qglframebufferobject.cpp

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/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtOpenGL module of the Qt Toolkit.
**
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** General Public License version 2.1 as published by the Free Software
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#include "qglframebufferobject.h"
#include "qglframebufferobject_p.h"

#include <qdebug.h>
#include <private/qgl_p.h>
#include <private/qfont_p.h>
#if !defined(QT_OPENGL_ES_1)
#include <private/qpaintengineex_opengl2_p.h>
#endif

#ifndef QT_OPENGL_ES_2
#include <private/qpaintengine_opengl_p.h>
#endif

#include <qglframebufferobject.h>
#include <qlibrary.h>
#include <qimage.h>

QT_BEGIN_NAMESPACE

extern QImage qt_gl_read_framebuffer(const QSize&, bool, bool);

#define QGL_FUNC_CONTEXT const QGLContext *ctx = d_ptr->fbo_guard.context();
#define QGL_FUNCP_CONTEXT const QGLContext *ctx = fbo_guard.context();

#ifndef QT_NO_DEBUG
#define QT_RESET_GLERROR()                                \
{                                                         \
    while (glGetError() != GL_NO_ERROR) {}                \
}
#define QT_CHECK_GLERROR()                                \
{                                                         \
    GLenum err = glGetError();                            \
    if (err != GL_NO_ERROR) {                             \
        qDebug("[%s line %d] GL Error: %d",               \
               __FILE__, __LINE__, (int)err);             \
    }                                                     \
}
#else
#define QT_RESET_GLERROR() {}
#define QT_CHECK_GLERROR() {}
#endif

void QGLFramebufferObjectFormat::detach()
{
    if (d->ref != 1) {
        QGLFramebufferObjectFormatPrivate *newd
            = new QGLFramebufferObjectFormatPrivate(d);
        if (!d->ref.deref())
            delete d;
        d = newd;
    }
}

QGLFramebufferObjectFormat::QGLFramebufferObjectFormat()
{
    d = new QGLFramebufferObjectFormatPrivate;
}

QGLFramebufferObjectFormat::QGLFramebufferObjectFormat(const QGLFramebufferObjectFormat &other)
{
    d = other.d;
    d->ref.ref();
}

QGLFramebufferObjectFormat &QGLFramebufferObjectFormat::operator=(const QGLFramebufferObjectFormat &other)
{
    if (d != other.d) {
        other.d->ref.ref();
        if (!d->ref.deref())
            delete d;
        d = other.d;
    }
    return *this;
}

QGLFramebufferObjectFormat::~QGLFramebufferObjectFormat()
{
    if (!d->ref.deref())
        delete d;
}

void QGLFramebufferObjectFormat::setSamples(int samples)
{
    detach();
    d->samples = samples;
}

int QGLFramebufferObjectFormat::samples() const
{
    return d->samples;
}

void QGLFramebufferObjectFormat::setMipmap(bool enabled)
{
    detach();
    d->mipmap = enabled;
}

bool QGLFramebufferObjectFormat::mipmap() const
{
    return d->mipmap;
}

void QGLFramebufferObjectFormat::setAttachment(QGLFramebufferObject::Attachment attachment)
{
    detach();
    d->attachment = attachment;
}

QGLFramebufferObject::Attachment QGLFramebufferObjectFormat::attachment() const
{
    return d->attachment;
}

void QGLFramebufferObjectFormat::setTextureTarget(GLenum target)
{
    detach();
    d->target = target;
}

GLenum QGLFramebufferObjectFormat::textureTarget() const
{
    return d->target;
}

void QGLFramebufferObjectFormat::setInternalTextureFormat(GLenum internalTextureFormat)
{
    detach();
    d->internal_format = internalTextureFormat;
}

