#ifndef _PROJECTIONMATRIX_H_
#define _PROJECTIONMATRIX_H_

#include <QtXml>
#pragma warning(disable: 4003)
#include "gmtl/gmtl.h"

namespace projection
{

/**
 * Projection matrix class.
 */
class ProjectionMatrix
{
public:

    /**
     * Constructor.
     *
     * Default projection matrix value is : FOV=30.0, 
     * AspectRatio=4/3, Near=0.1, Far=100.0
     */
    ProjectionMatrix();

    /**
     * Destructor.
     */
    virtual ~ProjectionMatrix();

    /**
     * Copy constructor.
     *
     * @param matrix Copy source matrix.
     */
    ProjectionMatrix(const ProjectionMatrix &matrix);

    /**
     * Set Field of View.
     *
     * @param fov Field of View.
     */
    void setFOV(float fov) { m_fov = fov; }

    /**
     * Retrieve Field of View.
     *
     * @return Field of View.
     */
    float getFOV() const { return m_fov; }

    /**
     * Set aspect ratio.
     *
     * @param ratio Aspect ratio.
     */
    void setAspectRatio(float ratio) { m_aspectRatio = ratio; }

    /**
     * Retrieve aspect ratio.
     *
     * @return Aspect ratio.
     */
    float getAspectRatio() const { return m_aspectRatio; }

    /**
     * Set near clip distance.
     *
     * @param Near clip distance.
     */
    void setNear(float nearDist) { m_near = nearDist; }

    /**
     * Retrieve near clip distance.
     *
     * @return Near clip distance.
     */
    float getNear() const { return m_near; }

    /**
     * Set far clip plane distance.
     *
     * @param Far clip plane distance.
     */
    void setFar(float farDist) { m_far = farDist; }

    /**
     * Retrieve far clip plane distance.
     *
     * @return Far clip plane distance.
     */
    float getFar() const { return m_far; }

    /**
     * Set vertical off-axis  distane on the Z=1.0 plane.
     *
     * @param Vertical off-axis  distane.
     */
    void setOffaxisX(float offaxisX) { m_offaxisX = offaxisX; }

    /**
     * Retrieve horizontal off-axis  distane on the Z=1.0 plane.
     *
     * @return Horizontal off-axis  distane.
     */
    float getOffaxisX() const { return m_offaxisX; }

    /**
     * Set horizontal off-axis  distane on the Z=1.0 plane.
     *
     * @param Horizontal off-axis  distane.
     */
    void setOffaxisY(float offaxisY) { m_offaxisY = offaxisY; }

    /**
     * Retrieve vertical off-axis  distane on the Z=1.0 plane.
     *
     * @return Vertical off-axis  distane.
     */
    float getOffaxisY() const { return m_offaxisY; }

    /**
     * Retrieve matrix values for glMultMatrixd().
     *
     * @return Matrix values.
     */
    float* getMatrix();

    /**
     * Retrieve four corner vectors.
     *
     * @param Four corner vectors.
     */
    void getCorners(gmtl::Vec3f vecs[4]) const;

    /**
     * Retrieve frustum parameters as 'Frustum left right bottom top near far;'.
     *
     * @param numSpaces Number of space characters for indent.
     * @return Frustum params.
     */
    QString getParams(int numSpaces=0) const;

    /**
     * Assignment operator.
     *
     * @param m Assignment source projection matrix.
     */
    ProjectionMatrix& operator=(const ProjectionMatrix& m)
    {
        if (this != &m)
        {
            m_fov = m.m_fov;
            m_aspectRatio = m.m_aspectRatio;
            m_near = m.m_near;
            m_far = m.m_far;
            m_offaxisX = m.m_offaxisX;
            m_offaxisY = m.m_offaxisY;
        }
        return *this;
    }

    /**
     * Equal operator.
     *
     * @param a Operand projection matrix.
     * @param b Operand projection matrix.
     */
    friend bool operator==(const ProjectionMatrix &a, const ProjectionMatrix &b)
    {
        return (a.m_fov == b.m_fov && a.m_aspectRatio == b.m_aspectRatio &&
                a.m_near == b.m_near && a.m_far == b.m_far &&
                a.m_offaxisX == b.m_offaxisX && a.m_offaxisY == b.m_offaxisY);
    }

    /**
     * Not equal operator.
     *
     * @param a Operand projection matrix.
     * @param b Operand projection matrix.
     */
    friend bool operator!=(const ProjectionMatrix &a, const ProjectionMatrix &b)
    {
        return !(a==b);
    }

    /**
     * Restore the projection matrix from XML data.
     *
     * @param element Parent XML element of the projection matrix data.
     */
	virtual void initFromDOMElement(const QDomElement& element);

    /**
     * Store the current projection matrix as XML data.
     *
     * @param name XML node name of the data.
     * @param doc XML document to store the data.
     * @return Current projection matrix data as XML data.
     */
    virtual QDomElement domElement(const QString& name, QDomDocument& doc) const;

private:

    float m_fov;            //!< Field of View (FOV).
    float m_aspectRatio;    //!< Aspect ratio (width / height).
    float m_near;           //!< Near clip plane distance.
    float m_far;            //!< Far clip plane distance.
    float m_offaxisX;       //!< Horizontal off-axis distance.
    float m_offaxisY;       //!< Vertical off-axis distance.

    float m_mat[16];        //!< Matrix values. Calculated when getMatrix() called.
};

}; // projection

#endif // _PROJECTIONMATRIX_H_