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