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#include "qioscontext.h"
#include "qioswindow.h"

#include <dlfcn.h>

#include <QtGui/QOpenGlContext>

#import <OpenGLES/EAGL.h>
#import <QuartzCore/CAEAGLLayer.h>

QIOSContext::QIOSContext(QOpenGLContext *context)
    : QPlatformOpenGLContext()
    , m_eaglContext([[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2])
{
    // Start out with the requested format
    QSurfaceFormat format = context->format();

    format.setRenderableType(QSurfaceFormat::OpenGLES);
    format.setMajorVersion(2);
    format.setMinorVersion(0);

    // Even though iOS internally double-buffers its rendering, we
    // report single-buffered here since the buffer remains unchanged
    // when swapping unlesss you manually clear it yourself.
    format.setSwapBehavior(QSurfaceFormat::SingleBuffer);

    m_format = format;
}

QIOSContext::~QIOSContext()
{
    if ([EAGLContext currentContext] == m_eaglContext)
        doneCurrent();

    [m_eaglContext release];
}

QSurfaceFormat QIOSContext::format() const
{
    return m_format;
}

bool QIOSContext::makeCurrent(QPlatformSurface *surface)
{
    Q_ASSERT(surface && surface->surface()->surfaceType() == QSurface::OpenGLSurface);

    [EAGLContext setCurrentContext:m_eaglContext];
    glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebufferObject(surface));

    // Ensures render buffers are set up and match the size of the window
    return defaultColorRenderbuffer(surface) != 0;
}

void QIOSContext::doneCurrent()
{
    [EAGLContext setCurrentContext:nil];
}

void QIOSContext::swapBuffers(QPlatformSurface *surface)
{
    Q_ASSERT(surface && surface->surface()->surfaceType() == QSurface::OpenGLSurface);

    [EAGLContext setCurrentContext:m_eaglContext];
    glBindRenderbuffer(GL_RENDERBUFFER, defaultColorRenderbuffer(surface));
    [m_eaglContext presentRenderbuffer:GL_RENDERBUFFER];
}

GLuint QIOSContext::defaultFramebufferObject(QPlatformSurface *surface) const
{
    return static_cast<QIOSWindow *>(surface)->framebufferObject(*const_cast<const QIOSContext*>(this));
}

GLuint QIOSContext::defaultColorRenderbuffer(QPlatformSurface *surface) const
{
    return static_cast<QIOSWindow *>(surface)->colorRenderbuffer(*const_cast<const QIOSContext*>(this));
}

QFunctionPointer QIOSContext::getProcAddress(const QByteArray& functionName)
{
    return reinterpret_cast<QFunctionPointer>(dlsym(RTLD_NEXT, functionName.constData()));
}

EAGLContext *QIOSContext::nativeContext() const
{
    return m_eaglContext;
}