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#include "qcocoaglcontext.h"
#include "qcocoawindow.h"
#include "qcocoaautoreleasepool.h"
#include <qdebug.h>
#include <QtCore/private/qcore_mac_p.h>
#include <QtPlatformSupport/private/cglconvenience_p.h>

#import <Cocoa/Cocoa.h>

static inline QByteArray getGlString(GLenum param)
{
    if (const GLubyte *s = glGetString(param))
        return QByteArray(reinterpret_cast<const char*>(s));
    return QByteArray();
}

#if !defined(GL_CONTEXT_FLAGS)
#define GL_CONTEXT_FLAGS 0x821E
#endif

#if !defined(GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT)
#define GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT 0x0001
#endif

#if !defined(GL_CONTEXT_PROFILE_MASK)
#define GL_CONTEXT_PROFILE_MASK 0x9126
#endif

#if !defined(GL_CONTEXT_CORE_PROFILE_BIT)
#define GL_CONTEXT_CORE_PROFILE_BIT 0x00000001
#endif

#if !defined(GL_CONTEXT_COMPATIBILITY_PROFILE_BIT)
#define GL_CONTEXT_COMPATIBILITY_PROFILE_BIT 0x00000002
#endif

static void updateFormatFromContext(QSurfaceFormat *format)
{
    Q_ASSERT(format);

    // Update the version, profile, and context bit of the format
    int major = 0, minor = 0;
    QByteArray versionString(getGlString(GL_VERSION));
    if (QPlatformOpenGLContext::parseOpenGLVersion(versionString, major, minor)) {
        format->setMajorVersion(major);
        format->setMinorVersion(minor);
    }

    format->setProfile(QSurfaceFormat::NoProfile);

    Q_ASSERT(format->renderableType() == QSurfaceFormat::OpenGL);
    if (format->version() < qMakePair(3, 0)) {
        format->setOption(QSurfaceFormat::DeprecatedFunctions);
        return;
    }

    // Version 3.0 onwards - check if it includes deprecated functionality
    GLint value = 0;
    glGetIntegerv(GL_CONTEXT_FLAGS, &value);
    if (!(value & GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT))
        format->setOption(QSurfaceFormat::DeprecatedFunctions);

    // Debug context option not supported on OS X

    if (format->version() < qMakePair(3, 2))
        return;

    // Version 3.2 and newer have a profile
    value = 0;
    glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &value);

    if (value & GL_CONTEXT_CORE_PROFILE_BIT)
        format->setProfile(QSurfaceFormat::CoreProfile);
    else if (value & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT)
        format->setProfile(QSurfaceFormat::CompatibilityProfile);
}

QCocoaGLContext::QCocoaGLContext(const QSurfaceFormat &format, QPlatformOpenGLContext *share)
    : m_context(nil),
      m_shareContext(nil),
      m_format(format)
{
    // we only support OpenGL contexts under Cocoa
    if (m_format.renderableType() == QSurfaceFormat::DefaultRenderableType)
        m_format.setRenderableType(QSurfaceFormat::OpenGL);
    if (m_format.renderableType() != QSurfaceFormat::OpenGL)
        return;

    QCocoaAutoReleasePool pool; // For the SG Canvas render thread

    NSOpenGLPixelFormat *pixelFormat = static_cast <NSOpenGLPixelFormat *>(qcgl_createNSOpenGLPixelFormat(m_format));
    m_shareContext = share ? static_cast<QCocoaGLContext *>(share)->nsOpenGLContext() : nil;

    m_context = [NSOpenGLContext alloc];
    [m_context initWithFormat:pixelFormat shareContext:m_shareContext];

    if (!m_context && m_shareContext) {
        // try without shared context
        m_shareContext = nil;
        [m_context initWithFormat:pixelFormat shareContext:nil];
    }

    [pixelFormat release];

    const GLint interval = format.swapInterval() >= 0 ? format.swapInterval() : 1;
    [m_context setValues:&interval forParameter:NSOpenGLCPSwapInterval];

    if (format.alphaBufferSize() > 0) {
        int zeroOpacity = 0;
        [m_context setValues:&zeroOpacity forParameter:NSOpenGLCPSurfaceOpacity];
    }

    updateSurfaceFormat();
}

QCocoaGLContext::~QCocoaGLContext()
{
    [m_context release];
}

// Match up with createNSOpenGLPixelFormat!
QSurfaceFormat QCocoaGLContext::format() const
{
    return m_format;
}

void QCocoaGLContext::windowWasHidden()
{
    // If the window is hidden, we need to unset the m_currentWindow
    // variable so that succeeding makeCurrent's will not abort prematurely
    // because of the optimization in setActiveWindow.
    // Doing a full doneCurrent here is not preferable, because the GL context
    // might be rendering in a different thread at this time.
    m_currentWindow.clear();
}

void QCocoaGLContext::swapBuffers(QPlatformSurface *surface)
{
    QWindow *window = static_cast<QCocoaWindow *>(surface)->window();
    setActiveWindow(window);

    [m_context flushBuffer];
}

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

    QCocoaAutoReleasePool pool;

