/*

-----------------------------------------------------------------------------

This source file is part of OGRE

(Object-oriented Graphics Rendering Engine)

For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

THE SOFTWARE.

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*/

#ifndef __ShadowCameraSetupPlaneOptimal_H__

#define __ShadowCameraSetupPlaneOptimal_H__

#include "OgrePrerequisites.h"

#include "OgreShadowCameraSetup.h"

#include "OgreHeaderPrefix.h"

namespace Ogre {

    /** \addtogroup Core

    *  @{

    */

    /** \addtogroup Scene

    *  @{

    */

    /** Implements the plane optimal shadow camera algorithm.

        Given a plane of interest, it is possible to set up the shadow camera

        matrix such that the mapping between screen and shadow map is the identity

        (when restricted to pixels that view the plane of interest).  Therefore,

        if the shadow map resolution matches the screen space resolution (of the

        seen planar receiver), we can get pixel perfect shadowing on the plane.

        Off the plane, the shadowing is not guaranteed to be perfect and will

        likely exhibit the usual sampling artifacts associated with shadow mapping.

        @attention this routine requires double-precision calculations. When you

            are running under Direct3D, you must ensure that you set the floating

            point mode to 'Consistent' rather than 'Fastest' to ensure this precision.

            This does allegedly come with some performance cost but when measuring 

            it appears to be negligible in modern systems for normal usage.

        @note this projection also only works for lights with

            a finite position. Therefore you cannot use it for directional lights

            at this time.

    */

    class _OgreExport PlaneOptimalShadowCameraSetup : public ShadowCameraSetup

    {

    private:

        const MovablePlane* mPlane;   ///< pointer to plane of interest

    private:

        /// helper function computing projection matrix given constraints

        Matrix4 computeConstrainedProjection( const Vector4& pinhole, 

                                              const std::vector<Vector4>& fpoint, 

                                              const std::vector<Vector2>& constraint) const;

    public:

        /// @deprecated use create()

        PlaneOptimalShadowCameraSetup(const MovablePlane *plane);

        virtual ~PlaneOptimalShadowCameraSetup();

        /// Constructor -- requires a plane of interest

        static ShadowCameraSetupPtr create(const MovablePlane *plane)

        {

            return std::make_shared<PlaneOptimalShadowCameraSetup>(plane);

        }

        /// Returns shadow camera configured to get 1-1 homography between screen and shadow map when restricted to plane

        void getShadowCamera (const SceneManager *sm, const Camera *cam,

                                      const Viewport *vp, const Light *light, Camera *texCam, size_t iteration) const override;

    };

    /** @} */

    /** @} */

}

#include "OgreHeaderSuffix.h"

#endif