GLenum QGLFramebufferObjectFormat::internalTextureFormat() const
{
    return d->internal_format;
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

void QGLFramebufferObjectFormat::setTextureTarget(QMacCompatGLenum target)
{
    detach();
    d->target = target;
}

void QGLFramebufferObjectFormat::setInternalTextureFormat(QMacCompatGLenum internalTextureFormat)
{
    detach();
    d->internal_format = internalTextureFormat;
}
#endif

bool QGLFramebufferObjectFormat::operator==(const QGLFramebufferObjectFormat& other) const
{
    if (d == other.d)
        return true;
    else
        return d->equals(other.d);
}

bool QGLFramebufferObjectFormat::operator!=(const QGLFramebufferObjectFormat& other) const
{
    return !(*this == other);
}

void QGLFBOGLPaintDevice::setFBO(QGLFramebufferObject* f,
                                 QGLFramebufferObject::Attachment attachment)
{
    fbo = f;
    m_thisFBO = fbo->d_func()->fbo(); // This shouldn't be needed

    // The context that the fbo was created in may not have depth
    // and stencil buffers, but the fbo itself might.
    fboFormat = QGLContext::currentContext()->format();
    if (attachment == QGLFramebufferObject::CombinedDepthStencil) {
        fboFormat.setDepth(true);
        fboFormat.setStencil(true);
    } else if (attachment == QGLFramebufferObject::Depth) {
        fboFormat.setDepth(true);
        fboFormat.setStencil(false);
    } else {
        fboFormat.setDepth(false);
        fboFormat.setStencil(false);
    }

    GLenum format = f->format().internalTextureFormat();
    reqAlpha = (format != GL_RGB
#ifndef QT_OPENGL_ES
                && format != GL_RGB5 && format != GL_RGB8
#endif
    );
}

QGLContext *QGLFBOGLPaintDevice::context() const
{
    QGLContext *fboContext = const_cast<QGLContext *>(fbo->d_ptr->fbo_guard.context());
    QGLContext *currentContext = const_cast<QGLContext *>(QGLContext::currentContext());

    if (QGLContextPrivate::contextGroup(fboContext) == QGLContextPrivate::contextGroup(currentContext))
        return currentContext;
    else
        return fboContext;
}

bool QGLFramebufferObjectPrivate::checkFramebufferStatus() const
{
    QGL_FUNCP_CONTEXT;
    if (!ctx)
        return false;   // Context no longer exists.
    GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER_EXT);
    switch(status) {
    case GL_NO_ERROR:
    case GL_FRAMEBUFFER_COMPLETE_EXT:
        return true;
        break;
    case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
        qDebug("QGLFramebufferObject: Unsupported framebuffer format.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete attachment.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, missing attachment.");
        break;
#ifdef GL_FRAMEBUFFER_INCOMPLETE_DUPLICATE_ATTACHMENT_EXT
    case GL_FRAMEBUFFER_INCOMPLETE_DUPLICATE_ATTACHMENT_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, duplicate attachment.");
        break;
#endif
    case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, attached images must have same dimensions.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, attached images must have same format.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, missing draw buffer.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, missing read buffer.");
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
        qDebug("QGLFramebufferObject: Framebuffer incomplete, attachments must have same number of samples per pixel.");
        break;
    default:
        qDebug() <<"QGLFramebufferObject: An undefined error has occurred: "<< status;
        break;
    }
    return false;
}

void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
                                       QGLFramebufferObject::Attachment attachment,
                                       GLenum texture_target, GLenum internal_format,
                                       GLint samples, bool mipmap)
{
    QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
    fbo_guard.setContext(ctx);

    bool ext_detected = (QGLExtensions::glExtensions() & QGLExtensions::FramebufferObject);
    if (!ext_detected || (ext_detected && !qt_resolve_framebufferobject_extensions(ctx)))
        return;

    size = sz;
    target = texture_target;
    // texture dimensions

    QT_RESET_GLERROR(); // reset error state
    GLuint fbo = 0;
    glGenFramebuffers(1, &fbo);
    glBindFramebuffer(GL_FRAMEBUFFER_EXT, fbo);
    fbo_guard.setId(fbo);

    glDevice.setFBO(q, attachment);

