StelQGLTextureBackend.hpp

/*
 * Stellarium
 * Copyright (C) 2012 Ferdinand Majerech
 *
 * 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 _STELQGLTEXTUREBACKEND_HPP_
#define _STELQGLTEXTUREBACKEND_HPP_

#include "StelGLUtilityFunctions.hpp"
#include "StelRenderer.hpp"
#include "StelTextureBackend.hpp"


class StelQGLTextureBackend : public StelTextureBackend
{
Q_OBJECT
public:
    ~StelQGLTextureBackend();
    
    void bind(const int textureUnit);
    
    void startAsynchronousLoading();
    
    static StelQGLTextureBackend* constructFromImage
        (class StelQGLRenderer* renderer, const QString& path, 
         const TextureParams& params, QImage& image);
    
    static StelQGLTextureBackend* constructFromPVR
        (class StelQGLRenderer* renderer, const QString& path, const TextureParams& params);

    static StelQGLTextureBackend* constructAsynchronous
        (class StelQGLRenderer* renderer, const QString& path, const TextureParams& params);
    
    static StelQGLTextureBackend* fromFBO
        (StelQGLRenderer* renderer, class QGLFramebufferObject* fbo);

    static StelQGLTextureBackend* fromViewport
        (StelQGLRenderer* renderer, const QSize viewportSize, const QGLFormat& viewportFormat);

    static StelQGLTextureBackend* fromRawData
        (StelQGLRenderer* renderer, const void* data, const QSize size, 
         const TextureDataFormat format, const TextureParams& params);
private slots:
    void onImageLoaded(QImage image);
    
    void onLoadingError(const QString& errorMessage) ;
    
private:
    TextureParams textureParams;

    class StelQGLRenderer* renderer;

    GLuint glTextureID;

    bool ownsTexture;
    
    bool deleteManually;

    class StelTextureLoader* loader;

    float pixelBytes;

    StelQGLTextureBackend(class StelQGLRenderer* renderer, const QString& path, 
                          const TextureParams& params);

    void loadFromImage(QImage image);

    void loadFromPVR();
    
    QGLContext* prepareContextForLoading();
    
    void completeLoading();
    
    void setTextureWrapping();
    
    void invariant() const
    {
#ifndef NDEBUG
        const TextureStatus status = getStatus();
        if((glTextureID != 0) != (status == TextureStatus_Loaded))
        {
            qDebug() << "Handle: " << glTextureID << " Status: " << textureStatusName(status);
            Q_ASSERT_X(false, Q_FUNC_INFO, "Texture can be specified if and only if loaded.");
        }

        Q_ASSERT_X(loader == NULL || status == TextureStatus_Loading,
                   Q_FUNC_INFO, "Texture loader can only exist during loading");
#endif
    }
};
#endif // _STELQGLTEXTUREBACKEND_HPP_