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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
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#include <QtGui/qpaintdevice.h>
#include <QtGui/qpixmap.h>
#include <QtGui/qwidget.h>
#include <QtCore/qatomic.h>
#include <QtCore/qdebug.h>
#include "qegl_p.h"

QT_BEGIN_NAMESPACE


/*
    QEglContextTracker is used to track the EGL contexts that we
    create internally in Qt, so that we can call eglTerminate() to
    free additional EGL resources when the last context is destroyed.
*/

class QEglContextTracker
{
public:
    static void ref() { contexts.ref(); }
    static void deref() {
        if (!contexts.deref()) {
            eglTerminate(QEglContext::display());
            displayOpen = 0;
        }
    }
    static void setDisplayOpened() { displayOpen = 1; }
    static bool displayOpened() { return displayOpen; }

private:
    static QBasicAtomicInt contexts;
    static QBasicAtomicInt displayOpen;
};

QBasicAtomicInt QEglContextTracker::contexts = Q_BASIC_ATOMIC_INITIALIZER(0);
QBasicAtomicInt QEglContextTracker::displayOpen = Q_BASIC_ATOMIC_INITIALIZER(0);

// Current GL and VG contexts.  These are used to determine if
// we can avoid an eglMakeCurrent() after a call to lazyDoneCurrent().
// If a background thread modifies the value, the worst that will
// happen is a redundant eglMakeCurrent() in the foreground thread.
static QEglContext * volatile currentGLContext = 0;
static QEglContext * volatile currentVGContext = 0;

EGLDisplay QEglContext::dpy = EGL_NO_DISPLAY;

QEglContext::QEglContext()
    : apiType(QEgl::OpenGL)
    , ctx(EGL_NO_CONTEXT)
    , cfg(0)
    , currentSurface(EGL_NO_SURFACE)
    , current(false)
    , ownsContext(true)
    , sharing(false)
{
    QEglContextTracker::ref();
}

QEglContext::~QEglContext()
{
    destroyContext();

    if (currentGLContext == this)
        currentGLContext = 0;
    if (currentVGContext == this)
        currentVGContext = 0;
    QEglContextTracker::deref();
}

bool QEglContext::isValid() const
{
    return (ctx != EGL_NO_CONTEXT);
}

bool QEglContext::isCurrent() const
{
    return current;
}

// Choose a configuration that matches "properties".
bool QEglContext::chooseConfig
        (const QEglProperties& properties, QEgl::PixelFormatMatch match)
{
    QEglProperties props(properties);
    do {
        // Get the number of matching configurations for this set of properties.
        EGLint matching = 0;
        if (!eglChooseConfig(display(), props.properties(), 0, 0, &matching) || !matching)
            continue;

        // If we want the best pixel format, then return the first
        // matching configuration.
        if (match == QEgl::BestPixelFormat) {
            eglChooseConfig(display(), props.properties(), &cfg, 1, &matching);
            if (matching < 1)
                continue;
            return true;
        }

        // Fetch all of the matching configurations and find the
        // first that matches the pixel format we wanted.
        EGLint size = matching;
        EGLConfig *configs = new EGLConfig [size];
        eglChooseConfig(display(), props.properties(), configs, size, &matching);
        for (EGLint index = 0; index < size; ++index) {
            EGLint red, green, blue, alpha;
            eglGetConfigAttrib(display(), configs[index], EGL_RED_SIZE, &red);
            eglGetConfigAttrib(display(), configs[index], EGL_GREEN_SIZE, &green);
            eglGetConfigAttrib(display(), configs[index], EGL_BLUE_SIZE, &blue);
            eglGetConfigAttrib(display(), configs[index], EGL_ALPHA_SIZE, &alpha);
            if (red == props.value(EGL_RED_SIZE) &&
                    green == props.value(EGL_GREEN_SIZE) &&
                    blue == props.value(EGL_BLUE_SIZE) &&
                    (props.value(EGL_ALPHA_SIZE) == 0 ||
                     alpha == props.value(EGL_ALPHA_SIZE))) {
                cfg = configs[index];
                delete [] configs;
                return true;
            }
        }
        delete [] configs;
    } while (props.reduceConfiguration());

#ifdef EGL_BIND_TO_TEXTURE_RGBA
    // Don't report an error just yet if we failed to get a pbuffer
    // configuration with texture rendering.  Only report failure if
    // we cannot get any pbuffer configurations at all.
    if (props.value(EGL_BIND_TO_TEXTURE_RGBA) == EGL_DONT_CARE &&
        props.value(EGL_BIND_TO_TEXTURE_RGB) == EGL_DONT_CARE)
#endif
    {
        qWarning() << "QEglContext::chooseConfig(): Could not find a suitable EGL configuration";
        qWarning() << "Requested:" << props.toString();
        qWarning() << "Available:";
        dumpAllConfigs();
    }
    return false;
}