    QT_CHECK_GLERROR();
    // init texture
    if (samples == 0) {
        glGenTextures(1, &texture);
        glBindTexture(target, texture);
        glTexImage2D(target, 0, internal_format, size.width(), size.height(), 0,
                GL_RGBA, GL_UNSIGNED_BYTE, NULL);
        if (mipmap)
            glGenerateMipmap(GL_TEXTURE_2D);
#ifndef QT_OPENGL_ES
        glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
#else
        glTexParameterf(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameterf(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameterf(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameterf(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
#endif
        glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                target, texture, 0);

        QT_CHECK_GLERROR();
        valid = checkFramebufferStatus();
        glBindTexture(target, 0);

        color_buffer = 0;
    } else {
        mipmap = false;
        GLint maxSamples;
        glGetIntegerv(GL_MAX_SAMPLES_EXT, &maxSamples);

        samples = qBound(0, int(samples), int(maxSamples));

        glGenRenderbuffers(1, &color_buffer);
        glBindRenderbuffer(GL_RENDERBUFFER_EXT, color_buffer);
        if (glRenderbufferStorageMultisampleEXT && samples > 0) {
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                internal_format, size.width(), size.height());
        } else {
            samples = 0;
            glRenderbufferStorage(GL_RENDERBUFFER_EXT, internal_format,
                size.width(), size.height());
        }

        glFramebufferRenderbuffer(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                                     GL_RENDERBUFFER_EXT, color_buffer);

        QT_CHECK_GLERROR();
        valid = checkFramebufferStatus();

        if (valid)
            glGetRenderbufferParameteriv(GL_RENDERBUFFER_EXT, GL_RENDERBUFFER_SAMPLES_EXT, &samples);
    }

    // In practice, a combined depth-stencil buffer is supported by all desktop platforms, while a
    // separate stencil buffer is not. On embedded devices however, a combined depth-stencil buffer
    // might not be supported while separate buffers are, according to QTBUG-12861.

    if (attachment == QGLFramebufferObject::CombinedDepthStencil
        && (QGLExtensions::glExtensions() & QGLExtensions::PackedDepthStencil)) {
        // depth and stencil buffer needs another extension
        glGenRenderbuffers(1, &depth_buffer);
        Q_ASSERT(!glIsRenderbuffer(depth_buffer));
        glBindRenderbuffer(GL_RENDERBUFFER_EXT, depth_buffer);
        Q_ASSERT(glIsRenderbuffer(depth_buffer));
        if (samples != 0 && glRenderbufferStorageMultisampleEXT)
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                GL_DEPTH24_STENCIL8_EXT, size.width(), size.height());
        else
            glRenderbufferStorage(GL_RENDERBUFFER_EXT,
                GL_DEPTH24_STENCIL8_EXT, size.width(), size.height());

        stencil_buffer = depth_buffer;
        glFramebufferRenderbuffer(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
                                     GL_RENDERBUFFER_EXT, depth_buffer);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
                                     GL_RENDERBUFFER_EXT, stencil_buffer);

        valid = checkFramebufferStatus();
        if (!valid) {
            glDeleteRenderbuffers(1, &depth_buffer);
            stencil_buffer = depth_buffer = 0;
        }
    }

