NM_RTT)
            {
                Mesh::POS_VERTEX* Vertices = static_cast<Mesh::POS_VERTEX*>(mVertices);
 
                for(int i = 0; i < mOptions.Complexity*mOptions.Complexity; i++)
                {
                    Vertices[i].y = -mBasePlane.d + mNoise->getValue(RenderingCameraPos.x + Vertices[i].x, RenderingCameraPos.z + Vertices[i].z)*mOptions.Strength;
                }
            }
 
            // Smooth the heightdata
            if (mOptions.Smooth)
            {
                if (getNormalMode() == MaterialManager::NM_VERTEX)
                {
                    Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
                    for(int v=1; v<(mOptions.Complexity-1); v++)
                    {
                        for(int u=1; u<(mOptions.Complexity-1); u++)
                        {
                            Vertices[v*mOptions.Complexity + u].y =
                                 0.2f *
                                (Vertices[v    *mOptions.Complexity + u    ].y +
                                 Vertices[v    *mOptions.Complexity + (u+1)].y +
                                 Vertices[v    *mOptions.Complexity + (u-1)].y +
                                 Vertices[(v+1)*mOptions.Complexity + u    ].y +
                                 Vertices[(v-1)*mOptions.Complexity + u    ].y);
                        }
                    }
                }
                else if(getNormalMode() == MaterialManager::NM_RTT)
                {
                    Mesh::POS_VERTEX* Vertices = static_cast<Mesh::POS_VERTEX*>(mVertices);
 
                    for(int v=1; v<(mOptions.Complexity-1); v++)
                    {
                        for(int u=1; u<(mOptions.Complexity-1); u++)
                        {
                            Vertices[v*mOptions.Complexity + u].y =
                                 0.2f *
                                (Vertices[v    *mOptions.Complexity + u    ].y +
                                 Vertices[v    *mOptions.Complexity + (u+1)].y +
                                 Vertices[v    *mOptions.Complexity + (u-1)].y +
                                 Vertices[(v+1)*mOptions.Complexity + u    ].y +
                                 Vertices[(v-1)*mOptions.Complexity + u    ].y);
                        }
                    }
                }
            }
 
            _calculeNormals();
 
            _performChoppyWaves();
 
            mHydrax->getMesh()->updateGeometry(mOptions.Complexity*mOptions.Complexity, mVertices);
        }
 
        mLastPosition = RenderingCameraPos;
        mLastOrientation = mRenderingCamera->getDerivedOrientation();
    }
 
    bool ProjectedGrid::_renderGeometry(const Ogre::Matrix4& m,const Ogre::Matrix4& _viewMat, const Ogre::Vector3& WorldPos)
    {
        t_corners0 = _calculeWorldPosition(Ogre::Vector2( 0.0f, 0.0f),m,_viewMat);
        t_corners1 = _calculeWorldPosition(Ogre::Vector2(+1.0f, 0.0f),m,_viewMat);
        t_corners2 = _calculeWorldPosition(Ogre::Vector2( 0.0f,+1.0f),m,_viewMat);
        t_corners3 = _calculeWorldPosition(Ogre::Vector2(+1.0f,+1.0f),m,_viewMat);
 
        float du  = 1.0f/(mOptions.Complexity-1),
              dv  = 1.0f/(mOptions.Complexity-1),
              u,v = 0.0f,
              // _1_u = (1.0f-u)
              _1_u, _1_v = 1.0f,
              divide;
 
        Ogre::Vector4 result;
 
        int i = 0, iv, iu;
 
        if (getNormalMode() == MaterialManager::NM_VERTEX)
        {
            Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
            for(iv=0; iv<mOptions.Complexity; iv++)
            {
                u = 0.0f;
                _1_u = 1.0f;
                for(iu=0; iu<mOptions.Complexity; iu++)
                {
                    result.x = _1_v*(_1_u*t_corners0.x + u*t_corners1.x) + v*(_1_u*t_corners2.x + u*t_corners3.x);
                    result.z = _1_v*(_1_u*t_corners0.z + u*t_corners1.z) + v*(_1_u*t_corners2.z + u*t_corners3.z);
                    result.w = _1_v*(_1_u*t_corners0.w + u*t_corners1.w) + v*(_1_u*t_corners2.w + u*t_corners3.w);
 
                    divide = 1.0f/result.w;
                    result.x *= divide;
                    result.z *= divide;
 
