SViewFrustum.h

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// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef __S_VIEW_FRUSTUM_H_INCLUDED__
#define __S_VIEW_FRUSTUM_H_INCLUDED__

#include "plane3d.h"
#include "vector3d.h"
#include "line3d.h"
#include "aabbox3d.h"
#include "matrix4.h"
#include "IVideoDriver.h"

namespace irr
{
namespace scene
{


    struct SViewFrustum
    {
        enum VFPLANES
        {
            VF_FAR_PLANE = 0,
            VF_NEAR_PLANE,
            VF_LEFT_PLANE,
            VF_RIGHT_PLANE,
            VF_BOTTOM_PLANE,
            VF_TOP_PLANE,

            VF_PLANE_COUNT
        };


        SViewFrustum() {}

        SViewFrustum(const SViewFrustum& other);

        SViewFrustum(const core::matrix4& mat);

        inline void setFrom(const core::matrix4& mat);


        void transform(const core::matrix4& mat);

        core::vector3df getFarLeftUp() const;

        core::vector3df getFarLeftDown() const;

        core::vector3df getFarRightUp() const;

        core::vector3df getFarRightDown() const;

        core::vector3df getNearLeftUp() const;

        core::vector3df getNearLeftDown() const;

        core::vector3df getNearRightUp() const;

        core::vector3df getNearRightDown() const;

        const core::aabbox3d<f32> &getBoundingBox() const;

        inline void recalculateBoundingBox();

        core::matrix4& getTransform( video::E_TRANSFORMATION_STATE state);

        const core::matrix4& getTransform( video::E_TRANSFORMATION_STATE state) const;


        bool clipLine(core::line3d<f32>& line) const;

        core::vector3df cameraPosition;

        core::plane3d<f32> planes[VF_PLANE_COUNT];

        core::aabbox3d<f32> boundingBox;

    private:
        enum E_TRANSFORMATION_STATE_FRUSTUM
        {
            ETS_VIEW = 0,
            ETS_PROJECTION = 1,
            ETS_COUNT_FRUSTUM
        };

        core::matrix4 Matrices[ETS_COUNT_FRUSTUM];
    };


    inline SViewFrustum::SViewFrustum(const SViewFrustum& other)
    {
        cameraPosition=other.cameraPosition;
        boundingBox=other.boundingBox;

        u32 i;
        for (i=0; i<VF_PLANE_COUNT; ++i)
            planes[i]=other.planes[i];

        for (i=0; i<ETS_COUNT_FRUSTUM; ++i)
            Matrices[i]=other.Matrices[i];
    }

    inline SViewFrustum::SViewFrustum(const core::matrix4& mat)
    {
        setFrom ( mat );
    }


    inline void SViewFrustum::transform(const core::matrix4& mat)
    {
        for (u32 i=0; i<VF_PLANE_COUNT; ++i)
            mat.transformPlane(planes[i]);

        mat.transformVect(cameraPosition);
        recalculateBoundingBox();
    }


    inline core::vector3df SViewFrustum::getFarLeftUp() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_TOP_PLANE],
            planes[scene::SViewFrustum::VF_LEFT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getFarLeftDown() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
            planes[scene::SViewFrustum::VF_LEFT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getFarRightUp() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_TOP_PLANE],
            planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getFarRightDown() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_FAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
            planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getNearLeftUp() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_TOP_PLANE],
            planes[scene::SViewFrustum::VF_LEFT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getNearLeftDown() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
            planes[scene::SViewFrustum::VF_LEFT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getNearRightUp() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_TOP_PLANE],
            planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);

        return p;
    }

    inline core::vector3df SViewFrustum::getNearRightDown() const
    {
        core::vector3df p;
        planes[scene::SViewFrustum::VF_NEAR_PLANE].getIntersectionWithPlanes(
            planes[scene::SViewFrustum::VF_BOTTOM_PLANE],
            planes[scene::SViewFrustum::VF_RIGHT_PLANE], p);

        return p;
    }

    inline const core::aabbox3d<f32> &SViewFrustum::getBoundingBox() const
    {
        return boundingBox;
    }

    inline void SViewFrustum::recalculateBoundingBox()
    {
        boundingBox.reset ( cameraPosition );

        boundingBox.addInternalPoint(getFarLeftUp());
        boundingBox.addInternalPoint(getFarRightUp());
        boundingBox.addInternalPoint(getFarLeftDown());
        boundingBox.addInternalPoint(getFarRightDown());
    }

    inline void SViewFrustum::setFrom(const core::matrix4& mat)
    {
        // left clipping plane
        planes[VF_LEFT_PLANE].Normal.X = mat[3 ] + mat[0];
        planes[VF_LEFT_PLANE].Normal.Y = mat[7 ] + mat[4];
        planes[VF_LEFT_PLANE].Normal.Z = mat[11] + mat[8];
        planes[VF_LEFT_PLANE].D =        mat[15] + mat[12];

