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#include "qeglplatformcontext_p.h"

#include "qeglconvenience_p.h"

#include <qpa/qplatformwindow.h>

#include <EGL/egl.h>

static inline void bindApi(const QSurfaceFormat &format)
{
    switch (format.renderableType()) {
    case QSurfaceFormat::OpenVG:
        eglBindAPI(EGL_OPENVG_API);
        break;
#ifdef EGL_VERSION_1_4
#  if !defined(QT_OPENGL_ES_2)
    case QSurfaceFormat::DefaultRenderableType:
#  endif
    case QSurfaceFormat::OpenGL:
        eglBindAPI(EGL_OPENGL_API);
        break;
#endif
    case QSurfaceFormat::OpenGLES:
    default:
        eglBindAPI(EGL_OPENGL_ES_API);
        break;
    }
}

QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, EGLDisplay display,
                                         EGLenum eglApi)
    : m_eglDisplay(display)
    , m_eglConfig(q_configFromGLFormat(display, format))
    , m_swapInterval(-1)
    , m_swapIntervalEnvChecked(false)
    , m_swapIntervalFromEnv(-1)
{
    init(format, share);
    Q_UNUSED(eglApi);
}

QEGLPlatformContext::QEGLPlatformContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share, EGLDisplay display,
                                         EGLConfig config, EGLenum eglApi)
    : m_eglDisplay(display)
    , m_eglConfig(config)
{
    init(format, share);
    Q_UNUSED(eglApi);
}

void QEGLPlatformContext::init(const QSurfaceFormat &format, QPlatformOpenGLContext *share)
{
    m_format = q_glFormatFromConfig(m_eglDisplay, m_eglConfig);
    m_shareContext = share ? static_cast<QEGLPlatformContext *>(share)->m_eglContext : 0;

    QVector<EGLint> contextAttrs;
    contextAttrs.append(EGL_CONTEXT_CLIENT_VERSION);
    contextAttrs.append(format.majorVersion());
    contextAttrs.append(EGL_NONE);

    bindApi(m_format);
    m_eglContext = eglCreateContext(m_eglDisplay, m_eglConfig, m_shareContext, contextAttrs.constData());
    if (m_eglContext == EGL_NO_CONTEXT && m_shareContext != EGL_NO_CONTEXT) {
        m_shareContext = 0;
        m_eglContext = eglCreateContext(m_eglDisplay, m_eglConfig, 0, contextAttrs.constData());
    }
}

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

#ifdef QEGL_EXTRA_DEBUG
    qWarning("QEglContext::makeCurrent: %p\n",this);
#endif
    bindApi(m_format);

    EGLSurface eglSurface = eglSurfaceForPlatformSurface(surface);

    // shortcut: on some GPUs, eglMakeCurrent is not a cheap operation
    if (eglGetCurrentContext() == m_eglContext &&
        eglGetCurrentDisplay() == m_eglDisplay &&
        eglGetCurrentSurface(EGL_READ) == eglSurface &&
        eglGetCurrentSurface(EGL_DRAW) == eglSurface) {
        return true;
    }

    bool ok = eglMakeCurrent(m_eglDisplay, eglSurface, eglSurface, m_eglContext);
    if (!ok)
        qWarning("QEGLPlatformContext::makeCurrent: eglError: %x, this: %p \n", eglGetError(), this);
#ifdef QEGL_EXTRA_DEBUG
    static bool showDebug = true;
    if (showDebug) {
        showDebug = false;
        const char *str = (const char*)glGetString(GL_VENDOR);
        qWarning("Vendor %s\n", str);
        str = (const char*)glGetString(GL_RENDERER);
        qWarning("Renderer %s\n", str);
        str = (const char*)glGetString(GL_VERSION);
        qWarning("Version %s\n", str);

        str = (const char*)glGetString(GL_SHADING_LANGUAGE_VERSION);
        qWarning("Extensions %s\n",str);

        str = (const char*)glGetString(GL_EXTENSIONS);
        qWarning("Extensions %s\n", str);

    }
#endif

    if (ok) {
        if (!m_swapIntervalEnvChecked) {
            m_swapIntervalEnvChecked = true;
            if (qEnvironmentVariableIsSet("QT_QPA_EGL_SWAPINTERVAL")) {
                QByteArray swapIntervalString = qgetenv("QT_QPA_EGL_SWAPINTERVAL");
                bool ok;
                const int swapInterval = swapIntervalString.toInt(&ok);
                if (ok)
                    m_swapIntervalFromEnv = swapInterval;
            }
        }
        const int requestedSwapInterval = m_swapIntervalFromEnv >= 0
            ? m_swapIntervalFromEnv
            : surface->format().swapInterval();
        if (requestedSwapInterval >= 0 && m_swapInterval != requestedSwapInterval) {
            m_swapInterval = requestedSwapInterval;
            eglSwapInterval(eglDisplay(), m_swapInterval);
        }
    }

    return ok;
}

QEGLPlatformContext::~QEGLPlatformContext()
{
#ifdef QEGL_EXTRA_DEBUG
    qWarning("QEglContext::~QEglContext(): %p\n",this);
#endif
    if (m_eglContext != EGL_NO_CONTEXT) {
        eglDestroyContext(m_eglDisplay, m_eglContext);
        m_eglContext = EGL_NO_CONTEXT;
    }
}

void QEGLPlatformContext::doneCurrent()
{
#ifdef QEGL_EXTRA_DEBUG
    qWarning("QEglContext::doneCurrent:%p\n",this);
#endif
    bindApi(m_format);
    bool ok = eglMakeCurrent(m_eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
    if (!ok)
        qWarning("QEGLPlatformContext::doneCurrent(): eglError: %d, this: %p \n", eglGetError(), this);
}

void QEGLPlatformContext::swapBuffers(QPlatformSurface *surface)
{
#ifdef QEGL_EXTRA_DEBUG
    qWarning("QEglContext::swapBuffers:%p\n",this);
#endif
    bindApi(m_format);
    EGLSurface eglSurface = eglSurfaceForPlatformSurface(surface);
    bool ok = eglSwapBuffers(m_eglDisplay, eglSurface);
    if (!ok)
        qWarning("QEGLPlatformContext::swapBuffers(): eglError: %d, this: %p \n", eglGetError(), this);
}

void (*QEGLPlatformContext::getProcAddress(const QByteArray &procName)) ()
{
#ifdef QEGL_EXTRA_DEBUG
    qWarning("QEglContext::getProcAddress%p\n",this);
#endif
    bindApi(m_format);
    return eglGetProcAddress(procName.constData());
}

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

EGLContext QEGLPlatformContext::eglContext() const
{
    return m_eglContext;
}

EGLDisplay QEGLPlatformContext::eglDisplay() const
{
    return m_eglDisplay;
}

EGLConfig QEGLPlatformContext::eglConfig() const
{
    return m_eglConfig;
}