                    Vertices[i].x = result.x;
                    Vertices[i].z = result.z;
                    Vertices[i].y = -mBasePlane.d + mNoise->getValue(WorldPos.x + result.x, WorldPos.z + result.z)*mOptions.Strength;
 
                    i++;
                    u += du;
                    _1_u = 1.0f-u;
                }
                v += dv;
                _1_v = 1.0f-v;
            }
 
            if (mOptions.ChoppyWaves)
            {
                for(int i = 0; i < mOptions.Complexity*mOptions.Complexity; i++)
                {
                    mVerticesChoppyBuffer[i] = Vertices[i];
                }
            }
        }
        else if(getNormalMode() == MaterialManager::NM_RTT)
        {
            Mesh::POS_VERTEX* Vertices = static_cast<Mesh::POS_VERTEX*>(mVertices);
 
            for(iv=0; iv<mOptions.Complexity; iv++)
            {
                u = 0.0f;
                _1_u = 1.0f;
                for(iu=0; iu<mOptions.Complexity; iu++)
                {
                    result.x = _1_v*(_1_u*t_corners0.x + u*t_corners1.x) + v*(_1_u*t_corners2.x + u*t_corners3.x);
                    result.z = _1_v*(_1_u*t_corners0.z + u*t_corners1.z) + v*(_1_u*t_corners2.z + u*t_corners3.z);
                    result.w = _1_v*(_1_u*t_corners0.w + u*t_corners1.w) + v*(_1_u*t_corners2.w + u*t_corners3.w);
 
                    divide = 1.0f/result.w;
                    result.x *= divide;
                    result.z *= divide;
 
                    Vertices[i].x = result.x;
                    Vertices[i].z = result.z;
                    Vertices[i].y = -mBasePlane.d + mNoise->getValue(WorldPos.x + result.x, WorldPos.z + result.z)*mOptions.Strength;
 
                    i++;
                    u += du;
                    _1_u = 1.0f-u;
                }
                v += dv;
                _1_v = 1.0f-v;
            }
        }
 
        // Smooth the heightdata
        if (mOptions.Smooth)
        {
            if (getNormalMode() == MaterialManager::NM_VERTEX)
            {
                Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
                for(iv=1; iv<(mOptions.Complexity-1); iv++)
                {
                    for(iu=1; iu<(mOptions.Complexity-1); iu++)
                    {
                        Vertices[iv*mOptions.Complexity + iu].y =
                             0.2f *
                            (Vertices[iv    *mOptions.Complexity + iu    ].y +
                             Vertices[iv    *mOptions.Complexity + (iu+1)].y +
                             Vertices[iv    *mOptions.Complexity + (iu-1)].y +
                             Vertices[(iv+1)*mOptions.Complexity + iu    ].y +
                             Vertices[(iv-1)*mOptions.Complexity + iu    ].y);
                    }
                }
            }
            else if(getNormalMode() == MaterialManager::NM_RTT)
            {
                Mesh::POS_VERTEX* Vertices = static_cast<Mesh::POS_VERTEX*>(mVertices);
 
                for(iv=1; iv<(mOptions.Complexity-1); iv++)
                {
                    for(iu=1; iu<(mOptions.Complexity-1); iu++)
                    {
                        Vertices[iv*mOptions.Complexity + iu].y =
                             0.2f *
                            (Vertices[iv    *mOptions.Complexity + iu    ].y +
                             Vertices[iv    *mOptions.Complexity + (iu+1)].y +
                             Vertices[iv    *mOptions.Complexity + (iu-1)].y +
                             Vertices[(iv+1)*mOptions.Complexity + iu    ].y +
                             Vertices[(iv-1)*mOptions.Complexity + iu    ].y);
                    }
                }
            }
        }
 
        _calculeNormals();
 