// Create the EGLContext.
bool QEglContext::createContext(QEglContext *shareContext, const QEglProperties *properties)
{
    // We need to select the correct API before calling eglCreateContext().
#ifdef EGL_OPENGL_ES_API
    if (apiType == QEgl::OpenGL)
        eglBindAPI(EGL_OPENGL_ES_API);
#endif
#ifdef EGL_OPENVG_API
    if (apiType == QEgl::OpenVG)
        eglBindAPI(EGL_OPENVG_API);
#endif

    // Create a new context for the configuration.
    QEglProperties contextProps;
    if (properties)
        contextProps = *properties;
#if defined(QT_OPENGL_ES_2)
    if (apiType == QEgl::OpenGL)
        contextProps.setValue(EGL_CONTEXT_CLIENT_VERSION, 2);
#endif
    sharing = false;
    if (shareContext && shareContext->ctx == EGL_NO_CONTEXT)
        shareContext = 0;
    if (shareContext) {
        ctx = eglCreateContext(display(), cfg, shareContext->ctx, contextProps.properties());
        if (ctx == EGL_NO_CONTEXT) {
            qWarning() << "QEglContext::createContext(): Could not share context:" << errorString(eglGetError());
            shareContext = 0;
        } else {
            sharing = true;
        }
    }
    if (ctx == EGL_NO_CONTEXT) {
        ctx = eglCreateContext(display(), cfg, 0, contextProps.properties());
        if (ctx == EGL_NO_CONTEXT) {
            qWarning() << "QEglContext::createContext(): Unable to create EGL context:" << errorString(eglGetError());
            return false;
        }
    }
    return true;
}

// Destroy an EGL surface object.  If it was current on this context
// then call doneCurrent() for it first.
void QEglContext::destroySurface(EGLSurface surface)
{
    if (surface != EGL_NO_SURFACE) {
        if (surface == currentSurface)
            doneCurrent();
        eglDestroySurface(display(), surface);
    }
}

// Destroy the context.  Note: this does not destroy the surface.
void QEglContext::destroyContext()
{
    if (ctx != EGL_NO_CONTEXT && ownsContext)
        eglDestroyContext(display(), ctx);
    ctx = EGL_NO_CONTEXT;
    cfg = 0;
}

bool QEglContext::makeCurrent(EGLSurface surface)
{
    if (ctx == EGL_NO_CONTEXT) {
        qWarning() << "QEglContext::makeCurrent(): Cannot make invalid context current";
        return false;
    }

    // If lazyDoneCurrent() was called on the surface, then we may be able
    // to assume that it is still current within the thread.
    if (surface == currentSurface && currentContext(apiType) == this) {
        current = true;
        return true;
    }

    current = true;
    currentSurface = surface;
    setCurrentContext(apiType, this);

    // Force the right API to be bound before making the context current.
    // The EGL implementation should be able to figure this out from ctx,
    // but some systems require the API to be explicitly set anyway.
#ifdef EGL_OPENGL_ES_API
    if (apiType == QEgl::OpenGL)
        eglBindAPI(EGL_OPENGL_ES_API);
#endif
#ifdef EGL_OPENVG_API
    if (apiType == QEgl::OpenVG)
        eglBindAPI(EGL_OPENVG_API);
#endif

    bool ok = eglMakeCurrent(display(), surface, surface, ctx);
    if (!ok)
        qWarning() << "QEglContext::makeCurrent():" << errorString(eglGetError());
    return ok;
}

bool QEglContext::doneCurrent()
{
    // If the context is invalid, we assume that an error was reported
    // when makeCurrent() was called.
    if (ctx == EGL_NO_CONTEXT)
        return false;

    current = false;
    currentSurface = EGL_NO_SURFACE;
    setCurrentContext(apiType, 0);

    // We need to select the correct API before calling eglMakeCurrent()
    // with EGL_NO_CONTEXT because threads can have both OpenGL and OpenVG
    // contexts active at the same time.
#ifdef EGL_OPENGL_ES_API
    if (apiType == QEgl::OpenGL)
        eglBindAPI(EGL_OPENGL_ES_API);
#endif
#ifdef EGL_OPENVG_API
    if (apiType == QEgl::OpenVG)
        eglBindAPI(EGL_OPENVG_API);
#endif

    bool ok = eglMakeCurrent(display(), EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
    if (!ok)
        qWarning() << "QEglContext::doneCurrent():" << errorString(eglGetError());
    return ok;
}

// Act as though doneCurrent() was called, but keep the context
// and the surface active for the moment.  This allows makeCurrent()
// to skip a call to eglMakeCurrent() if we are using the same
// surface as the last set of painting operations.  We leave the
// currentContext() pointer as-is for now.
bool QEglContext::lazyDoneCurrent()
{
    current = false;
    return true;
}

bool QEglContext::swapBuffers(EGLSurface surface)
{
    if(ctx == EGL_NO_CONTEXT)
        return false;

    bool ok = eglSwapBuffers(display(), surface);
    if (!ok)
        qWarning() << "QEglContext::swapBuffers():" << errorString(eglGetError());
    return ok;
}

// Wait for native rendering operations to complete before starting
// to use OpenGL/OpenVG operations.
void QEglContext::waitNative()
{
#ifdef EGL_CORE_NATIVE_ENGINE
    eglWaitNative(EGL_CORE_NATIVE_ENGINE);
#endif
}

