VRS - The Virtual Rendering System

version 3.3

viewinfo.h

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/******************************************************************************
 * VRS - The Virtual Rendering System
 * Copyright (C) 2000-2008 Computer Graphics Systems Group at the 
 * Hasso-Plattner-Institute (HPI), Potsdam, Germany.
 *
 * This  library  is  free  software; you can redistribute it and/or  modify it
 * under the terms of the GNU Lesser General Public  License  as  published  by
 * the  Free  Software  Foundation;  either  version 2.1 of the License, or (at
 * your option) any later version. This library  is  distributed  in  the  hope
 * that  it will be useful, but  WITHOUT ANY WARRANTY; without even the implied
 * warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE.  See  the
 * GNU Lesser General Public License for more details. You should have received
 * a copy of the GNU Lesser+ General Public License along with this library; if
 * not, write to the FreeSoftware Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA, 02111-1307, USA.
 ******************************************************************************/

#ifndef VRS_VIEWINFO_H
#define VRS_VIEWINFO_H

#include <vrs/sharedobj.h>
#include <vrs/bounds.h>
#include <vrs/vector.h>

namespace VRS {

    class Engine;

    // available frames of reference: (= for a standard camera)
    // - object         (plain vertex => no transformation)
    // - world          (+ modelview - orientation matrix)
    // - camera         (+ orientation matrix)
    // - projection     (+ projection matrix)
    // - ndc            (+ post-projection transform ,e.g., large-scale snapshot)
    // - viewport       (+ viewport => pixels)


    class VRS_CORE_API ViewInfo : public VRS::SharedObj {
    public:
        ViewInfo(SO<const Engine> engine);

        ~ViewInfo();

        // basic info
        virtual int viewportWidth() const;
        virtual int viewportHeight() const;

        // camera's frame of reference in object space
        virtual const Vector &cameraPosition() const = 0;
        virtual const Vector &cameraUp() const = 0;
        virtual const Vector &cameraRight() const = 0;
        virtual const Vector &cameraDirection() const = 0;
        virtual double farPlaneDistance() const = 0;
        virtual double nearPlaneDistance() const = 0;

        // effective distance to camera (might differ from eucledian distance!)
        virtual double distanceToCamera2(const Vector &point) const = 0;
        virtual double distanceToCamera2(const Bounds &bbox) const = 0;

        // size of a sphere or segment on screen (pixels)
        virtual double pixelSize2(const Vector &center, double radius) const = 0;
        virtual double pixelSize2(const Vector &segmentBegin, const Vector &segmentEnd) const = 0;

        // culling support
        enum CullingPos { Outside = -1, InAndOut = 0, Inside = 1 };
        VRS_SERIALIZABLE_CLASS_ENUM(CullingPos);

        virtual CullingPos culling(const Vector& point, double radius) const = 0;
        virtual CullingPos culling(const Vector& point) const = 0;
        // defaults to culling(point, 0.0)
        virtual CullingPos culling(const Bounds& bbox) const = 0;

        VRS_TYPEINFO(ViewInfo, SharedObj);

    protected:
        ViewInfo();

        int viewportWidth_;
        int viewportHeight_;
    };

    class VRS_CORE_API ViewInfoFactory : public VRS::SharedObj {
    public:
        // do not reuse a single ViewInfo, since multiple ViewInfos might be in use concurrently
        virtual SO<ViewInfo> newViewInfo(SO<const Engine> engine) = 0;

        VRS_TYPEINFO(ViewInfoFactory, SharedObj);
    };

    class VRS_CORE_API ModelviewProjectionViewInfo :
        public ViewInfo
    {
    public:
        VRS_TYPEINFO(ModelviewProjectionViewInfo, ViewInfo);

        ModelviewProjectionViewInfo(
            const Matrix& modelview,
            const Matrix& projection,
            unsigned int viewportPixelsX,
            unsigned int viewportPixelsY
        );

        virtual double farPlaneDistance() const;
        virtual void setFarPlaneDistance(double farPlaneDistance) { farPlane_ = farPlaneDistance; };

        virtual double nearPlaneDistance() const;
        virtual void setNearPlaneDistance(double nearPlaneDistance) { nearPlane_ = nearPlaneDistance; };

        inline const Vector& focus(void) const { return focus_; };
        inline void setFocus(const Vector& focus) { focus_ = focus; };

        virtual const Vector &cameraPosition() const;
        inline void setCameraPosition(const Vector& cameraPosition) { position_ = cameraPosition; };

        virtual const Vector &cameraUp() const;
        inline void setCameraUp(const Vector& cameraUp) { upVector_ = cameraUp; };

        virtual const Vector &cameraRight() const;
        inline void setCameraRight(const Vector& cameraRight) { rightVector_ = cameraRight; };
        virtual const Vector &cameraDirection() const;

        virtual double distanceToCamera2(const Vector &point) const;
        virtual double distanceToCamera2(const Bounds &bbox) const;

        virtual double pixelSize2(const Vector &center, double radius) const;
        virtual double pixelSize2(const Vector &segmentBegin, const Vector &segmentEnd) const;

        virtual CullingPos culling(const Vector& point, double radius) const;
        virtual CullingPos culling(const Vector& point) const;
        virtual CullingPos culling(const Bounds& bbox) const;

        inline const Vector& leftPlane(void) const { return leftPlane_; };
        inline void setLeftPlane(const Vector& leftPlane) { leftPlane_ = leftPlane; };

        inline const Vector& rightPlane(void) const { return rightPlane_; };
        inline void setRightPlane(const Vector& rightPlane) { rightPlane_ = rightPlane; };

        inline const Vector& topPlane(void) const { return topPlane_; };
        inline void setTopPlane(const Vector& topPlane) { topPlane_ = topPlane; };

        inline const Vector& bottomPlane(void) const { return bottomPlane_; };
        inline void setBottomPlane(const Vector& bottomPlane) { bottomPlane_ = bottomPlane; };

        inline const Vector& clipNormal(void) const { return clipNormal_; };
        inline void setClipNormal(const Vector& clipNormal) { clipNormal_ = clipNormal; };

        inline const Vector& depthVector(void) const { return depthVector_; };
        inline void setDepthVector(const Vector& depthVector) { depthVector_ = depthVector; };
    
        enum PrjType { Unknown, Parallel, Perspective };
        virtual PrjType projectionType() const;

    protected:
        template<class T>
        inline CullingPos xculling(const T& obj) const;

    private:
        void decompose(const Matrix& invMat);

        Matrix mvp_;

        Vector position_;
        Vector focus_;
        Vector upVector_;
        Vector rightVector_;
        Vector depthVector_;
        Vector leftPlane_;
        Vector rightPlane_;
        Vector topPlane_;
        Vector bottomPlane_;
        Vector clipNormal_;

        double leftAngle_;
        double rightAngle_;
        double topAngle_;
        double bottomAngle_;
        double nearPlane_;
        double farPlane_;

        Vector llf_;
        Vector urb_;

        double pixelSizeVector_[4];

        PrjType type_;

    }; // class ModelviewProjectionViewInfo

} // namespace VRS

#endif // VRS_VIEWINFO_H

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