    if (depth_buffer == 0 && (attachment == QGLFramebufferObject::CombinedDepthStencil
        || (attachment == QGLFramebufferObject::Depth)))
    {
        glGenRenderbuffers(1, &depth_buffer);
        Q_ASSERT(!glIsRenderbuffer(depth_buffer));
        glBindRenderbuffer(GL_RENDERBUFFER_EXT, depth_buffer);
        Q_ASSERT(glIsRenderbuffer(depth_buffer));
        if (samples != 0 && glRenderbufferStorageMultisampleEXT) {
#ifdef QT_OPENGL_ES
            if (QGLExtensions::glExtensions() & QGLExtensions::Depth24) {
                glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                    GL_DEPTH_COMPONENT24_OES, size.width(), size.height());
            } else {
                glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                    GL_DEPTH_COMPONENT16, size.width(), size.height());
            }
#else
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                GL_DEPTH_COMPONENT, size.width(), size.height());
#endif
        } else {
#ifdef QT_OPENGL_ES
            if (QGLExtensions::glExtensions() & QGLExtensions::Depth24) {
                glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24_OES, 
                                        size.width(), size.height());
            } else {
                glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT16, 
                                        size.width(), size.height());
            }
#else
            glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, size.width(), size.height());
#endif
        }
        glFramebufferRenderbuffer(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
                                     GL_RENDERBUFFER_EXT, depth_buffer);
        valid = checkFramebufferStatus();
        if (!valid) {
            glDeleteRenderbuffers(1, &depth_buffer);
            depth_buffer = 0;
        }
    }

    if (stencil_buffer == 0 && (attachment == QGLFramebufferObject::CombinedDepthStencil)) {
        glGenRenderbuffers(1, &stencil_buffer);
        Q_ASSERT(!glIsRenderbuffer(stencil_buffer));
        glBindRenderbuffer(GL_RENDERBUFFER_EXT, stencil_buffer);
        Q_ASSERT(glIsRenderbuffer(stencil_buffer));
        if (samples != 0 && glRenderbufferStorageMultisampleEXT) {
#ifdef QT_OPENGL_ES
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                GL_STENCIL_INDEX8_EXT, size.width(), size.height());
#else
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER_EXT, samples,
                GL_STENCIL_INDEX, size.width(), size.height());
#endif
        } else {
#ifdef QT_OPENGL_ES
            glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX8_EXT,
                                  size.width(), size.height());
#else
            glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX,
                                  size.width(), size.height());
#endif
        }
        glFramebufferRenderbuffer(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
                                  GL_RENDERBUFFER_EXT, stencil_buffer);
        valid = checkFramebufferStatus();
        if (!valid) {
            glDeleteRenderbuffers(1, &stencil_buffer);
            stencil_buffer = 0;
        }
    }

    // The FBO might have become valid after removing the depth or stencil buffer.
    valid = checkFramebufferStatus();

    if (depth_buffer && stencil_buffer) {
        fbo_attachment = QGLFramebufferObject::CombinedDepthStencil;
    } else if (depth_buffer) {
        fbo_attachment = QGLFramebufferObject::Depth;
    } else {
        fbo_attachment = QGLFramebufferObject::NoAttachment;
    }

    glBindFramebuffer(GL_FRAMEBUFFER_EXT, ctx->d_ptr->current_fbo);
    if (!valid) {
        if (color_buffer)
            glDeleteRenderbuffers(1, &color_buffer);
        else
            glDeleteTextures(1, &texture);
        if (depth_buffer)
            glDeleteRenderbuffers(1, &depth_buffer);
        if (stencil_buffer && depth_buffer != stencil_buffer)
            glDeleteRenderbuffers(1, &stencil_buffer);
        glDeleteFramebuffers(1, &fbo);
        fbo_guard.setId(0);
    }
    QT_CHECK_GLERROR();

    format.setTextureTarget(target);
    format.setSamples(int(samples));
    format.setAttachment(fbo_attachment);
    format.setInternalTextureFormat(internal_format);
    format.setMipmap(mipmap);
}

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, GLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, size, NoAttachment, target, DEFAULT_FORMAT);
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, QMacCompatGLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, size, NoAttachment, target, DEFAULT_FORMAT);
}
#endif

QGLFramebufferObject::QGLFramebufferObject(int width, int height, GLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, QSize(width, height), NoAttachment, target, DEFAULT_FORMAT);
}

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, const QGLFramebufferObjectFormat &format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, size, format.attachment(), format.textureTarget(), format.internalTextureFormat(),
            format.samples(), format.mipmap());
}

