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// -*- Mode: C++; indent-tabs-mode: nil; tab-width: 2 -*-
/*
* Copyright (C) 2010, 2011 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by Gordon Allott <gord.allott@canonical.com>
* Tim Penhey <tim.penhey@canonical.com>
*/
#include "TextureCache.h"
#include <sstream>
#include <NuxCore/Logger.h>
namespace unity
{
namespace
{
nux::logging::Logger logger("unity.internal.texturecache");
}
TextureCache::TextureCache()
{
}
TextureCache::~TextureCache()
{
}
TextureCache& TextureCache::GetDefault()
{
static TextureCache instance;
return instance;
}
std::string TextureCache::Hash(std::string const& id, int width, int height)
{
std::ostringstream sout;
sout << id << "-" << width << "x" << height;
return sout.str();
}
TextureCache::BaseTexturePtr TextureCache::FindTexture(std::string const& texture_id,
int width, int height,
CreateTextureCallback slot)
{
std::string key = Hash(texture_id, width, height);
BaseTexturePtr texture(cache_[key]);
if (!texture)
{
texture = slot(texture_id, width, height);
// Now here is the magic.
//
// The slot function is required to return a new texture. This has an
// internal reference count of one. The TextureCache wants to hold the
// texture inside the internal map for as long as the object itself
// exists, but it doesn't want any ownership of the texture. How we
// handle this is to always return a smart pointer for the texture. These
// smart pointers have the ownership of the texture.
//
// We also hook into the objects OnDestroyed signal to remove it from the
// map. To avoid a reverse lookup map, we bind the key to the method
// call. By using a mem_fun rather than a lambda function, and through
// the magic of sigc::trackable, we don't need to remember the connection
// itself. We get notified when the object is being destroyed, and if we
// are destroyed first, then the sigc::trackable disconnects all methods
// created using mem_fun.
// Reduce the internal reference count of the texture, so the smart
// pointer is the sole owner of the object.
texture->UnReference();
cache_[key] = texture.GetPointer();
auto on_destroy = sigc::mem_fun(this, &TextureCache::OnDestroyNotify);
texture->OnDestroyed.connect(sigc::bind(on_destroy, key));
}
return texture;
}
void TextureCache::OnDestroyNotify(nux::Trackable* Object, std::string key)
{
cache_.erase(key);
}
// Return the current size of the cache.
std::size_t TextureCache::Size() const
{
return cache_.size();
}
} // namespace unity
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