// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qsgdefaultpainternode_p.h"

#include <QtQuick/private/qquickpainteditem_p.h>

#include <QtQuick/private/qsgdefaultrendercontext_p.h>
#include <QtQuick/private/qsgcontext_p.h>
#include <qmath.h>
#include <qpainter.h>

#if QT_CONFIG(opengl)
#include <private/qopenglextensions_p.h>
#include <rhi/qrhi.h>
#endif

QT_BEGIN_NAMESPACE

#define QT_MINIMUM_DYNAMIC_FBO_SIZE 64U

QSGPainterTexture::QSGPainterTexture()
    : QSGPlainTexture(*(new QSGPlainTexturePrivate(this)))
{
    m_retain_image = true;
}

void QSGPainterTexture::commitTextureOperations(QRhi *rhi, QRhiResourceUpdateBatch *resourceUpdates)
{
    if (!m_dirty_rect.isNull()) {
        setImage(m_image);
        m_dirty_rect = QRect();
    }
    QSGPlainTexture::commitTextureOperations(rhi, resourceUpdates);
}

QSGDefaultPainterNode::QSGDefaultPainterNode(QQuickPaintedItem *item)
    : QSGPainterNode()
    , m_preferredRenderTarget(QQuickPaintedItem::Image)
    , m_actualRenderTarget(QQuickPaintedItem::Image)
    , m_item(item)
    , m_geometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4)
    , m_texture(nullptr)
#if QT_CONFIG(opengl)
    , m_fbo(nullptr)
    , m_multisampledFbo(nullptr)
    , m_gl_device(nullptr)
    , m_wrapperTexture(nullptr)
#endif
    , m_fillColor(Qt::transparent)
    , m_contentsScale(1.0)
    , m_dirtyContents(false)
    , m_opaquePainting(false)
    , m_linear_filtering(false)
    , m_mipmapping(false)
    , m_smoothPainting(false)
#if QT_CONFIG(opengl)
    , m_extensionsChecked(false)
    , m_multisamplingSupported(false)
#endif
    , m_fastFBOResizing(false)
    , m_dirtyGeometry(false)
    , m_dirtyRenderTarget(false)
    , m_dirtyTexture(false)
{
    m_context = static_cast<QSGDefaultRenderContext *>(static_cast<QQuickPaintedItemPrivate *>(QObjectPrivate::get(item))->sceneGraphRenderContext());

    setMaterial(&m_materialO);
    setOpaqueMaterial(&m_material);
    setGeometry(&m_geometry);

#ifdef QSG_RUNTIME_DESCRIPTION
    qsgnode_set_description(this, QString::fromLatin1("QQuickPaintedItem(%1):%2").arg(QString::fromLatin1(item->metaObject()->className())).arg(item->objectName()));
#endif
}

QSGDefaultPainterNode::~QSGDefaultPainterNode()
{
    delete m_texture;

#if QT_CONFIG(opengl)
    delete m_wrapperTexture;
    delete m_fbo;
    delete m_multisampledFbo;
    delete m_gl_device;
#endif
}

void QSGDefaultPainterNode::paint()
{
    QRect dirtyRect = m_dirtyRect.isNull() ? QRect(0, 0, m_size.width(), m_size.height()) : m_dirtyRect;

    QPainter painter;
#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2 && m_actualRenderTarget != QQuickPaintedItem::Image) {
        if (!m_gl_device) {
            m_gl_device = new QOpenGLPaintDevice(m_fboSize);
            m_gl_device->setPaintFlipped(true);
        }

        if (m_multisampledFbo)
            m_multisampledFbo->bind();
        else
            m_fbo->bind();

        painter.begin(m_gl_device);
    } else
#endif
    {
        Q_ASSERT(m_actualRenderTarget == QQuickPaintedItem::Image);
        if (m_image.isNull())
            return;
        // We are not reusing the reference to the image the m_texture, so unset it to avoid detach.
        m_texture->setImage(QImage());
        painter.begin(&m_image);
    }

    if (m_smoothPainting) {
        painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
    }

