#region LGPL License
/*
Axiom Game Engine Library
Copyright (C) 2003 Axiom Project Team
The overall design, and a majority of the core engine and rendering code
contained within this library is a derivative of the open source Object Oriented
Graphics Engine OGRE, which can be found at http://ogre.sourceforge.net.
Many thanks to the OGRE team for maintaining such a high quality project.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#endregion
using System;
using System.IO;
namespace Axiom.Core{
/// <summary>
/// Abstract class reprensenting a loadable resource (e.g. textures, sounds etc)
/// </summary>
/// <remarks>
/// Resources are generally passive constructs, handled through the
/// ResourceManager abstract class for the appropriate subclass.
/// The main thing is that Resources can be loaded or unloaded by the
/// ResourceManager to stay within a defined memory budget. Therefore,
/// all Resources must be able to load, unload (whilst retainin enough
/// info about themselves to be reloaded later), and state how big they are.
///
/// Subclasses must implement:
/// 1. A constructor, with at least a mandatory name param.
/// This constructor must set name and optionally size.
/// 2. The Load() and Unload() methods - size must be set after Load()
/// Each must check & update the isLoaded flag.
/// </remarks>
public abstract class Resource : IDisposable {
#region Fields
/// <summary>
/// Name of this resource.
/// </summary>
protected string name;
/// <summary>
/// Has this resource been loaded yet?
/// </summary>
protected bool isLoaded;
/// <summary>
/// Size (in bytes) that this resource takes up in memory.
/// </summary>
protected long size;
/// <summary>
/// Timestamp of the last time this resource was accessed.
/// </summary>
protected long lastAccessed;
/// <summary>
/// Unique handle of this resource.
/// </summary>
protected int handle;
#endregion Fields
#region Constructors
/// <summary>
/// Default constructor.
/// </summary>
/// <remarks>Subclasses must initialize name and size.</remarks>
public Resource() {
isLoaded = false;
size = 0;
}
#endregion
#region Virtual/Abstract methods
/// <summary>
/// Loads the resource, if not loaded already.
/// </summary>
public abstract void Load();
/// <summary>
/// Unloads the resource data, but retains enough info. to be able to recreate it
/// on demand.
/// </summary>
public virtual void Unload() {}
#endregion
#region Properties
/// <summary>
/// Size of this resource.
/// </summary>
public long Size {
get {
return size;
}
}
/// <summary>
/// Name of this resource.
/// </summary>
public string Name {
get {
return name;
}
}
/// <summary>
/// Is this resource loaded?
/// </summary>
public bool IsLoaded {
get {
return isLoaded;
}
}
/// <summary>
/// The time the resource was last touched.
/// </summary>
public long LastAccessed {
get {
return lastAccessed;
}
}
/// <summary>
/// Gets/Sets the unique handle of this resource.
/// </summary>
public int Handle {
get {
return handle;
}
set {
handle = value;
}
}
#endregion
#region Public methods
/// <summary>
/// Indicates this resource has been used.
/// </summary>
public virtual void Touch() {
lastAccessed = Root.Instance.Timer.Milliseconds;
if(!isLoaded) {
Load();
}
}
#endregion
#region Implementation of IDisposable
/// <summary>
/// Dispose method. Made virtual to allow subclasses to destroy resources their own way.
/// </summary>
public virtual void Dispose() {
if(isLoaded) {
// unload this resource
Unload();
}
}
#endregion
}
}
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