MTextureCache.h

#ifndef MAYA_API_MTextureCache
#define MAYA_API_MTextureCache

//-
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//+

// MTextureCache.h

// DESCRIPTION: Texture cache, used to temporarily store textures.
//              Eventually, this class will likely end up in the 
//              Maya API.
//
//              This class is not currently thread-safe.
//
// AUTHOR: Christian Laforte
//

#ifdef WIN32
#pragma warning( disable : 4786 )       // Disable stupid STL warnings.
#endif

#include <maya/MObject.h>
#include <map>
#include <string>
#include <algorithm>

#include "MTexture.h"
#include "NodeMonitor.h"


class MTextureCache;

class MTextureCacheElement
{
friend class MTextureCache;

public:
    MTextureCacheElement()
    {
        lastAccessedTimestamp = -1; 
        m_texture = NULL; 
    }
    
    ~MTextureCacheElement();

    MTexture* texture() { return m_texture; }

private:
    MTexture* m_texture;
    unsigned int lastAccessedTimestamp;     // can be used to track when the texture was last used.
    NodeMonitor fMonitor;
};

// This class implements a singleton node with reference counting.
// The refcount starts with a value equal to 0. Everytime instance()
// gets called, the refcount is incremented by one. Everytime
// release() gets called, the refcount is decremented by one,
// and if following that the refcount value is 0, the texture cache
// singleton is destroyed.
class MTextureCache : public NodeMonitorManager
{
protected:
    MTextureCache()
    {
        m_currentTimestamp = 0;
    }

public:
    ~MTextureCache();

    static MTextureCache* instance()
    {
        if (!m_instance)
        {
            m_instance = new MTextureCache;
        }

        refcount++;

        return m_instance;
    }

    static void release()
    {
        refcount--;

        if (refcount == 0 && m_instance)
        {
            delete m_instance;
            m_instance = NULL;
        }
    }

    static int getReferenceCount()
    {
        return refcount;
    }

    // Return a reference to the texture. There's no reference counting yet.
    MTexture* texture(MObject textureObj, 
                 MTexture::Type type = MTexture::RGBA, 
                 bool mipmapped = true,
                 GLenum target = GL_TEXTURE_2D);

    // Returns true if the texture was found and bound; returns false otherwise.
    bool bind(MObject textureObj, 
              MTexture::Type type = MTexture::RGBA, 
              bool mipmapped = true,
              GLenum target = GL_TEXTURE_2D);

    void incrementTimestamp(unsigned int increment=1);

    // Called by a node monitor when the watched node is renamed.
    void onNodeRenamed(MObject& node, MString oldName, MString newName);

private:
    static int refcount;

    std::map<std::string, MTextureCacheElement*> m_textureTable;
    typedef std::map<std::string, MTextureCacheElement*> string_to_cacheElement_map;

    unsigned int m_currentTimestamp;

    static MTextureCache* m_instance;
};



#endif // MAYA_API_MTextureCache