    QWindow *window = static_cast<QCocoaWindow *>(surface)->window();
    setActiveWindow(window);

    if (![m_context view])
        return false;
    [m_context makeCurrentContext];
    update();
    return true;
}

void QCocoaGLContext::setActiveWindow(QWindow *window)
{
    if (window == m_currentWindow.data())
        return;

    if (m_currentWindow && m_currentWindow.data()->handle())
        static_cast<QCocoaWindow *>(m_currentWindow.data()->handle())->setCurrentContext(0);

    Q_ASSERT(window->handle());

    m_currentWindow = window;

    QCocoaWindow *cocoaWindow = static_cast<QCocoaWindow *>(window->handle());
    cocoaWindow->setCurrentContext(this);

    [(QNSView *) cocoaWindow->contentView() setQCocoaGLContext:this];
}

void QCocoaGLContext::updateSurfaceFormat()
{
    // At present it is impossible to turn an option off on a QSurfaceFormat (see
    // https://codereview.qt-project.org/#change,70599). So we have to populate
    // the actual surface format from scratch
    QSurfaceFormat requestedFormat = m_format;
    m_format = QSurfaceFormat();
    m_format.setRenderableType(QSurfaceFormat::OpenGL);

    // CoreGL doesn't require a drawable to make the context current
    CGLContextObj oldContext = CGLGetCurrentContext();
    CGLContextObj ctx = static_cast<CGLContextObj>([m_context CGLContextObj]);
    CGLSetCurrentContext(ctx);

    // Get the data that OpenGL provides
    updateFormatFromContext(&m_format);

    // Get the data contained within the pixel format
    CGLPixelFormatObj cglPixelFormat = static_cast<CGLPixelFormatObj>(CGLGetPixelFormat(ctx));
    NSOpenGLPixelFormat *pixelFormat = [[NSOpenGLPixelFormat alloc] initWithCGLPixelFormatObj:cglPixelFormat];

    int colorSize = -1;
    [pixelFormat getValues:&colorSize forAttribute:NSOpenGLPFAColorSize forVirtualScreen:0];
    if (colorSize > 0) {
        // This seems to return the total color buffer depth, including alpha
        m_format.setRedBufferSize(colorSize / 4);
        m_format.setGreenBufferSize(colorSize / 4);
        m_format.setBlueBufferSize(colorSize / 4);
    }

    // The pixel format always seems to return 8 for alpha. However, the framebuffer only
    // seems to have alpha enabled if we requested it explicitly. I can't find any other
    // attribute to check explicitly for this so we use our best guess for alpha.
    int alphaSize = -1;
    [pixelFormat getValues:&alphaSize forAttribute:NSOpenGLPFAAlphaSize forVirtualScreen:0];
    if (alphaSize > 0 && requestedFormat.alphaBufferSize() > 0)
        m_format.setAlphaBufferSize(alphaSize);

    int depthSize = -1;
    [pixelFormat getValues:&depthSize forAttribute:NSOpenGLPFADepthSize forVirtualScreen:0];
    if (depthSize > 0)
        m_format.setDepthBufferSize(depthSize);

    int stencilSize = -1;
    [pixelFormat getValues:&stencilSize forAttribute:NSOpenGLPFAStencilSize forVirtualScreen:0];
    if (stencilSize > 0)
        m_format.setStencilBufferSize(stencilSize);

    int samples = -1;
    [pixelFormat getValues:&samples forAttribute:NSOpenGLPFASamples forVirtualScreen:0];
    if (samples > 0)
        m_format.setSamples(samples);

    int doubleBuffered = -1;
    [pixelFormat getValues:&doubleBuffered forAttribute:NSOpenGLPFADoubleBuffer forVirtualScreen:0];
    m_format.setSwapBehavior(doubleBuffered == 1 ? QSurfaceFormat::DoubleBuffer : QSurfaceFormat::SingleBuffer);

    int steroBuffers = -1;
    [pixelFormat getValues:&steroBuffers forAttribute:NSOpenGLPFAStereo forVirtualScreen:0];
    if (steroBuffers == 1)
        m_format.setOption(QSurfaceFormat::StereoBuffers);

    [pixelFormat release];

    // Restore the original context
    CGLSetCurrentContext(oldContext);
}

void QCocoaGLContext::doneCurrent()
{
    if (m_currentWindow && m_currentWindow.data()->handle())
        static_cast<QCocoaWindow *>(m_currentWindow.data()->handle())->setCurrentContext(0);

    m_currentWindow.clear();

    [NSOpenGLContext clearCurrentContext];
}

void (*QCocoaGLContext::getProcAddress(const QByteArray &procName))()
{
    return qcgl_getProcAddress(procName);
}

void QCocoaGLContext::update()
{
    [m_context update];
}

NSOpenGLPixelFormat *QCocoaGLContext::createNSOpenGLPixelFormat(const QSurfaceFormat &format)
{
    return static_cast<NSOpenGLPixelFormat *>(qcgl_createNSOpenGLPixelFormat(format));
}

NSOpenGLContext *QCocoaGLContext::nsOpenGLContext() const
{
    return m_context;
}

bool QCocoaGLContext::isValid() const
{
    return m_context != nil;
}

bool QCocoaGLContext::isSharing() const
{
    return m_shareContext != nil;
}