TrailGroup.hpp

/*
 * Stellarium
 * Copyright (C) 2010 Fabien Chereau
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335, USA.
 */

#ifndef TRAILGROUP_HPP
#define TRAILGROUP_HPP

#include "VecMath.hpp"
#include "StelCore.hpp"
#include "StelObjectType.hpp"


class TrailGroup
{
public:
    TrailGroup(float atimeExtent);

    ~TrailGroup();

    void draw(StelCore* core, class StelRenderer* renderer);

    // Add 1 point to all the curves at current time and suppress too old points
    void update();

    // Set the matrix to use to post process J2000 positions before storing in the trail
    void setJ2000ToTrailNative(const Mat4d& m);

    void addObject(const StelObjectP&, const Vec3f* col=NULL);

    void setOpacity(float op) 
    {
        opacity = op;
    }

    void reset();

private:
    struct ColoredVertex
    {
        Vec3f position;
        Vec4f color;

        ColoredVertex(){}

        VERTEX_ATTRIBUTES(Vec3f Position, Vec4f Color);
    };

    struct Trail
    {
        Trail(const StelObjectP& obj, const Vec3f& col) 
            : stelObject(obj), color(col), vertexBuffer(NULL) 
        {
        }

        StelObjectP stelObject;

        // Using QVector instead of QList.
        // QList is an array of pointers to elements, which are 8 byte on 64-bit,
        // while Vec3f is 12 byte, so not much space saved (or time, at popFront).
        // At the same time, it has a bad cache performance that slows down drawing.

        // All previous positions
        QVector<Vec3f> posHistory;
        Vec3f color;
        StelVertexBuffer<ColoredVertex>* vertexBuffer;
    };

    QList<Trail> allTrails;

    // Maximum time extent in days
    float timeExtent;

    QList<float> times;

    Mat4d j2000ToTrailNative;
    Mat4d j2000ToTrailNativeInverted;

    float opacity;

    double lastTimeInHistory;
};

#endif // TRAILMGR_HPP