/****************************************************************************
**
** Copyright (C) 2008-2012 NVIDIA Corporation.
** Copyright (C) 2019 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Quick 3D.
**
** $QT_BEGIN_LICENSE:GPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/


#include "qssgrendernode_p.h"

#include <QtQuick3DUtils/private/qssgutils_p.h>

#include <QtQuick3DRuntimeRender/private/qssgrendermodel_p.h>

#include <QtQuick3DRuntimeRender/private/qssgrenderbuffermanager_p.h>

QT_BEGIN_NAMESPACE

QSSGRenderNode::QSSGRenderNode()
    : QSSGRenderNode(Type::Node)
{

}

QSSGRenderNode::QSSGRenderNode(Type type)
    : QSSGRenderGraphObject(type) {}

// Sets this object dirty and walks down the graph setting all
// children who are not dirty to be dirty.
void QSSGRenderNode::markDirty(TransformDirtyFlag inTransformDirty)
{
    if (!flags.testFlag(Flag::TransformDirty))
        flags.setFlag(Flag::TransformDirty, inTransformDirty != TransformDirtyFlag::TransformNotDirty);
    if (!flags.testFlag(Flag::Dirty)) {
        flags.setFlag(Flag::Dirty, true);
        for (auto &cld : children)
            cld.markDirty(inTransformDirty);
    }
}

// Calculate global transform and opacity
// Walks up the graph ensure all parents are not dirty so they have
// valid global transforms.

bool QSSGRenderNode::calculateGlobalVariables()
{
    bool retval = flags.testFlag(Flag::Dirty);
    if (retval) {
        flags.setFlag(Flag::Dirty, false);
        calculateLocalTransform();
        globalOpacity = localOpacity;
        if (parent) {
            // Layer transforms do not flow down but affect the final layer's rendered
            // representation.
            retval = parent->calculateGlobalVariables() || retval;
            if (parent->type != QSSGRenderGraphObject::Type::Layer) {
                globalOpacity *= parent->globalOpacity;
                if (!flags.testFlag(Flag::IgnoreParentTransform))
                    globalTransform = parent->globalTransform * localTransform;
                else
                    globalTransform = localTransform;
            } else {
                globalTransform = localTransform;
            }
            if (this == instanceRoot) {
                globalInstanceTransform = parent->globalTransform;
                localInstanceTransform = localTransform;
            } else if (instanceRoot) {
                globalInstanceTransform = instanceRoot->globalInstanceTransform;
                //### technically O(n^2) -- we could cache localInstanceTransform if every node in the
                // tree is guaranteed to have the same instance root. That would require an API change.
                localInstanceTransform = localTransform;
                auto *p = parent;
                while (p) {
                    if (p == instanceRoot) {
                        localInstanceTransform = p->localInstanceTransform * localInstanceTransform;
                        break;
                    }
                    localInstanceTransform = p->localTransform * localInstanceTransform;
                    p = p->parent;
                }
            } else {
                // By default, we do magic: translation is applied to the global instance transform,
                // while scale/rotation is local

                localInstanceTransform = localTransform;
                auto &localInstanceMatrix =  *reinterpret_cast<float (*)[4][4]>(localInstanceTransform.data());
                QVector3D localPos{localInstanceMatrix[3][0], localInstanceMatrix[3][1], localInstanceMatrix[3][2]};
                localInstanceMatrix[3][0] = 0;
                localInstanceMatrix[3][1] = 0;
                localInstanceMatrix[3][2] = 0;
                globalInstanceTransform = parent->globalTransform;
                globalInstanceTransform.translate(localPos);
            }

