source: downloads/ogre_src_v1-9-0/OgreMain/include/OgreShadowCameraSetupPlaneOptimal.h @ 153

/*
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This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2013 Torus Knot Software Ltd

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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.
        @remarks
            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.
                @note Important: 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 Second important 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:
                MovablePlane* mPlane;   ///< pointer to plane of interest
        private:
                PlaneOptimalShadowCameraSetup() {}      ///< Default constructor is private

                /// helper function computing projection matrix given constraints
                Matrix4 computeConstrainedProjection( const Vector4& pinhole, 
                                                                                          const vector<Vector4>::type& fpoint, 
                                                                                          const vector<Vector2>::type& constraint) const;

        public:
                /// Constructor -- requires a plane of interest
                PlaneOptimalShadowCameraSetup(MovablePlane *plane);
                /// Destructor
                virtual ~PlaneOptimalShadowCameraSetup();

                /// Returns shadow camera configured to get 1-1 homography between screen and shadow map when restricted to plane
                virtual void getShadowCamera (const SceneManager *sm, const Camera *cam, 
                                                                          const Viewport *vp, const Light *light, Camera *texCam, size_t iteration) const;
        };
        /** @} */
        /** @} */

}

#include "OgreHeaderSuffix.h"

#endif