        _performChoppyWaves();
 
        return true;
    }
 
    void ProjectedGrid::_calculeNormals()
    {
        if (getNormalMode() != MaterialManager::NM_VERTEX)
        {
            return;
        }
 
        int v, u;
        Ogre::Vector3 vec1, vec2, normal;
 
        Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
        for(v=1; v<(mOptions.Complexity-1); v++)
        {
            for(u=1; u<(mOptions.Complexity-1); u++)
            {
                vec1 = Ogre::Vector3(
                    Vertices[v*mOptions.Complexity + u + 1].x-Vertices[v*mOptions.Complexity + u - 1].x,
                    Vertices[v*mOptions.Complexity + u + 1].y-Vertices[v*mOptions.Complexity + u - 1].y,
                    Vertices[v*mOptions.Complexity + u + 1].z-Vertices[v*mOptions.Complexity + u - 1].z);
 
                vec2 = Ogre::Vector3(
                    Vertices[(v+1)*mOptions.Complexity + u].x - Vertices[(v-1)*mOptions.Complexity + u].x,
                    Vertices[(v+1)*mOptions.Complexity + u].y - Vertices[(v-1)*mOptions.Complexity + u].y,
                    Vertices[(v+1)*mOptions.Complexity + u].z - Vertices[(v-1)*mOptions.Complexity + u].z);
 
                normal = vec2.crossProduct(vec1);
 
                Vertices[v*mOptions.Complexity + u].nx = normal.x;
                Vertices[v*mOptions.Complexity + u].ny = normal.y;
                Vertices[v*mOptions.Complexity + u].nz = normal.z;
            }
        }
    }
 
    void ProjectedGrid::_performChoppyWaves()
    {
        if (getNormalMode() != MaterialManager::NM_VERTEX || !mOptions.ChoppyWaves)
        {
            return;
        }
 
        int v, u,
            Underwater = 1;
 
        if (mHydrax->_isCurrentFrameUnderwater())
        {
            Underwater = -1;
        }
 
        float Dis1,  Dis2;//,
           // Dis1_, Dis2_;
 
        Ogre::Vector3 CameraDir, Norm;
        Ogre::Vector2 Dir, Perp, Norm2;
 
        CameraDir = mRenderingCamera->getDerivedDirection();
        Dir       = Ogre::Vector2(CameraDir.x, CameraDir.z).normalisedCopy();
        Perp      = Dir.perpendicular();
 
        if (Dir.x < 0 ) Dir.x = -Dir.x;
        if (Dir.y < 0 ) Dir.y = -Dir.y;
 
        if (Perp.x < 0 ) Perp.x = -Perp.x;
        if (Perp.y < 0 ) Perp.y = -Perp.y;
 
        Mesh::POS_NORM_VERTEX* Vertices = static_cast<Mesh::POS_NORM_VERTEX*>(mVertices);
 
        for(v=1; v<(mOptions.Complexity-1); v++)
        {
            Dis1 =  (Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + 1].x,
                                   mVerticesChoppyBuffer[v*mOptions.Complexity + 1].z) -
                     Ogre::Vector2(mVerticesChoppyBuffer[(v+1)*mOptions.Complexity + 1].x,
                                   mVerticesChoppyBuffer[(v+1)*mOptions.Complexity + 1].z)).length();
 
            /*Dis1_ = (Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + 1].x,
                                   mVerticesChoppyBuffer[v*mOptions.Complexity + 1].z) -
                     Ogre::Vector2(mVerticesChoppyBuffer[(v-1)*mOptions.Complexity + 1].x,
                                   mVerticesChoppyBuffer[(v-1)*mOptions.Complexity + 1].z)).length();
 
            Dis1 = (Dis1+Dis1_)/2;*/
 
            for(u=1; u<(mOptions.Complexity-1); u++)
            {
                Dis2 = (Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + u].x,
                                      mVerticesChoppyBuffer[v*mOptions.Complexity + u].z) -
                        Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + u+1].x,
                                      mVerticesChoppyBuffer[v*mOptions.Complexity + u+1].z)).length();
/*
                Dis2_ = (Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + u].x,
                                       mVerticesChoppyBuffer[v*mOptions.Complexity + u].z) -
                         Ogre::Vector2(mVerticesChoppyBuffer[v*mOptions.Complexity + u-1].x,
                                       mVerticesChoppyBuffer[v*mOptions.Complexity + u-1].z)).length();
 
