#include <QtOpenGL>

#include "Frustum.h"

using namespace projection;
using namespace gmtl;

/**
 * Constructor.
 */
Frustum::Frustum() : QObject()
{
    m_bShow = true;
    m_bShowArea = true;
    m_visibleFar = 1.2f;
    m_color.setRgb(0, 0, 255);

    m_transformMatrix.setUseScaling(false);
}

/**
 * Destructor.
 */
Frustum::~Frustum()
{
}

/**
 * Set projection matrix of the frustum.
 *
 * @param matrix Projection matrix of the frustum.
 */
void Frustum::setProjectionMatrix(const ProjectionMatrix& matrix)
{
    m_projectionMatrix = matrix;
    emit dataChanged();
}

/**
 * Retrieve projection matrix of the frustum.
 *
 * @return Projection matrix of the frustum.
 */
ProjectionMatrix Frustum::getProjectionMatrix() const
{
    return m_projectionMatrix;
}

/**
 * Set transform matrix of the frustum.
 *
 * @param matrix Transform matrix of the frustum.
 */
void Frustum::setTransformMatrix(const TransformMatrix& matrix)
{
    m_transformMatrix = matrix;
    emit dataChanged();
}

/**
 * Retrieve transform matrix of the frustum.
 *
 * @return Transform matrix of the frustum.
 */
TransformMatrix Frustum::getTransformMatrix() const
{
    return m_transformMatrix;
}

/**
 * Set color of the frustum shape object.
 *
 * @param color Color of the frustum shape object.
 */
void Frustum::setColor(const QColor& color)
{
    m_color = color;
    emit dataChanged();
}

/**
 * Retrieve color of the frustum shape object.
 *
 * @return Color of the frustum shape object.
 */
QColor Frustum::getColor() const
{
    return m_color;
}

/**
 * Show or hide the frustum shape object.
 *
 * @param bShow True to show the frustum shape object, false to hide.
 */
void Frustum::setShow(bool bShow)
{
    m_bShow = bShow;
    emit dataChanged();
}

/**
 * Check whether the frustum shape object is shown or not.
 *
 * @return True if the frustum shape object is shown.
 */
bool Frustum::getShow() const
{
    return m_bShow;
}

/**
 * Show or hide the frustum projected area.
 *
 * @param bShow True to show the frustum projected area, false to hide.
 */
void Frustum::setShowArea(bool bShow)
{
    m_bShowArea = bShow;
    emit dataChanged();
}

/**
 * Check whether the frustum projected area is shown or not.
 *
 * @return True if the frustum projected area is shown.
 */
bool Frustum::getShowArea() const
{
    return m_bShowArea;
}

/**
 * Set far clip plane distance of the frame shape object. It doesn't modify the  data.
 *
 * @param farDist Far clip plane distance of the frame shape object.
 */
void Frustum::setVisibleFar(float farDist)
{
    m_visibleFar = farDist;
}

/**
 * Retrieve far clip plane distance of the frame shape object.
 *
 * @return Far clip plane distance of the frame shape object.
 */
float Frustum::getVisibleFar() const
{
    return m_visibleFar;
}

/**
 * Draw frustum shape object.
 *
 * @param bSelected True to draw with selection highlight.
 */
void Frustum::draw(bool bSelected)
{
    if (m_bShow)
    {
        glPushMatrix();
        glMultMatrixf(m_transformMatrix.getMatrix().getData());
        glPushAttrib(GL_ENABLE_BIT | GL_CURRENT_BIT | GL_LINE_BIT);

        if (bSelected)
            glLineWidth(3.0f);

        float left =  -tanf(Math::deg2Rad(m_projectionMatrix.getFOV()/2.0f)) * m_projectionMatrix.getAspectRatio() + m_projectionMatrix.getOffaxisX();
        float right =  tanf(Math::deg2Rad(m_projectionMatrix.getFOV()/2.0f)) * m_projectionMatrix.getAspectRatio() + m_projectionMatrix.getOffaxisX();
        float top =   -tanf(Math::deg2Rad(m_projectionMatrix.getFOV()/2.0f)) + m_projectionMatrix.getOffaxisY();
        float bottom = tanf(Math::deg2Rad(m_projectionMatrix.getFOV()/2.0f)) + m_projectionMatrix.getOffaxisY();
        float nearDist = m_projectionMatrix.getNear();
        float farDist = m_projectionMatrix.getFar();
        if (m_visibleFar < farDist)
            farDist = m_visibleFar;

        glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
        glDisable(GL_LIGHTING);

