/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library 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 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGTERRAIN_LAYER
#define OSGTERRAIN_LAYER 1

#include <osg/Image>
#include <osg/Shape>
#include <osg/Array>

#include <osgTerrain/Locator>

namespace osgTerrain {

class OSGTERRAIN_EXPORT Layer : public osg::Object
{
    public:

        Layer();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        Layer(const Layer&,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
        
        META_Object(osgTerrain, Layer);
        
        
        void setLocator(Locator* locator) { _locator = locator; }
        Locator* getLocator() { return _locator.get(); }
        const Locator* getLocator() const { return _locator.get(); }

        virtual unsigned int getNumColumns() const { return 0; }
        virtual unsigned int getNumRows() const { return 0; }

        void setDefaultValue(const osg::Vec4& value) { _defaultValue = value; }
        const osg::Vec4& getDefaultValue() const { return _defaultValue; }
        
        virtual bool transform(float offset, float scale) { return false; }

        virtual bool getValue(unsigned int /*i*/, unsigned int /*j*/, float& /*value*/) const { return false; }
        virtual bool getValue(unsigned int /*i*/, unsigned int /*j*/, osg::Vec2& /*value*/) const { return false; }
        virtual bool getValue(unsigned int /*i*/, unsigned int /*j*/, osg::Vec3& /*value*/) const { return false; }
        virtual bool getValue(unsigned int /*i*/, unsigned int /*j*/, osg::Vec4& /*value*/) const { return false; }

        inline void computeIndices(double ndc_x, double ndc_y, unsigned int& i, unsigned int& j, double& ir, double& jr)
        {
            ndc_x *= double(getNumColumns()-1);
            ndc_y *= double(getNumRows()-1);
            i = (unsigned int)(ndc_x);
            j = (unsigned int)(ndc_y);
            ir = ndc_x - double(i);
            jr = ndc_y - double(j);
        } 


        inline bool getInterpolatedValue(double ndc_x, double ndc_y, float& value)
        {
            unsigned int i,j;
            double ir, jr;
            computeIndices(ndc_x, ndc_y, i, j, ir, jr);
            value = 0.0f;
            double div = 0.0f;
            float v,r;
            
            r = (1.0f-ir)*(1.0f-jr);
            if (r>0.0 && getValue(i,j,v)) 
            {
                value += v*r;
                div += r;
            }
            
            r = (ir)*(1.0f-jr);
            if (r>0.0 && getValue(i+1,j,v)) 
            {
                value += v*r;
                div += r;
            }
            
            r = (ir)*(jr);
            if (r>0.0 && getValue(i+1,j+1,v)) 
            {
                value += v*r;
                div += r;
            }
            
            r = (1.0f-ir)*(jr);
            if (r>0.0 && getValue(i,j+1,v)) 
            {
                value += v*r;
                div += r;
            }
            
            if (div != 0.0)
            {
                value /= div;
                return true;
            }
            
            value = 0.0;
            return false;
        }

        virtual osg::BoundingSphere computeBound() const;

    protected:

        virtual ~Layer();

        osg::ref_ptr<Locator>   _locator;
        osg::Vec4               _defaultValue;

};

class OSGTERRAIN_EXPORT ImageLayer : public Layer
{
    public:

        ImageLayer();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        ImageLayer(const ImageLayer& imageLayer,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
        
        virtual bool transform(float offset, float scale);

        void setImage(osg::Image* image);
        osg::Image* getImage() { return _image.get(); }
        const osg::Image* getImage() const { return _image.get(); }

        virtual unsigned int getNumColumns() const { return _image.valid() ? _image->s() : 0; }
        virtual unsigned int getNumRows() const { return _image.valid() ? _image->t() : 0;  }

        virtual bool getValue(unsigned int i, unsigned int j, float& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec2& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec3& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec4& value) const;

    protected:

        virtual ~ImageLayer() {}

        osg::ref_ptr<osg::Image> _image;

};

class OSGTERRAIN_EXPORT HeightFieldLayer : public Layer
{
    public:

        HeightFieldLayer();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        HeightFieldLayer(const HeightFieldLayer& hfLayer,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
        
        virtual bool transform(float offset, float scale);

        void setHeightField(osg::HeightField* hf);
        osg::HeightField* getHeightField() { return _heightField.get(); }
        const osg::HeightField* getHeightField() const { return _heightField.get(); }

        virtual unsigned int getNumColumns() const { return _heightField.valid() ? _heightField->getNumColumns() : 0; }
        virtual unsigned int getNumRows() const { return _heightField.valid() ? _heightField->getNumRows() : 0;  }

        virtual bool getValue(unsigned int i, unsigned int j, float& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec2& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec3& value) const;
        virtual bool getValue(unsigned int i, unsigned int j, osg::Vec4& value) const;

    protected:

        virtual ~HeightFieldLayer() {}

        osg::ref_ptr<osg::HeightField> _heightField;

};

}

#endif