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#include "openglvertexarrayobject_p.h"
#include <Qt3DRender/private/graphicscontext_p.h>
#include <Qt3DRender/private/renderer_p.h>
#include <Qt3DRender/private/nodemanagers_p.h>
#include <Qt3DRender/private/managers_p.h>

QT_BEGIN_NAMESPACE

namespace Qt3DRender {
namespace Render {

OpenGLVertexArrayObject::OpenGLVertexArrayObject()
    : m_ctx(nullptr)
    , m_specified(false)
    , m_supportsVao(false)
{}

void OpenGLVertexArrayObject::bind()
{
    Q_ASSERT(m_ctx);
    if (m_supportsVao) {
        Q_ASSERT(!m_vao.isNull());
        Q_ASSERT(m_vao->isCreated());
        m_vao->bind();
    } else {
        // Unbind any other VAO that may have been bound and not released correctly
        if (m_ctx->m_currentVAO != nullptr && m_ctx->m_currentVAO != this)
            m_ctx->m_currentVAO->release();

        m_ctx->m_currentVAO = this;
        // We need to specify array and vertex attributes
        for (const GraphicsContext::VAOVertexAttribute &attr : qAsConst(m_vertexAttributes))
            m_ctx->enableAttribute(attr);
        if (!m_indexAttribute.isNull())
            m_ctx->bindGLBuffer(m_ctx->m_renderer->nodeManagers()->glBufferManager()->data(m_indexAttribute),
                                GLBuffer::IndexBuffer);
    }
}

void OpenGLVertexArrayObject::release()
{
    Q_ASSERT(m_ctx);
    if (m_supportsVao) {
        Q_ASSERT(!m_vao.isNull());
        Q_ASSERT(m_vao->isCreated());
        m_vao->release();
    } else {
        if (m_ctx->m_currentVAO == this) {
            for (const GraphicsContext::VAOVertexAttribute &attr : qAsConst(m_vertexAttributes))
                m_ctx->disableAttribute(attr);
            m_ctx->m_currentVAO = nullptr;
        }
    }
}

// called from Render thread
void OpenGLVertexArrayObject::create(GraphicsContext *ctx, const VAOIdentifier &key)
{
    QMutexLocker lock(&m_mutex);

    Q_ASSERT(!m_ctx && !m_vao);

    m_ctx = ctx;
    m_supportsVao = m_ctx->supportsVAO();
    if (m_supportsVao) {
        m_vao.reset(new QOpenGLVertexArrayObject());
        m_vao->create();
    }
    m_owners = key;
}

// called from Render thread
void OpenGLVertexArrayObject::destroy()
{
    QMutexLocker locker(&m_mutex);

    Q_ASSERT(m_ctx);
    cleanup();
}

void OpenGLVertexArrayObject::cleanup()
{
    m_vao.reset();
    m_ctx = nullptr;
    m_specified = false;
    m_supportsVao = false;
    m_indexAttribute = GraphicsContext::VAOIndexAttribute();
    m_vertexAttributes.clear();
}

// called from job
bool OpenGLVertexArrayObject::isAbandoned(GeometryManager *geomMgr, ShaderManager *shaderMgr)
{
    QMutexLocker lock(&m_mutex);

    if (!m_ctx)
        return false;

    const bool geometryExists = (geomMgr->data(m_owners.first) != nullptr);
    const bool shaderExists = (shaderMgr->data(m_owners.second) != nullptr);

    return !geometryExists || !shaderExists;
}

void OpenGLVertexArrayObject::saveVertexAttribute(const GraphicsContext::VAOVertexAttribute &attr)
{
    // Remove any vertexAttribute already at location
    for (auto i = m_vertexAttributes.size() - 1; i >= 0; --i) {
        if (m_vertexAttributes.at(i).location == attr.location) {
            m_vertexAttributes.removeAt(i);
            break;
        }
    }
    m_vertexAttributes.push_back(attr);
}


} // namespace Render
} // namespace Qt3DRender

QT_END_NAMESPACE