        glBegin(GL_LINE_LOOP);
        glVertex3f(nearDist*left,  nearDist*bottom, -nearDist);
        glVertex3f(nearDist*right, nearDist*bottom, -nearDist);
        glVertex3f(nearDist*right, nearDist*top,    -nearDist);
        glVertex3f(nearDist*left,  nearDist*top,    -nearDist);
        glEnd();
        glBegin(GL_LINE_LOOP);
        glVertex3f(farDist*left,  farDist*bottom, -farDist);
        glVertex3f(farDist*right, farDist*bottom, -farDist);
        glVertex3f(farDist*right, farDist*top,    -farDist);
        glVertex3f(farDist*left,  farDist*top,    -farDist);
        glEnd();
        glBegin(GL_LINES);
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*left,  farDist*bottom, -farDist);
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*right, farDist*bottom, -farDist);
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*right, farDist*top,    -farDist);
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*left,  farDist*top,    -farDist);
        glEnd();

        glColor4f((float)m_color.red()/255.0f, (float)m_color.green()/255.0f, (float)m_color.blue()/255.0f, 0.25f);
        glEnable(GL_LIGHTING);
        glEnable(GL_BLEND);
        glDepthMask(false);

        glBegin(GL_TRIANGLES);
        glNormal3f(0.0f, cosf(Math::deg2Rad(m_projectionMatrix.getFOV())/2.0f), -sinf(Math::deg2Rad(m_projectionMatrix.getFOV())/2.0f));
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*left,  farDist*bottom, -farDist);
        glVertex3f(farDist*right, farDist*bottom, -farDist);
        glNormal3f( cosf(Math::deg2Rad(m_projectionMatrix.getFOV())*m_projectionMatrix.getAspectRatio()/2.0f),
                    0.0f,
                   -sinf(Math::deg2Rad(m_projectionMatrix.getFOV())*m_projectionMatrix.getAspectRatio()/2.0f));
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*right, farDist*bottom, -farDist);
        glVertex3f(farDist*right, farDist*top,    -farDist);
        glNormal3f(0.0f, -cosf(Math::deg2Rad(m_projectionMatrix.getFOV())/2.0f), -sinf(Math::deg2Rad(m_projectionMatrix.getFOV())/2.0f));
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*right, farDist*top, -farDist);
        glVertex3f(farDist*left,  farDist*top, -farDist);
        glNormal3f(-cosf(Math::deg2Rad(m_projectionMatrix.getFOV())*m_projectionMatrix.getAspectRatio()/2.0f),
                    0.0f,
                   -sinf(Math::deg2Rad(m_projectionMatrix.getFOV())*m_projectionMatrix.getAspectRatio()/2.0f));
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(farDist*left, farDist*top,    -farDist);
        glVertex3f(farDist*left, farDist*bottom, -farDist);
        glEnd();

        glDepthMask(true);
        glPopAttrib();
        glPopMatrix();
    }
}

/**
 * Assignment operator.
 *
 * @param frustum Assignment source frustum.
 */
Frustum& Frustum::operator=(const Frustum& frustum)
{
    if (this != &frustum)
    {
        m_projectionMatrix = frustum.m_projectionMatrix;
        m_transformMatrix = frustum.m_transformMatrix;
        m_bShow = frustum.m_bShow;
        m_visibleFar = frustum.m_visibleFar;
        m_color = frustum.m_color;
    }
    return *this;
}

/**
 * Restore the frustum data from XML data.
 *
 * @param element Parent XML element of the frustum data.
 */
void Frustum::initFromDOMElement(const QDomElement& element)
{
    if (!element.isNull())
    {
        m_projectionMatrix.initFromDOMElement(element.firstChildElement("ProjectionMatrix"));
        m_transformMatrix.initFromDOMElement(element.firstChildElement("TransformMatrix"));
        m_bShow = element.attribute("show").toLower()=="true";
        m_bShowArea = element.attribute("showArea").toLower()=="true";
    }
}

/**
 * Store the current frustum data as XML data.
 *
 * @param name XML node name of the data.
 * @param doc XML document to store the data.
 * @return Current frustum data as XML data.
 */
QDomElement Frustum::domElement(const QString& name, QDomDocument& doc) const
{
    QDomElement de = doc.createElement(name);

    de.appendChild(m_projectionMatrix.domElement("ProjectionMatrix", doc));
    de.appendChild(m_transformMatrix.domElement("TransformMatrix", doc));
    de.setAttribute("show", (m_bShow?"true":"false"));
    de.setAttribute("showArea", (m_bShowArea?"true":"false"));

    return de;
}