QGLFramebufferObject::QGLFramebufferObject(int width, int height, const QGLFramebufferObjectFormat &format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, QSize(width, height), format.attachment(), format.textureTarget(),
            format.internalTextureFormat(), format.samples(), format.mipmap());
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

QGLFramebufferObject::QGLFramebufferObject(int width, int height, QMacCompatGLenum target)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, QSize(width, height), NoAttachment, target, DEFAULT_FORMAT);
}
#endif

QGLFramebufferObject::QGLFramebufferObject(int width, int height, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, QSize(width, height), attachment, target, internal_format);
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

QGLFramebufferObject::QGLFramebufferObject(int width, int height, Attachment attachment,
                                           QMacCompatGLenum target, QMacCompatGLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, QSize(width, height), attachment, target, internal_format);
}
#endif

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, Attachment attachment,
                                           GLenum target, GLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, size, attachment, target, internal_format);
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

QGLFramebufferObject::QGLFramebufferObject(const QSize &size, Attachment attachment,
                                           QMacCompatGLenum target, QMacCompatGLenum internal_format)
    : d_ptr(new QGLFramebufferObjectPrivate)
{
    Q_D(QGLFramebufferObject);
    d->init(this, size, attachment, target, internal_format);
}
#endif

QGLFramebufferObject::~QGLFramebufferObject()
{
    Q_D(QGLFramebufferObject);
    QGL_FUNC_CONTEXT;

    delete d->engine;

    if (isValid() && ctx) {
        QGLShareContextScope scope(ctx);
        if (d->texture)
            glDeleteTextures(1, &d->texture);
        if (d->color_buffer)
            glDeleteRenderbuffers(1, &d->color_buffer);
        if (d->depth_buffer)
            glDeleteRenderbuffers(1, &d->depth_buffer);
        if (d->stencil_buffer && d->stencil_buffer != d->depth_buffer)
            glDeleteRenderbuffers(1, &d->stencil_buffer);
        GLuint fbo = d->fbo();
        glDeleteFramebuffers(1, &fbo);
    }
}

bool QGLFramebufferObject::isValid() const
{
    Q_D(const QGLFramebufferObject);
    return d->valid && d->fbo_guard.context();
}

bool QGLFramebufferObject::bind()
{
    if (!isValid())
    return false;
    Q_D(QGLFramebufferObject);
    QGL_FUNC_CONTEXT;
    if (!ctx)
        return false;   // Context no longer exists.
    const QGLContext *current = QGLContext::currentContext();
#ifdef QT_DEBUG
    if (!current ||
        QGLContextPrivate::contextGroup(current) != QGLContextPrivate::contextGroup(ctx))
    {
        qWarning("QGLFramebufferObject::bind() called from incompatible context");
    }
#endif
    glBindFramebuffer(GL_FRAMEBUFFER_EXT, d->fbo());
    d->valid = d->checkFramebufferStatus();
    if (d->valid && current)
        current->d_ptr->current_fbo = d->fbo();
    return d->valid;
}

bool QGLFramebufferObject::release()
{
    if (!isValid())
    return false;
    QGL_FUNC_CONTEXT;
    if (!ctx)
        return false;   // Context no longer exists.

    const QGLContext *current = QGLContext::currentContext();

#ifdef QT_DEBUG
    if (!current ||
        QGLContextPrivate::contextGroup(current) != QGLContextPrivate::contextGroup(ctx))
    {
        qWarning("QGLFramebufferObject::release() called from incompatible context");
    }
#endif

    if (current) {
        current->d_ptr->current_fbo = current->d_ptr->default_fbo;
        glBindFramebuffer(GL_FRAMEBUFFER_EXT, current->d_ptr->default_fbo);
    }

    return true;
}

GLuint QGLFramebufferObject::texture() const
{
    Q_D(const QGLFramebufferObject);
    return d->texture;
}