// Wait for client OpenGL/OpenVG operations to complete before
// using native rendering operations.
void QEglContext::waitClient()
{
#ifdef EGL_OPENGL_ES_API
    if (apiType == QEgl::OpenGL) {
        eglBindAPI(EGL_OPENGL_ES_API);
        eglWaitClient();
    }
#else
    if (apiType == QEgl::OpenGL)
        eglWaitGL();
#endif
#ifdef EGL_OPENVG_API
    if (apiType == QEgl::OpenVG) {
        eglBindAPI(EGL_OPENVG_API);
        eglWaitClient();
    }
#endif
}

// Query the value of a configuration attribute.
bool QEglContext::configAttrib(int name, EGLint *value) const
{
    return eglGetConfigAttrib(display(), cfg, name, value);
}

void QEglContext::clearError()
{
    eglGetError();
}

EGLint QEglContext::error()
{
    return eglGetError();
}

// Retrieve all of the properties on "cfg".  If zero, return
// the context's configuration.
QEglProperties QEglContext::configProperties(EGLConfig cfg) const
{
    if (!cfg)
        cfg = config();
    QEglProperties props;
    for (int name = 0x3020; name <= 0x304F; ++name) {
        EGLint value;
        if (name != EGL_NONE && eglGetConfigAttrib(display(), cfg, name, &value))
            props.setValue(name, value);
    }
    eglGetError();  // Clear the error state.
    return props;
}

EGLDisplay QEglContext::display()
{
    if (!QEglContextTracker::displayOpened()) {
        dpy = eglGetDisplay(nativeDisplay());
        QEglContextTracker::setDisplayOpened();
        if (dpy == EGL_NO_DISPLAY) {
            qWarning("QEglContext::display(): Falling back to EGL_DEFAULT_DISPLAY");
            dpy = eglGetDisplay(EGLNativeDisplayType(EGL_DEFAULT_DISPLAY));
        }
        if (dpy == EGL_NO_DISPLAY) {
            qWarning("QEglContext::display(): Can't even open the default display");
            return EGL_NO_DISPLAY;
        }

        if (!eglInitialize(dpy, NULL, NULL)) {
            qWarning() << "QEglContext::display(): Cannot initialize EGL display:" << errorString(eglGetError());
            return EGL_NO_DISPLAY;
        }
    }

    return dpy;
}

#if !defined(Q_WS_X11) && !defined(Q_WS_WINCE) // WinCE & X11 implement this properly
EGLNativeDisplayType QEglContext::nativeDisplay()
{
    return EGL_DEFAULT_DISPLAY;
}
#endif

// Return the error string associated with a specific code.
QString QEglContext::errorString(EGLint code)
{
    static const char * const errors[] = {
        "Success (0x3000)",                 // No tr
        "Not initialized (0x3001)",         // No tr
        "Bad access (0x3002)",              // No tr
        "Bad alloc (0x3003)",               // No tr
        "Bad attribute (0x3004)",           // No tr
        "Bad config (0x3005)",              // No tr
        "Bad context (0x3006)",             // No tr
        "Bad current surface (0x3007)",     // No tr
        "Bad display (0x3008)",             // No tr
        "Bad match (0x3009)",               // No tr
        "Bad native pixmap (0x300A)",       // No tr
        "Bad native window (0x300B)",       // No tr
        "Bad parameter (0x300C)",           // No tr
        "Bad surface (0x300D)",             // No tr
        "Context lost (0x300E)"             // No tr
    };
    if (code >= 0x3000 && code <= 0x300E) {
        return QString::fromLatin1(errors[code - 0x3000]);
    } else {
        return QLatin1String("0x") + QString::number(int(code), 16);
    }
}

// Dump all of the EGL configurations supported by the system.
void QEglContext::dumpAllConfigs()
{
    QEglProperties props;
    EGLint count = 0;
    if (!eglGetConfigs(display(), 0, 0, &count) || count < 1)
        return;
    EGLConfig *configs = new EGLConfig [count];
    eglGetConfigs(display(), configs, count, &count);
    for (EGLint index = 0; index < count; ++index) {
        props = configProperties(configs[index]);
        qWarning() << props.toString();
    }
    delete [] configs;
}

QString QEglContext::extensions()
{
    const char* exts = eglQueryString(QEglContext::display(), EGL_EXTENSIONS);
    return QString(QLatin1String(exts));
}

bool QEglContext::hasExtension(const char* extensionName)
{
    QList<QByteArray> extensions =
        QByteArray(reinterpret_cast<const char *>
            (eglQueryString(QEglContext::display(), EGL_EXTENSIONS))).split(' ');
    return extensions.contains(extensionName);
}

QEglContext *QEglContext::currentContext(QEgl::API api)
{
    if (api == QEgl::OpenGL)
        return currentGLContext;
    else
        return currentVGContext;
}

void QEglContext::setCurrentContext(QEgl::API api, QEglContext *context)
{
    if (api == QEgl::OpenGL)
        currentGLContext = context;
    else
        currentVGContext = context;
}

QT_END_NAMESPACE