    QRect clipRect;
    QRect dirtyTextureRect;

    if (m_contentsScale == 1) {
        qreal scaleX = m_textureSize.width() / (qreal) m_size.width();
        qreal scaleY = m_textureSize.height() / (qreal) m_size.height();
        painter.scale(scaleX, scaleY);
        clipRect = dirtyRect;
        dirtyTextureRect = QRectF(dirtyRect.x() * scaleX,
                                  dirtyRect.y() * scaleY,
                                  dirtyRect.width() * scaleX,
                                  dirtyRect.height() * scaleY).toAlignedRect();
    } else {
        painter.scale(m_contentsScale, m_contentsScale);
        QRect sclip(qFloor(dirtyRect.x()/m_contentsScale),
                    qFloor(dirtyRect.y()/m_contentsScale),
                    qCeil(dirtyRect.width()/m_contentsScale+dirtyRect.x()/m_contentsScale-qFloor(dirtyRect.x()/m_contentsScale)),
                    qCeil(dirtyRect.height()/m_contentsScale+dirtyRect.y()/m_contentsScale-qFloor(dirtyRect.y()/m_contentsScale)));
        clipRect = sclip;
        dirtyTextureRect = dirtyRect;
    }

    // only clip if we were originally updating only a subrect
    if (!m_dirtyRect.isNull()) {
        painter.setClipRect(clipRect);
    }

    painter.setCompositionMode(QPainter::CompositionMode_Source);
    if (m_fillColor.isValid())
        painter.fillRect(clipRect, m_fillColor);
    painter.setCompositionMode(QPainter::CompositionMode_SourceOver);

    m_item->paint(&painter);
    painter.end();

#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2 && m_actualRenderTarget != QQuickPaintedItem::Image) {
        if (m_multisampledFbo) {
            QOpenGLFramebufferObject::blitFramebuffer(m_fbo, dirtyTextureRect, m_multisampledFbo, dirtyTextureRect);
            m_multisampledFbo->release();
        } else if (m_fbo) {
            m_fbo->release();
        }
    } else
#endif
    {
        m_texture->setImage(m_image);
        m_texture->setDirtyRect(dirtyTextureRect);
    }

    m_dirtyRect = QRect();
}

void QSGDefaultPainterNode::update()
{
    if (m_dirtyRenderTarget)
        updateRenderTarget();
    if (m_dirtyGeometry)
        updateGeometry();
    if (m_dirtyTexture)
        updateTexture();

    if (m_dirtyContents)
        paint();

    m_dirtyGeometry = false;
    m_dirtyRenderTarget = false;
    m_dirtyTexture = false;
    m_dirtyContents = false;
}

void QSGDefaultPainterNode::updateTexture()
{
    m_texture->setHasAlphaChannel(!m_opaquePainting);
    m_material.setTexture(m_texture);
    m_materialO.setTexture(m_texture);

    markDirty(DirtyMaterial);
}

void QSGDefaultPainterNode::updateGeometry()
{
    QRectF source;
#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2 && m_actualRenderTarget != QQuickPaintedItem::Image) {
        source = QRectF(0, 0, qreal(m_textureSize.width()) / m_fboSize.width(), qreal(m_textureSize.height()) / m_fboSize.height());
    } else
#endif
    {
        source = QRectF(0, 0, 1, 1);
    }
    QRectF dest(0, 0, m_size.width(), m_size.height());
    if (m_actualRenderTarget == QQuickPaintedItem::InvertedYFramebufferObject)
        dest = QRectF(QPointF(0, m_size.height()), QPointF(m_size.width(), 0));
    QSGGeometry::updateTexturedRectGeometry(&m_geometry,
                                            dest,
                                            source);
    markDirty(DirtyGeometry);
}

void QSGDefaultPainterNode::updateRenderTarget()
{
    m_dirtyContents = true;

