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#include "qsgdepthstencilbuffer_p.h"

QT_BEGIN_NAMESPACE

QSGDepthStencilBuffer::QSGDepthStencilBuffer(QOpenGLContext *context, const Format &format)
    : m_functions(context)
    , m_manager(nullptr)
    , m_format(format)
    , m_depthBuffer(0)
    , m_stencilBuffer(0)
{
    // 'm_manager' is set by QSGDepthStencilBufferManager::insertBuffer().
}

QSGDepthStencilBuffer::~QSGDepthStencilBuffer()
{
    if (m_manager)
        m_manager->m_buffers.remove(m_format);
}

#ifndef GL_DEPTH_STENCIL_ATTACHMENT
#define GL_DEPTH_STENCIL_ATTACHMENT 0x821A
#endif

void QSGDepthStencilBuffer::attach()
{
#ifndef Q_OS_WASM
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                          GL_RENDERBUFFER, m_depthBuffer);
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
                                          GL_RENDERBUFFER, m_stencilBuffer);
#else
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                          GL_RENDERBUFFER, m_stencilBuffer);
#endif
}

void QSGDepthStencilBuffer::detach()
{
#ifndef Q_OS_WASM
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                          GL_RENDERBUFFER, 0);
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
                                          GL_RENDERBUFFER, 0);
#else
    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                          GL_RENDERBUFFER, 0);
#endif
}

#ifndef GL_DEPTH24_STENCIL8_OES
#define GL_DEPTH24_STENCIL8_OES 0x88F0
#endif

#ifndef GL_DEPTH_COMPONENT24_OES
#define GL_DEPTH_COMPONENT24_OES 0x81A6
#endif

#ifndef GL_DEPTH_STENCIL
#define GL_DEPTH_STENCIL 0x84F9
#endif

QSGDefaultDepthStencilBuffer::QSGDefaultDepthStencilBuffer(QOpenGLContext *context, const Format &format)
    : QSGDepthStencilBuffer(context, format)
{
    const GLsizei width = format.size.width();
    const GLsizei height = format.size.height();

#ifndef Q_OS_WASM
    if (format.attachments == (DepthAttachment | StencilAttachment)
            && m_functions.hasOpenGLExtension(QOpenGLExtensions::PackedDepthStencil))
    {
        m_functions.glGenRenderbuffers(1, &m_depthBuffer);
        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
#if defined(QT_OPENGL_ES_2)
            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
                GL_DEPTH24_STENCIL8_OES, width, height);
#else
            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
                GL_DEPTH24_STENCIL8, width, height);
#endif
        } else {
#if defined(QT_OPENGL_ES_2)
            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, width, height);
#else
            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
#endif
        }
        m_stencilBuffer = m_depthBuffer;
    }
    if (!m_depthBuffer && (format.attachments & DepthAttachment)) {
        m_functions.glGenRenderbuffers(1, &m_depthBuffer);
        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
        GLenum internalFormat = GL_DEPTH_COMPONENT;
        if (context->isOpenGLES())
            internalFormat = m_functions.hasOpenGLExtension(QOpenGLExtensions::Depth24)
                ? GL_DEPTH_COMPONENT24_OES : GL_DEPTH_COMPONENT16;
        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
                internalFormat, width, height);
        } else {
            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, internalFormat, width, height);
        }
    }
    if (!m_stencilBuffer && (format.attachments & StencilAttachment)) {
        m_functions.glGenRenderbuffers(1, &m_stencilBuffer);
        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_stencilBuffer);
#ifdef QT_OPENGL_ES
        const GLenum internalFormat = GL_STENCIL_INDEX8;
#else
        const GLenum internalFormat = context->isOpenGLES() ? GL_STENCIL_INDEX8 : GL_STENCIL_INDEX;
#endif
        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
                internalFormat, width, height);
        } else {
            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, internalFormat, width, height);
        }
    }
#else
    m_functions.glGenRenderbuffers(1, &m_depthBuffer);
    m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
    m_functions.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_STENCIL, width, height);
    m_stencilBuffer = m_depthBuffer;
#endif
}

QSGDefaultDepthStencilBuffer::~QSGDefaultDepthStencilBuffer()
{
    free();
}

void QSGDefaultDepthStencilBuffer::free()
{
    if (m_depthBuffer)
        m_functions.glDeleteRenderbuffers(1, &m_depthBuffer);
    if (m_stencilBuffer && m_stencilBuffer != m_depthBuffer)
        m_functions.glDeleteRenderbuffers(1, &m_stencilBuffer);
    m_depthBuffer = m_stencilBuffer = 0;
}


QSGDepthStencilBufferManager::~QSGDepthStencilBufferManager()
{
    for (Hash::const_iterator it = m_buffers.constBegin(), cend = m_buffers.constEnd(); it != cend; ++it) {
        QSharedPointer<QSGDepthStencilBuffer> buffer = it.value().toStrongRef();
        Q_ASSERT_X(buffer, "~QSGDepthStencilBufferManager",
                   "~QSGDepthStencilBuffer is supposed to unregister from the manager");
        buffer->free();
        buffer->m_manager = nullptr;
    }
}

QSharedPointer<QSGDepthStencilBuffer> QSGDepthStencilBufferManager::bufferForFormat(const QSGDepthStencilBuffer::Format &fmt)
{
    Hash::const_iterator it = m_buffers.constFind(fmt);
    if (it != m_buffers.constEnd())
        return it.value().toStrongRef();
    return QSharedPointer<QSGDepthStencilBuffer>();
}

void QSGDepthStencilBufferManager::insertBuffer(const QSharedPointer<QSGDepthStencilBuffer> &buffer)
{
    Q_ASSERT(buffer->m_manager == nullptr);
    Q_ASSERT(!m_buffers.contains(buffer->m_format));
    buffer->m_manager = this;
    m_buffers.insert(buffer->m_format, buffer.toWeakRef());
}

uint qHash(const QSGDepthStencilBuffer::Format &format)
{
    return qHash(qMakePair(format.size.width(), format.size.height()))
            ^ (uint(format.samples) << 12) ^ (uint(format.attachments) << 28);
}

QT_END_NAMESPACE