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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 "config.h"
namespace unity
{
namespace
{
// Stolen from boost
template <class T>
inline std::size_t hash_combine(std::size_t seed, T const& v)
{
return seed ^ (std::hash<T>()(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2));
}
}
TextureCache& TextureCache::GetDefault()
{
static TextureCache instance;
return instance;
}
nux::BaseTexture* TextureCache::DefaultTexturesLoader(std::string const& name, int w, int h)
{
int size = std::max(w, h);
return nux::CreateTexture2DFromFile((PKGDATADIR"/" + name).c_str(), (size <= 0 ? -1 : size), true);
}
std::size_t TextureCache::Hash(std::string const& id, int width, int height)
{
return hash_combine(hash_combine(std::hash<std::string>()(id), width), height);
}
TextureCache::BaseTexturePtr TextureCache::FindTexture(std::string const& texture_id,
int width, int height,
CreateTextureCallback factory)
{
if (!factory)
return BaseTexturePtr();
auto key = Hash(texture_id, width, height);
auto texture_it = cache_.find(key);
BaseTexturePtr texture(texture_it != cache_.end() ? texture_it->second : nullptr);
if (!texture)
{
texture.Adopt(factory(texture_id, width, height));
if (!texture)
return texture;
// 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.
cache_.insert({key, texture.GetPointer()});
auto on_destroy = sigc::mem_fun(this, &TextureCache::OnDestroyNotify);
texture->OnDestroyed.connect(sigc::bind(on_destroy, key));
}
return texture;
}
void TextureCache::Invalidate(std::string const& texture_id, int width, int height)
{
cache_.erase(Hash(texture_id, width, height));
}
void TextureCache::OnDestroyNotify(nux::Trackable* Object, std::size_t 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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