Creating Your First Editor Plugin

#include "MaterialsModel.h"
#include <UnigineGUID.h>
#include <UnigineMaterials.h>
#include "QtMetaTypes.h"

#include <QDebug>

using Unigine::UGUID;

namespace Materials
{

////////////////////////////////////////////////////////////////////////////////
// MaterialsModel::Item.
////////////////////////////////////////////////////////////////////////////////
class MaterialsModel::Item
{
public:
	static Item *createRootItem(MaterialsModel *model);

	Item(Item *parent, MaterialsModel *model, const UGUID &guid);
	~Item();

	QModelIndex index() const;

	void append(Item *item);
	Item *child(int idx);
	Item *find(const UGUID &guid) const;
	int childCount() const;

	Item *parent();
	int row() const;
	QVariant data(int role) const;

	void fetchMore();
	bool canFetchMore() const;

private:
	Item *parent_ = nullptr; // Not owned.
	MaterialsModel *model_ = nullptr; // Not owned.
	QVector<Item *> children_; // Owned.
	UGUID guid_;
};

MaterialsModel::Item *MaterialsModel::Item::createRootItem(MaterialsModel *model)
{
	Item *root = new Item(nullptr, model, UGUID());
	const int size = Unigine::Materials::getNumMaterials();
	for (int i = 0; i < size; ++i)
	{
		const Unigine::MaterialPtr mat = Unigine::Materials::getMaterial(i);
		if (mat->isHidden())
		{
			continue;
		}
		if (const Unigine::MaterialPtr &parent_mat = mat->getParent())
		{
			if (!parent_mat->isHidden())
			{
				continue;
			}
		}
		root->children_.push_back(new Item(root, model, mat->getGUID()));
	}
	return root;
}

MaterialsModel::Item::Item(Item *parent, MaterialsModel *model, const UGUID &guid)
	: parent_(parent), model_(model), guid_(guid)
{
}

MaterialsModel::Item::~Item()
{
	qDeleteAll(children_);
}

QModelIndex MaterialsModel::Item::index() const
{
	if (!parent_ || guid_.isEmpty())
	{
		return QModelIndex();
	}
	return model_->createIndex(row(), 0, const_cast<Item *>(this));
}

void MaterialsModel::Item::append(Item *item)
{
	const int size = children_.size();
	model_->beginInsertRows(index(), size, size);
	item->parent_ = this;
	children_.push_back(item);
	model_->endInsertRows();
}

auto MaterialsModel::Item::child(int idx) -> Item *
{
	return ((idx >= 0) && (idx < children_.size()))
		? children_[idx]
		: nullptr;
}

auto MaterialsModel::Item::find(const UGUID &guid) const -> Item *
{
	for (Item *child: children_)
	{
		if (child->guid_ == guid)
		{
			return child;
		}
		if (child->canFetchMore())
		{
			child->fetchMore();
		}
		if (Item *grandchild = child->find(guid))
		{
			return grandchild;
		}
	}
	return nullptr;
}

int MaterialsModel::Item::childCount() const
{
	if (!guid_.isValid())
	{
		return children_.size();
	}

	const Unigine::MaterialPtr mat = Unigine::Materials::findMaterialByGUID(guid_);
	int count = mat->getNumChildren();
	for (int i = count - 1; i >= 0; --i)
	{
		if (mat->getChild(i)->isHidden())
		{
			--count;
		}
	}
	return count;
}

MaterialsModel::Item *MaterialsModel::Item::parent()
{
	return parent_;
}

int MaterialsModel::Item::row() const
{
	if (parent_)
	{
		return parent_->children_.indexOf(const_cast<Item *>(this));
	}
	return 0;
}