            flags.setFlag(Flag::GloballyActive, (flags.testFlag(Flag::Active) && parent->flags.testFlag(Flag::GloballyActive)));
            flags.setFlag(Flag::GloballyPickable, (flags.testFlag(Flag::LocallyPickable) || parent->flags.testFlag(Flag::GloballyPickable)));
        } else {
            globalTransform = localTransform;
            flags.setFlag(Flag::GloballyActive, flags.testFlag(Flag::Active));
            flags.setFlag(Flag::GloballyPickable, flags.testFlag(Flag::LocallyPickable));
            localInstanceTransform = localTransform;
            globalInstanceTransform = {};
        }
    }
    // We always clear dirty in a reasonable manner but if we aren't active
    // there is no reason to tell the universe if we are dirty or not.
    return retval && flags.testFlag(Flag::Active);
}

void QSSGRenderNode::calculateRotationMatrix(QMatrix4x4 &outMatrix) const
{
    outMatrix = QMatrix4x4(rotation.toRotationMatrix());
}

void QSSGRenderNode::calculateLocalTransform()
{
    if (flags.testFlag(Flag::TransformDirty)) {
        flags.setFlag(Flag::TransformDirty, false);
        localTransform = QMatrix4x4();
        globalTransform = localTransform;
        float *writePtr = localTransform.data();
        QVector3D theScaledPivot(-pivot[0] * scale[0], -pivot[1] * scale[1], -pivot[2] * scale[2]);
        localTransform(0, 0) = scale[0];
        localTransform(1, 1) = scale[1];
        localTransform(2, 2) = scale[2];

        writePtr[12] = theScaledPivot[0];
        writePtr[13] = theScaledPivot[1];
        writePtr[14] = theScaledPivot[2];

        QMatrix4x4 theRotationTransform;
        calculateRotationMatrix(theRotationTransform);
        // may need column conversion in here somewhere.
        localTransform = theRotationTransform * localTransform;

        writePtr[12] += position[0];
        writePtr[13] += position[1];
        writePtr[14] += position[2];
    }
}

void QSSGRenderNode::setLocalTransformFromMatrix(QMatrix4x4 &inTransform)
{
    flags.setFlag(Flag::TransformDirty);

    // clear pivot
    pivot[0] = pivot[1] = pivot[2] = 0.0f;

    // set translation
    position[0] = inTransform(3, 0);
    position[1] = inTransform(3, 1);
    position[2] = inTransform(3, 2);
    // set scale
    const QVector3D column0(inTransform(0, 0), inTransform(0, 1), inTransform(0, 2));
    const QVector3D column1(inTransform(1, 0), inTransform(1, 1), inTransform(1, 2));
    const QVector3D column2(inTransform(2, 0), inTransform(2, 1), inTransform(2, 2));
    scale[0] = vec3::magnitude(column0);
    scale[1] = vec3::magnitude(column1);
    scale[2] = vec3::magnitude(column2);
    // make sure there is no zero value
    scale[0] = (scale[0] == 0.0f) ? 1.0f : scale[0];
    scale[1] = (scale[1] == 0.0f) ? 1.0f : scale[1];
    scale[2] = (scale[2] == 0.0f) ? 1.0f : scale[2];

    // extract rotation by first dividing through scale value
    float invScaleX = 1.0f / scale[0];
    float invScaleY = 1.0f / scale[1];
    float invScaleZ = 1.0f / scale[2];

    inTransform(0, 0) *= invScaleX;
    inTransform(0, 1) *= invScaleX;
    inTransform(0, 2) *= invScaleX;
    inTransform(1, 0) *= invScaleY;
    inTransform(1, 1) *= invScaleY;
    inTransform(1, 2) *= invScaleY;
    inTransform(2, 0) *= invScaleZ;
    inTransform(2, 1) *= invScaleZ;
    inTransform(2, 2) *= invScaleZ;

    float rotationMatrixData[9] = { inTransform(0, 0), inTransform(0, 1), inTransform(0, 2),
                                    inTransform(1, 0), inTransform(1, 1), inTransform(1, 2),
                                    inTransform(2, 0), inTransform(2, 1), inTransform(2, 2) };