                Dis2 = (Dis2+Dis2_)/2;*/
 
                Norm = Ogre::Vector3(Vertices[v*mOptions.Complexity + u].nx,
                                     Vertices[v*mOptions.Complexity + u].ny,
                                     Vertices[v*mOptions.Complexity + u].nz).
                                     normalisedCopy();
 
                Norm2 = Ogre::Vector2(Norm.x, Norm.z)  *
                                     ( (Dir  * Dis1)   +
                                       (Perp * Dis2))  *
                                      mOptions.ChoppyStrength;
 
                Vertices[v*mOptions.Complexity + u].x = mVerticesChoppyBuffer[v*mOptions.Complexity + u].x + Norm2.x * Underwater;
                Vertices[v*mOptions.Complexity + u].z = mVerticesChoppyBuffer[v*mOptions.Complexity + u].z + Norm2.y * Underwater;
            }
        }
    }
 
    // Check the point of intersection with the plane (0,1,0,0) and return the position in homogenous coordinates
    Ogre::Vector4 ProjectedGrid::_calculeWorldPosition(const Ogre::Vector2 &uv, const Ogre::Matrix4& m, const Ogre::Matrix4& _viewMat)
    {
        Ogre::Vector4 origin(uv.x,uv.y,-1,1);
        Ogre::Vector4 direction(uv.x,uv.y,1,1);
 
        origin = m*origin;
        direction = m*direction;
 
        Ogre::Vector3 _org(origin.x/origin.w,origin.y/origin.w,origin.z/origin.w);
        Ogre::Vector3 _dir(direction.x/direction.w,direction.y/direction.w,direction.z/direction.w);
        _dir -= _org;
        _dir.normalise();
 
        Ogre::Ray _ray(_org,_dir);
        std::pair<bool,Ogre::Real> _result = _ray.intersects(mBasePlane);
        float l = _result.second;
        Ogre::Vector3 worldPos = _org + _dir*l;
        Ogre::Vector4 _tempVec = _viewMat*Ogre::Vector4(worldPos);
        float _temp = -_tempVec.z/_tempVec.w;
        Ogre::Vector4 retPos(worldPos);
        retPos /= _temp;
 
        return retPos;
    }
 
    bool ProjectedGrid::_getMinMax(Ogre::Matrix4 *range)
    {
        _setDisplacementAmplitude(mOptions.Strength);
 
        float x_min,y_min,x_max,y_max;
        Ogre::Vector3 frustum[8],proj_points[24];
 
        int i,
            n_points = 0,
            src, dst;
 
        int cube[] =
           {0,1,    0,2,    2,3,    1,3,
            0,4,    2,6,    3,7,    1,5,
            4,6,    4,5,    5,7,    6,7};
 
        Ogre::Vector3 _testLine;
        Ogre::Real _dist;
        Ogre::Ray _ray;
 
        std::pair<bool,Ogre::Real> _result;
 
        // Set temporal rendering camera parameters
        mTmpRndrngCamera->setFrustumOffset(mRenderingCamera->getFrustumOffset());
        mTmpRndrngCamera->setAspectRatio(mRenderingCamera->getAspectRatio());
        mTmpRndrngCamera->setDirection(mRenderingCamera->getDerivedDirection());
        mTmpRndrngCamera->setFarClipDistance(mRenderingCamera->getFarClipDistance());
        mTmpRndrngCamera->setFOVy(mRenderingCamera->getFOVy());
        mTmpRndrngCamera->setNearClipDistance(mRenderingCamera->getNearClipDistance());
        mTmpRndrngCamera->setOrientation(mRenderingCamera->getDerivedOrientation());
        mTmpRndrngCamera->setPosition(0, mRenderingCamera->getDerivedPosition().y - mHydrax->getPosition().y, 0);
 