#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2) {
        if (!m_extensionsChecked) {
            QOpenGLExtensions *e = static_cast<QOpenGLExtensions *>(QOpenGLContext::currentContext()->functions());
            m_multisamplingSupported = e->hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)
                                       && e->hasOpenGLExtension(QOpenGLExtensions::FramebufferBlit);
            m_extensionsChecked = true;
        }
        QQuickPaintedItem::RenderTarget oldTarget = m_actualRenderTarget;
        if (m_preferredRenderTarget == QQuickPaintedItem::Image) {
            m_actualRenderTarget = QQuickPaintedItem::Image;
        } else {
            // Image is the only option when there is no multisample framebuffer
            // support and smooth painting is wanted, and when using the RHI. The
            // latter may change in the future.
            if (!m_multisamplingSupported && m_smoothPainting)
                m_actualRenderTarget = QQuickPaintedItem::Image;
            else
                m_actualRenderTarget = m_preferredRenderTarget;
        }
        if (oldTarget != m_actualRenderTarget) {
            m_image = QImage();
            delete m_fbo;
            delete m_multisampledFbo;
            delete m_gl_device;
            m_fbo = m_multisampledFbo = nullptr;
            m_gl_device = nullptr;
        }

        if (m_actualRenderTarget == QQuickPaintedItem::FramebufferObject
            || m_actualRenderTarget == QQuickPaintedItem::InvertedYFramebufferObject)
        {
            const QOpenGLContext *ctx = static_cast<const QRhiGles2NativeHandles *>(m_context->rhi()->nativeHandles())->context;
            if (m_fbo && !m_dirtyGeometry && (!ctx->format().samples() || !m_multisamplingSupported))
                return;

            if (m_fboSize.isEmpty())
                updateFBOSize();

            delete m_fbo;
            delete m_multisampledFbo;
            m_fbo = m_multisampledFbo = nullptr;
            if (m_gl_device)
                m_gl_device->setSize(m_fboSize);

            if (m_smoothPainting && ctx->format().samples() && m_multisamplingSupported) {
                QOpenGLFramebufferObjectFormat msaaFormat;
                msaaFormat.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
                msaaFormat.setSamples(8);
                m_multisampledFbo = new QOpenGLFramebufferObject(m_fboSize, msaaFormat);
                QOpenGLFramebufferObjectFormat format;
                format.setAttachment(QOpenGLFramebufferObject::NoAttachment);
                m_fbo = new QOpenGLFramebufferObject(m_fboSize, format);
            } else {
                QOpenGLFramebufferObjectFormat format;
                format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
                m_fbo = new QOpenGLFramebufferObject(m_fboSize, format);
            }
        } else {
            if (!m_image.isNull() && !m_dirtyGeometry)
                return;

            m_image = QImage(m_textureSize, QImage::Format_RGBA8888_Premultiplied);
            m_image.fill(Qt::transparent);
        }

        QSGPainterTexture *texture = new QSGPainterTexture;
        if (m_actualRenderTarget == QQuickPaintedItem::Image) {
            texture->setOwnsTexture(true);
            texture->setTextureSize(m_textureSize);
        } else {
            if (!m_wrapperTexture)
                m_wrapperTexture = m_context->rhi()->newTexture(QRhiTexture::RGBA8, m_fboSize);
            m_wrapperTexture->createFrom({ m_fbo->texture(), 0 });
            texture->setTexture(m_wrapperTexture);
            texture->setOwnsTexture(false);
            texture->setTextureSize(m_fboSize);
        }

        if (m_texture)
            delete m_texture;

        m_texture = texture;
    } else
#endif
    {
        m_actualRenderTarget = QQuickPaintedItem::Image;
        if (!m_image.isNull() && !m_dirtyGeometry)
            return;

        m_image = QImage(m_textureSize, QImage::Format_RGBA8888_Premultiplied);
        m_image.fill(Qt::transparent);

        if (!m_texture) {
            m_texture = new QSGPainterTexture;
            m_texture->setOwnsTexture(true);
        }
        m_texture->setTextureSize(m_textureSize);
    }
}

#if QT_CONFIG(opengl)
void QSGDefaultPainterNode::updateFBOSize()
{
    int fboWidth;
    int fboHeight;
    if (m_fastFBOResizing) {
        fboWidth = qMax(QT_MINIMUM_DYNAMIC_FBO_SIZE, qNextPowerOfTwo(m_textureSize.width() - 1));
        fboHeight = qMax(QT_MINIMUM_DYNAMIC_FBO_SIZE, qNextPowerOfTwo(m_textureSize.height() - 1));
    } else {
        QSize minimumFBOSize = m_context->sceneGraphContext()->minimumFBOSize();
        fboWidth = qMax(minimumFBOSize.width(), m_textureSize.width());
        fboHeight = qMax(minimumFBOSize.height(), m_textureSize.height());
    }
    m_fboSize = QSize(fboWidth, fboHeight);
}
#endif