QSize QGLFramebufferObject::size() const
{
    Q_D(const QGLFramebufferObject);
    return d->size;
}

QGLFramebufferObjectFormat QGLFramebufferObject::format() const
{
    Q_D(const QGLFramebufferObject);
    return d->format;
}

QImage QGLFramebufferObject::toImage() const
{
    Q_D(const QGLFramebufferObject);
    if (!d->valid)
        return QImage();

    // qt_gl_read_framebuffer doesn't work on a multisample FBO
    if (format().samples() != 0) {
        QGLFramebufferObject temp(size(), QGLFramebufferObjectFormat());

        QRect rect(QPoint(0, 0), size());
        blitFramebuffer(&temp, rect, const_cast<QGLFramebufferObject *>(this), rect);

        return temp.toImage();
    }

    bool wasBound = isBound();
    if (!wasBound)
        const_cast<QGLFramebufferObject *>(this)->bind();
    QImage image = qt_gl_read_framebuffer(d->size, format().internalTextureFormat() != GL_RGB, true);
    if (!wasBound)
        const_cast<QGLFramebufferObject *>(this)->release();

    return image;
}

#if !defined(QT_OPENGL_ES_1)
Q_GLOBAL_STATIC(QGLEngineThreadStorage<QGL2PaintEngineEx>, qt_buffer_2_engine)
#endif

#ifndef QT_OPENGL_ES_2
Q_GLOBAL_STATIC(QGLEngineThreadStorage<QOpenGLPaintEngine>, qt_buffer_engine)
#endif

QPaintEngine *QGLFramebufferObject::paintEngine() const
{
    Q_D(const QGLFramebufferObject);
    if (d->engine)
        return d->engine;

#if !defined(QT_OPENGL_ES_1)
#if !defined (QT_OPENGL_ES_2)
    if (qt_gl_preferGL2Engine()) {
#endif
        QPaintEngine *engine = qt_buffer_2_engine()->engine();
        if (engine->isActive() && engine->paintDevice() != this) {
            d->engine = new QGL2PaintEngineEx;
            return d->engine;
        }
        return engine;
#if !defined (QT_OPENGL_ES_2)
    }
#endif
#endif

#if !defined(QT_OPENGL_ES_2)
    QPaintEngine *engine = qt_buffer_engine()->engine();
    if (engine->isActive() && engine->paintDevice() != this) {
        d->engine = new QOpenGLPaintEngine;
        return d->engine;
    }
    return engine;
#endif
}

bool QGLFramebufferObject::bindDefault()
{
    QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());

    if (ctx) {
        bool ext_detected = (QGLExtensions::glExtensions() & QGLExtensions::FramebufferObject);
        if (!ext_detected || (ext_detected && !qt_resolve_framebufferobject_extensions(ctx)))
            return false;

        ctx->d_ptr->current_fbo = ctx->d_ptr->default_fbo;
        glBindFramebuffer(GL_FRAMEBUFFER_EXT, ctx->d_ptr->default_fbo);
#ifdef QT_DEBUG
    } else {
        qWarning("QGLFramebufferObject::bindDefault() called without current context.");
#endif
    }

    return ctx != 0;
}

bool QGLFramebufferObject::hasOpenGLFramebufferObjects()
{
    return (QGLExtensions::glExtensions() & QGLExtensions::FramebufferObject);
}

void QGLFramebufferObject::drawTexture(const QRectF &target, GLuint textureId, GLenum textureTarget)
{
    const_cast<QGLContext *>(QGLContext::currentContext())->drawTexture(target, textureId, textureTarget);
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

void QGLFramebufferObject::drawTexture(const QRectF &target, QMacCompatGLuint textureId, QMacCompatGLenum textureTarget)
{
    const_cast<QGLContext *>(QGLContext::currentContext())->drawTexture(target, textureId, textureTarget);
}
#endif

void QGLFramebufferObject::drawTexture(const QPointF &point, GLuint textureId, GLenum textureTarget)
{
    const_cast<QGLContext *>(QGLContext::currentContext())->drawTexture(point, textureId, textureTarget);
}