    QMatrix3x3 theRotationMatrix(rotationMatrixData);
    rotation = QQuaternion::fromRotationMatrix(theRotationMatrix).normalized();
}

void QSSGRenderNode::addChild(QSSGRenderNode &inChild)
{
    // Adding children to a layer does not reset parent
    // because layers can share children over with other layers
    if (type != QSSGRenderNode::Type::Layer) {
        if (inChild.parent && inChild.parent != this)
            inChild.parent->removeChild(inChild);
        inChild.parent = this;
    }
    children.push_back(inChild);
}

void QSSGRenderNode::removeChild(QSSGRenderNode &inChild)
{
    if (Q_UNLIKELY(type != QSSGRenderNode::Type::Layer && inChild.parent != this)) {
        Q_ASSERT(inChild.parent == this);
        return;
    }

    inChild.parent = nullptr;
    children.remove(inChild);
}

void QSSGRenderNode::removeFromGraph()
{
    if (parent)
        parent->removeChild(*this);

    // Orphan all of my children.
    for (auto it = children.begin(), end = children.end(); it != end;) {
        auto &removedChild = *it++;
        children.remove(removedChild);
        removedChild.parent = nullptr;
    }
}

QSSGBounds3 QSSGRenderNode::getBounds(const QSSGRef<QSSGBufferManager> &inManager,
                                      bool inIncludeChildren) const
{
    QSSGBounds3 retval;
    if (inIncludeChildren)
        retval = getChildBounds(inManager);

    if (type == QSSGRenderGraphObject::Type::Model)
        retval.include(static_cast<const QSSGRenderModel *>(this)->getModelBounds(inManager));
    return retval;
}

QSSGBounds3 QSSGRenderNode::getChildBounds(const QSSGRef<QSSGBufferManager> &inManager) const
{
    QSSGBounds3 retval;
    QSSGBounds3 childBounds;
    for (auto &child : children) {
        if (child.flags.testFlag(Flag::TransformDirty))
            child.calculateLocalTransform();
        childBounds = child.getBounds(inManager);
        if (!childBounds.isEmpty()) {
            // Transform the bounds into our local space.
            childBounds.transform(child.localTransform);
            retval.include(childBounds);
        }
    }
    return retval;
}

QVector3D QSSGRenderNode::getGlobalPos() const
{
    return QVector3D(globalTransform(0, 3), globalTransform(1, 3), globalTransform(2, 3));
}

QVector3D QSSGRenderNode::getDirection() const
{
    const float *dataPtr(globalTransform.data());
    QVector3D retval(dataPtr[8], dataPtr[9], dataPtr[10]);
    retval.normalize();
    return retval;
}

QVector3D QSSGRenderNode::getScalingCorrectDirection() const
{
    // ### This code has been checked to be corect
    QMatrix3x3 theDirMatrix = mat44::getUpper3x3(globalTransform);
    theDirMatrix = mat33::getInverse(theDirMatrix).transposed();
    QVector3D theOriginalDir(0, 0, -1);
    QVector3D retval = mat33::transform(theDirMatrix, theOriginalDir);
    // Should already be normalized, but whatever
    retval.normalize();
    return retval;
}

QVector3D QSSGRenderNode::getGlobalPivot() const
{
    QVector3D retval(position);
    retval.setZ(retval.z() * -1);

    if (parent && parent->type != QSSGRenderGraphObject::Type::Layer) {
        const QVector4D direction(retval.x(), retval.y(), retval.z(), 1.0f);
        const QVector4D result = parent->globalTransform * direction;
        return QVector3D(result.x(), result.y(), result.z());
    }

    return retval;
}

void QSSGRenderNode::calculateMVPAndNormalMatrix(const QMatrix4x4 &inViewProjection, QMatrix4x4 &outMVP, QMatrix3x3 &outNormalMatrix) const
{
    outMVP = inViewProjection * globalTransform;
    outNormalMatrix = calculateNormalMatrix();
}

QMatrix3x3 QSSGRenderNode::calculateNormalMatrix() const
{
    QMatrix3x3 outNormalMatrix = mat44::getUpper3x3(globalTransform);
    return mat33::getInverse(outNormalMatrix).transposed();
}

QT_END_NAMESPACE