void QSGDefaultPainterNode::setPreferredRenderTarget(QQuickPaintedItem::RenderTarget target)
{
    if (m_preferredRenderTarget == target)
        return;

    m_preferredRenderTarget = target;

    m_dirtyRenderTarget = true;
    m_dirtyGeometry = true;
    m_dirtyTexture = true;
}

void QSGDefaultPainterNode::setSize(const QSize &size)
{
    if (size == m_size)
        return;

    m_size = size;
    m_dirtyGeometry = true;
}

void QSGDefaultPainterNode::setTextureSize(const QSize &size)
{
    if (size == m_textureSize)
        return;

    m_textureSize = size;

#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2) {
        updateFBOSize();
        if (m_fbo)
            m_dirtyRenderTarget = m_fbo->size() != m_fboSize || m_dirtyRenderTarget;
        else
            m_dirtyRenderTarget = true;
    } else
#endif
    {
        m_dirtyRenderTarget = true;
    }

    m_dirtyGeometry = true;
    m_dirtyTexture = true;
}

void QSGDefaultPainterNode::setDirty(const QRect &dirtyRect)
{
    m_dirtyContents = true;
    m_dirtyRect = dirtyRect;

    if (m_mipmapping)
        m_dirtyTexture = true;

    markDirty(DirtyMaterial);
}

void QSGDefaultPainterNode::setOpaquePainting(bool opaque)
{
    if (opaque == m_opaquePainting)
        return;

    m_opaquePainting = opaque;
    m_dirtyTexture = true;
}

void QSGDefaultPainterNode::setLinearFiltering(bool linearFiltering)
{
    if (linearFiltering == m_linear_filtering)
        return;

    m_linear_filtering = linearFiltering;

    m_material.setFiltering(linearFiltering ? QSGTexture::Linear : QSGTexture::Nearest);
    m_materialO.setFiltering(linearFiltering ? QSGTexture::Linear : QSGTexture::Nearest);
    markDirty(DirtyMaterial);
}

void QSGDefaultPainterNode::setMipmapping(bool mipmapping)
{
    if (mipmapping == m_mipmapping)
        return;

    m_mipmapping = mipmapping;
    m_material.setMipmapFiltering(mipmapping ? QSGTexture::Linear : QSGTexture::None);
    m_materialO.setMipmapFiltering(mipmapping ? QSGTexture::Linear : QSGTexture::None);
    m_dirtyTexture = true;
}

void QSGDefaultPainterNode::setSmoothPainting(bool s)
{
    if (s == m_smoothPainting)
        return;

    m_smoothPainting = s;
    m_dirtyRenderTarget = true;
}

void QSGDefaultPainterNode::setFillColor(const QColor &c)
{
    if (c == m_fillColor)
        return;

    m_fillColor = c;
    markDirty(DirtyMaterial);
}

void QSGDefaultPainterNode::setContentsScale(qreal s)
{
    if (s == m_contentsScale)
        return;

    m_contentsScale = s;
    markDirty(DirtyMaterial);
}

void QSGDefaultPainterNode::setFastFBOResizing(bool fastResizing)
{
    if (m_fastFBOResizing == fastResizing)
        return;

    m_fastFBOResizing = fastResizing;

#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2) {
        updateFBOSize();
        if ((m_preferredRenderTarget == QQuickPaintedItem::FramebufferObject
            || m_preferredRenderTarget == QQuickPaintedItem::InvertedYFramebufferObject)
                && (!m_fbo || (m_fbo && m_fbo->size() != m_fboSize))) {
            m_dirtyRenderTarget = true;
            m_dirtyGeometry = true;
            m_dirtyTexture = true;
        }
    }
#endif
}

QImage QSGDefaultPainterNode::toImage() const
{
#if QT_CONFIG(opengl)
    if (m_context->rhi()->backend() == QRhi::OpenGLES2 && m_actualRenderTarget != QQuickPaintedItem::Image) {
        Q_ASSERT(m_fbo);
        return m_fbo->toImage();
    } else
#endif
    {
        Q_ASSERT(m_actualRenderTarget == QQuickPaintedItem::Image);
        return m_image;
    }
}

QT_END_NAMESPACE