QVariant MaterialsModel::Item::data(int role) const
{
	if (Qt::DisplayRole == role)
	{
		const Unigine::MaterialPtr &mat = Unigine::Materials::findMaterialByGUID(guid_);
		return QVariant::fromValue(QString(mat->getName()));
	}
	if (MaterialsModel::GUID_ROLE == role)
	{
		return QVariant::fromValue(guid_);
	}
	return QVariant();
}

void MaterialsModel::Item::fetchMore()
{
	const Unigine::MaterialPtr &mat = Unigine::Materials::findMaterialByGUID(guid_);
	const int size = mat->getNumChildren();
	QVector<Item *> items;
	items.reserve(size);

	for (int i = 0; i < size; ++i)
	{
		const Unigine::MaterialPtr child_mat = mat->getChild(i);
		if (child_mat->isHidden())
		{
			continue;
		}
		items.push_back(new Item(this, model_, child_mat->getGUID()));
	}

	if (items.empty())
	{
		return;
	}

	const int cur_size = children_.size();
	model_->beginInsertRows(index(), cur_size, cur_size + items.size() - 1);
	std::copy(std::begin(items), std::end(items), std::back_inserter(children_));
	model_->endInsertRows();
}

bool MaterialsModel::Item::canFetchMore() const
{
	return children_.empty() && childCount();
}

////////////////////////////////////////////////////////////////////////////////
// MaterialsModel.
////////////////////////////////////////////////////////////////////////////////
MaterialsModel::MaterialsModel(QObject *parent)
	: QAbstractItemModel(parent)
	, root_(Item::createRootItem(this))
{
}

MaterialsModel::~MaterialsModel()
{
	delete root_;
}

QModelIndex MaterialsModel::index(int row, int column, const QModelIndex &parent) const
{
	if (column > 0)
	{
		return {};
	}

	Item *parent_item = nullptr;
	if (!parent.isValid())
	{
		parent_item = root_;
	}
	else
	{
		parent_item = static_cast<Item *>(parent.internalPointer());
	}

	Item *child_item = parent_item->child(row);
	return child_item
		? createIndex(row, column, child_item)
		: QModelIndex();
}

QModelIndex MaterialsModel::index(const UGUID &guid) const
{
	if (guid.isEmpty())
	{
		return QModelIndex();
	}
	Item *item = root_->find(guid);
	return item ? item->index() : QModelIndex();
}

QModelIndex MaterialsModel::parent(const QModelIndex &child) const
{
	if (!child.isValid())
	{
		return QModelIndex();
	}
	Item *child_item = static_cast<Item *>(child.internalPointer());
	Item *parent_item = child_item->parent();

	return (parent_item != root_)
		? createIndex(parent_item->row(), 0, parent_item)
		: QModelIndex();
}

int MaterialsModel::rowCount(const QModelIndex &parent) const
{
	if (parent.column() > 0)
	{
		return 0;
	}

	Item *parent_item = nullptr;
	if (!parent.isValid())
	{
		parent_item = root_;
	}
	else
	{
		parent_item = static_cast<Item *>(parent.internalPointer());
	}

	return parent_item->childCount();
}

int MaterialsModel::columnCount(const QModelIndex &parent) const
{
	return 1;
}

QVariant MaterialsModel::data(const QModelIndex &index, int role) const
{
	if (!index.isValid())
	{
		return QVariant();
	}

	Item *item = static_cast<Item *>(index.internalPointer());
	return item->data(role);
}

void MaterialsModel::fetchMore(const QModelIndex &parent)
{
	if (!parent.isValid())
	{
		return;
	}
	Item *item = static_cast<Item *>(parent.internalPointer());
	item->fetchMore();
}

bool MaterialsModel::canFetchMore(const QModelIndex &parent) const
{
	if (!parent.isValid())
	{
		return false;
	}
	Item *item = static_cast<Item *>(parent.internalPointer());
	return item->canFetchMore();
}

} // namespace Materials

#pragma once

// including UnigineGUID.h containing definition of the metatype we're going to declare
#include <UnigineGUID.h>

// including QMetaType to be able to declare metatypes
#include <QMetaType>

// registering the Unigine::UGUID type to make it known to Qt's meta-object system
Q_DECLARE_METATYPE(Unigine::UGUID)