        // right clipping plane
        planes[VF_RIGHT_PLANE].Normal.X = mat[3 ] - mat[0];
        planes[VF_RIGHT_PLANE].Normal.Y = mat[7 ] - mat[4];
        planes[VF_RIGHT_PLANE].Normal.Z = mat[11] - mat[8];
        planes[VF_RIGHT_PLANE].D =        mat[15] - mat[12];

        // top clipping plane
        planes[VF_TOP_PLANE].Normal.X = mat[3 ] - mat[1];
        planes[VF_TOP_PLANE].Normal.Y = mat[7 ] - mat[5];
        planes[VF_TOP_PLANE].Normal.Z = mat[11] - mat[9];
        planes[VF_TOP_PLANE].D =        mat[15] - mat[13];

        // bottom clipping plane
        planes[VF_BOTTOM_PLANE].Normal.X = mat[3 ] + mat[1];
        planes[VF_BOTTOM_PLANE].Normal.Y = mat[7 ] + mat[5];
        planes[VF_BOTTOM_PLANE].Normal.Z = mat[11] + mat[9];
        planes[VF_BOTTOM_PLANE].D =        mat[15] + mat[13];

        // far clipping plane
        planes[VF_FAR_PLANE].Normal.X = mat[3 ] - mat[2];
        planes[VF_FAR_PLANE].Normal.Y = mat[7 ] - mat[6];
        planes[VF_FAR_PLANE].Normal.Z = mat[11] - mat[10];
        planes[VF_FAR_PLANE].D =        mat[15] - mat[14];

        // near clipping plane
        planes[VF_NEAR_PLANE].Normal.X = mat[2];
        planes[VF_NEAR_PLANE].Normal.Y = mat[6];
        planes[VF_NEAR_PLANE].Normal.Z = mat[10];
        planes[VF_NEAR_PLANE].D =        mat[14];

        // normalize normals
        u32 i;
        for ( i=0; i != VF_PLANE_COUNT; ++i)
        {
            const f32 len = -core::reciprocal_squareroot(
                    planes[i].Normal.getLengthSQ());
            planes[i].Normal *= len;
            planes[i].D *= len;
        }

        // make bounding box
        recalculateBoundingBox();
    }

    inline core::matrix4& SViewFrustum::getTransform(video::E_TRANSFORMATION_STATE state )
    {
        u32 index = 0;
        switch ( state )
        {
            case video::ETS_PROJECTION:
                index = SViewFrustum::ETS_PROJECTION; break;
            case video::ETS_VIEW:
                index = SViewFrustum::ETS_VIEW; break;
            default:
                break;
        }
        return Matrices [ index ];
    }

    inline const core::matrix4& SViewFrustum::getTransform(video::E_TRANSFORMATION_STATE state ) const
    {
        u32 index = 0;
        switch ( state )
        {
            case video::ETS_PROJECTION:
                index = SViewFrustum::ETS_PROJECTION; break;
            case video::ETS_VIEW:
                index = SViewFrustum::ETS_VIEW; break;
            default:
                break;
        }
        return Matrices [ index ];
    }

    inline bool SViewFrustum::clipLine(core::line3d<f32>& line) const
    {
        bool wasClipped = false;
        for (u32 i=0; i < VF_PLANE_COUNT; ++i)
        {
            if (planes[i].classifyPointRelation(line.start) == core::ISREL3D_FRONT)
            {
                line.start = line.start.getInterpolated(line.end,
                        planes[i].getKnownIntersectionWithLine(line.start, line.end));
                wasClipped = true;
            }
            if (planes[i].classifyPointRelation(line.end) == core::ISREL3D_FRONT)
            {
                line.end = line.start.getInterpolated(line.end,
                        planes[i].getKnownIntersectionWithLine(line.start, line.end));
                wasClipped = true;
            }
        }
        return wasClipped;
    }


} // end namespace scene
} // end namespace irr

#endif