        Ogre::Matrix4 invviewproj = (mTmpRndrngCamera->getProjectionMatrixWithRSDepth()*mTmpRndrngCamera->getViewMatrix()).inverse();
        frustum[0] = invviewproj * Ogre::Vector3(-1,-1,0);
        frustum[1] = invviewproj * Ogre::Vector3(+1,-1,0);
        frustum[2] = invviewproj * Ogre::Vector3(-1,+1,0);
        frustum[3] = invviewproj * Ogre::Vector3(+1,+1,0);
        frustum[4] = invviewproj * Ogre::Vector3(-1,-1,+1);
        frustum[5] = invviewproj * Ogre::Vector3(+1,-1,+1);
        frustum[6] = invviewproj * Ogre::Vector3(-1,+1,+1);
        frustum[7] = invviewproj * Ogre::Vector3(+1,+1,+1);
 
        // Check intersections with upper_bound and lower_bound
        for(i=0; i<12; i++)
        {
            src=cube[i*2]; dst=cube[i*2+1];
            _testLine = frustum[dst]-frustum[src];
            _dist = _testLine.normalise();
            _ray = Ogre::Ray(frustum[src], _testLine);
            _result = Ogre::Math::intersects(_ray,mUpperBoundPlane);
            if ((_result.first) && (_result.second<_dist+0.00001))
            {
                proj_points[n_points++] = frustum[src] + _result.second * _testLine;
            }
            _result = Ogre::Math::intersects(_ray,mLowerBoundPlane);
            if ((_result.first) && (_result.second<_dist+0.00001))
            {
                proj_points[n_points++] = frustum[src] + _result.second * _testLine;
            }
        }
 
        // Check if any of the frustums vertices lie between the upper_bound and lower_bound planes
        for(i=0; i<8; i++)
        {
            if(mUpperBoundPlane.getDistance(frustum[i])/mLowerBoundPlane.getDistance(frustum[i]) < 0)
            {
                proj_points[n_points++] = frustum[i];
            }
        }
 
        // Set projecting camera parameters
        mProjectingCamera->setFrustumOffset(mTmpRndrngCamera->getFrustumOffset());
        mProjectingCamera->setAspectRatio(mTmpRndrngCamera->getAspectRatio());
        mProjectingCamera->setDirection(mTmpRndrngCamera->getDerivedDirection());
        mProjectingCamera->setFarClipDistance(mTmpRndrngCamera->getFarClipDistance());
        mProjectingCamera->setFOVy(mTmpRndrngCamera->getFOVy());
        mProjectingCamera->setNearClipDistance(mTmpRndrngCamera->getNearClipDistance());
        mProjectingCamera->setOrientation(mTmpRndrngCamera->getDerivedOrientation());
        mProjectingCamera->setPosition(mTmpRndrngCamera->getDerivedPosition());
 
        // Make sure the camera isn't too close to the plane
        float height_in_plane = mBasePlane.getDistance(mProjectingCamera->getRealPosition());
 
        bool keep_it_simple = false,
             underwater     = false;
 
        if (height_in_plane < 0.0f)
        {
            underwater = true;
        }
 
        if (keep_it_simple)
        {
            mProjectingCamera->setDirection(mTmpRndrngCamera->getDerivedDirection());
        }
        else
        {
            Ogre::Vector3 aimpoint, aimpoint2;
 
            if (height_in_plane < (mOptions.Strength + mOptions.Elevation))
            {
                if (underwater)
                {
                    mProjectingCamera->setPosition(mProjectingCamera->getRealPosition()+mLowerBoundPlane.normal*(mOptions.Strength + mOptions.Elevation - 2*height_in_plane));
                }
                else
                {
                    mProjectingCamera->setPosition(mProjectingCamera->getRealPosition()+mLowerBoundPlane.normal*(mOptions.Strength + mOptions.Elevation - height_in_plane));
                }
            }
 
