/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtOpenGL module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QTEXTUREGLYPHCACHE_GL_P_H
#define QTEXTUREGLYPHCACHE_GL_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of the QLibrary class.  This header file may change from
// version to version without notice, or even be removed.
//
// We mean it.
//

#include <private/qtextureglyphcache_p.h>
#include <private/qgl_p.h>
#include <qglshaderprogram.h>

// #define QT_GL_TEXTURE_GLYPH_CACHE_DEBUG

QT_BEGIN_NAMESPACE

class QGL2PaintEngineExPrivate;

struct QGLGlyphTexture
{
    QGLGlyphTexture(const QGLContext *ctx)
        : m_width(0)
        , m_height(0)
    {
        if (ctx && !ctx->d_ptr->workaround_brokenFBOReadBack)
            glGenFramebuffers(1, &m_fbo);

#ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
        qDebug(" -> QGLGlyphTexture() %p for context %p.", this, ctx);
#endif
    }

    ~QGLGlyphTexture() {
        const QGLContext *ctx = QGLContext::currentContext();
#ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
        qDebug("~QGLGlyphTexture() %p for context %p.", this, ctx);
#endif
        // At this point, the context group is made current, so it's safe to
        // release resources without a makeCurrent() call
        if (ctx) {
            if (!ctx->d_ptr->workaround_brokenFBOReadBack)
                glDeleteFramebuffers(1, &m_fbo);
            if (m_width || m_height)
                glDeleteTextures(1, &m_texture);
        }
    }

    GLuint m_texture;
    GLuint m_fbo;
    int m_width;
    int m_height;
};

class Q_OPENGL_EXPORT QGLTextureGlyphCache : public QImageTextureGlyphCache, public QGLContextGroupResourceBase
{
public:
    QGLTextureGlyphCache(const QGLContext *context, QFontEngineGlyphCache::Type type, const QTransform &matrix);
    ~QGLTextureGlyphCache();

    virtual void createTextureData(int width, int height);
    virtual void resizeTextureData(int width, int height);
    virtual void fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition);
    virtual int glyphPadding() const;
    virtual int maxTextureWidth() const;
    virtual int maxTextureHeight() const;

    inline GLuint texture() const {
        QGLTextureGlyphCache *that = const_cast<QGLTextureGlyphCache *>(this);
        QGLGlyphTexture *glyphTexture = that->m_textureResource.value(ctx);
        return glyphTexture ? glyphTexture->m_texture : 0;
    }

    inline int width() const {
        QGLTextureGlyphCache *that = const_cast<QGLTextureGlyphCache *>(this);
        QGLGlyphTexture *glyphTexture = that->m_textureResource.value(ctx);
        return glyphTexture ? glyphTexture->m_width : 0;
    }
    inline int height() const {
        QGLTextureGlyphCache *that = const_cast<QGLTextureGlyphCache *>(this);
        QGLGlyphTexture *glyphTexture = that->m_textureResource.value(ctx);
        return glyphTexture ? glyphTexture->m_height : 0;
    }

    inline void setPaintEnginePrivate(QGL2PaintEngineExPrivate *p) { pex = p; }

    void setContext(const QGLContext *context);
    inline const QGLContext *context() const { return ctx; }

    enum FilterMode {
        Nearest,
        Linear
    };
    FilterMode filterMode() const { return m_filterMode; }
    void setFilterMode(FilterMode m) { m_filterMode = m; }

    void freeResource(void *) { ctx = 0; }

private:
    QGLContextGroupResource<QGLGlyphTexture> m_textureResource;

    const QGLContext *ctx;
    QGL2PaintEngineExPrivate *pex;
    QGLShaderProgram *m_blitProgram;
    FilterMode m_filterMode;

    GLfloat m_vertexCoordinateArray[8];
    GLfloat m_textureCoordinateArray[8];
};

QT_END_NAMESPACE

#endif