#ifdef Q_MAC_COMPAT_GL_FUNCTIONS

void QGLFramebufferObject::drawTexture(const QPointF &point, QMacCompatGLuint textureId, QMacCompatGLenum textureTarget)
{
    const_cast<QGLContext *>(QGLContext::currentContext())->drawTexture(point, textureId, textureTarget);
}
#endif

int QGLFramebufferObject::metric(PaintDeviceMetric metric) const
{
    Q_D(const QGLFramebufferObject);

    float dpmx = qt_defaultDpiX()*100./2.54;
    float dpmy = qt_defaultDpiY()*100./2.54;
    int w = d->size.width();
    int h = d->size.height();
    switch (metric) {
    case PdmWidth:
        return w;

    case PdmHeight:
        return h;

    case PdmWidthMM:
        return qRound(w * 1000 / dpmx);

    case PdmHeightMM:
        return qRound(h * 1000 / dpmy);

    case PdmNumColors:
        return 0;

    case PdmDepth:
        return 32;//d->depth;

    case PdmDpiX:
        return qRound(dpmx * 0.0254);

    case PdmDpiY:
        return qRound(dpmy * 0.0254);

    case PdmPhysicalDpiX:
        return qRound(dpmx * 0.0254);

    case PdmPhysicalDpiY:
        return qRound(dpmy * 0.0254);

    default:
        qWarning("QGLFramebufferObject::metric(), Unhandled metric type: %d.\n", metric);
        break;
    }
    return 0;
}

GLuint QGLFramebufferObject::handle() const
{
    Q_D(const QGLFramebufferObject);
    return d->fbo();
}

QGLFramebufferObject::Attachment QGLFramebufferObject::attachment() const
{
    Q_D(const QGLFramebufferObject);
    if (d->valid)
        return d->fbo_attachment;
    return NoAttachment;
}

bool QGLFramebufferObject::isBound() const
{
    Q_D(const QGLFramebufferObject);
    const QGLContext *current = QGLContext::currentContext();
    return current ? current->d_ptr->current_fbo == d->fbo() : false;
}

bool QGLFramebufferObject::hasOpenGLFramebufferBlit()
{
    return (QGLExtensions::glExtensions() & QGLExtensions::FramebufferBlit);
}

void QGLFramebufferObject::blitFramebuffer(QGLFramebufferObject *target, const QRect &targetRect,
                                           QGLFramebufferObject *source, const QRect &sourceRect,
                                           GLbitfield buffers,
                                           GLenum filter)
{
    if (!(QGLExtensions::glExtensions() & QGLExtensions::FramebufferBlit))
        return;

    const QGLContext *ctx = QGLContext::currentContext();
    if (!ctx)
        return;

    const int height = ctx->device()->height();

    const int sh = source ? source->height() : height;
    const int th = target ? target->height() : height;

    const int sx0 = sourceRect.left();
    const int sx1 = sourceRect.left() + sourceRect.width();
    const int sy0 = sh - (sourceRect.top() + sourceRect.height());
    const int sy1 = sh - sourceRect.top();

    const int tx0 = targetRect.left();
    const int tx1 = targetRect.left() + targetRect.width();
    const int ty0 = th - (targetRect.top() + targetRect.height());
    const int ty1 = th - targetRect.top();

    glBindFramebuffer(GL_READ_FRAMEBUFFER_EXT, source ? source->handle() : 0);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER_EXT, target ? target->handle() : 0);

    glBlitFramebufferEXT(sx0, sy0, sx1, sy1,
                         tx0, ty0, tx1, ty1,
                         buffers, filter);

    glBindFramebuffer(GL_FRAMEBUFFER_EXT, ctx->d_ptr->current_fbo);
}

QT_END_NAMESPACE