            // Aim the projector at the point where the camera view-vector intersects the plane
            // if the camera is aimed away from the plane, mirror it's view-vector against the plane
            if (((mBasePlane.normal).dotProduct(mTmpRndrngCamera->getDerivedDirection()) < 0.0f) || ((mBasePlane.normal).dotProduct(mTmpRndrngCamera->getDerivedPosition()) < 0.0f ) )
            {
                _ray = Ogre::Ray(mTmpRndrngCamera->getDerivedPosition(), mTmpRndrngCamera->getDerivedDirection());
                _result = Ogre::Math::intersects(_ray,mBasePlane);
 
                if(!_result.first)
                {
                    _result.second = -_result.second;
                }
 
                aimpoint = mTmpRndrngCamera->getDerivedPosition() + _result.second * mTmpRndrngCamera->getDerivedDirection();
            }
            else
            {
                Ogre::Vector3 flipped = mTmpRndrngCamera->getDerivedDirection() - 2*mNormal* (mTmpRndrngCamera->getDerivedDirection()).dotProduct(mNormal);
                flipped.normalise();
                _ray = Ogre::Ray( mTmpRndrngCamera->getDerivedPosition(), flipped);
                _result = Ogre::Math::intersects(_ray,mBasePlane);
 
                aimpoint = mTmpRndrngCamera->getDerivedPosition() + _result.second * flipped;
            }
 
            // Force the point the camera is looking at in a plane, and have the projector look at it
            // works well against horizon, even when camera is looking upwards
            // doesn't work straight down/up
            float af = fabs((mBasePlane.normal).dotProduct(mTmpRndrngCamera->getDerivedDirection()));
            aimpoint2 = mTmpRndrngCamera->getDerivedPosition() + 10.0*mTmpRndrngCamera->getDerivedDirection();
            aimpoint2 = aimpoint2 - mNormal* (aimpoint2.dotProduct(mNormal));
 
            // Fade between aimpoint & aimpoint2 depending on view angle
            aimpoint = aimpoint*af + aimpoint2*(1.0f-af);
 
            mProjectingCamera->setDirection(aimpoint-mProjectingCamera->getRealPosition());
        }
 
        for(i=0; i<n_points; i++)
        {
            // Project the point onto the surface plane
            proj_points[i] = proj_points[i] - mBasePlane.normal*mBasePlane.getDistance(proj_points[i]);
            proj_points[i] = mProjectingCamera->getViewMatrix() * proj_points[i];
            proj_points[i] = mProjectingCamera->getProjectionMatrixWithRSDepth() * proj_points[i];
        }
 
        // Get max/min x & y-values to determine how big the "projection window" must be
        if (n_points > 0)
        {
            x_min = proj_points[0].x;
            x_max = proj_points[0].x;
            y_min = proj_points[0].y;
            y_max = proj_points[0].y;
 
            for(i=1; i<n_points; i++)
            {
                if (proj_points[i].x > x_max) x_max = proj_points[i].x;
                if (proj_points[i].x < x_min) x_min = proj_points[i].x;
                if (proj_points[i].y > y_max) y_max = proj_points[i].y;
                if (proj_points[i].y < y_min) y_min = proj_points[i].y;
            }
 
            // Build the packing matrix that spreads the grid across the "projection window"
            Ogre::Matrix4 pack(x_max-x_min, 0,              0,      x_min,
                               0,           y_max-y_min,    0,      y_min,
                               0,           0,              1,      0,
                               0,           0,              0,      1);
 
            Ogre::Matrix4 invviewproj = (mProjectingCamera->getProjectionMatrixWithRSDepth()*mProjectingCamera->getViewMatrix()).inverse();
            *range = invviewproj * pack;
 
            return true;
        }
 
        return false;
    }
 
    void ProjectedGrid::_setDisplacementAmplitude(const float &Amplitude)
    {
        mUpperBoundPlane = Ogre::Plane( mNormal, mPos + Amplitude * mNormal);
        mLowerBoundPlane = Ogre::Plane( mNormal, mPos - Amplitude * mNormal);
    }
 
    float ProjectedGrid::getHeigth(const Ogre::Vector2 &Position)
    {
        return mHydrax->getPosition().y + mNoise->getValue(Position.x, Position.y)*mOptions.Strength;
    }
}}