textureutils.h

这是在s60第五版上用Open GL开发的软件

		/** Listener that is notified when an image has been loaded. */
		MImageHandlerCallback& iCallback;
		/** Bitmap (owned by the user of this class) where the loaded image data is put. */
		CFbsBitmap *iBitmap;
		/** Bitmap mask (owned by the user of this class) where the loaded alpha channel data is put. */
		CFbsBitmap *iBitmapMask;
		/** File server (owned by the user of this class) that is used to load the raw image data from files. */
		RFs& iFs;
		/** Current image frame information. */
		TFrameInfo iFrameInfo;
    };


// =============================================================================
// =============================================================================
/**
 * Texture manager implementation that makes loading of texture bitmaps a lot easier.
 *
 * As bitmap loading/converting operations on Symbian OS
 * (class CImageDecoder) are asynchronous, the task of loading textures from
 * bitmaps becomes very complex. Especially when it comes to loading several
 * textures. This class can be used to reduce that complexity by
 * handling all the texture loading/deleting, color keying and blitting
 * operations.
 *
 * The texture loading events can be listened by implementing a MTextureLoadingListener.
 *
 */
class CTextureManager: public CFiniteStateMachine, public MImageHandlerCallback
	{
	public: // Constructor and destructor
		/**
		 * Factory method that creates a texture manager that uses the application's private
		 * storage path as the texture path. This is the default place where all applications
		 * in the Symbian security framework should store their private data.
		 * @param aScreenWidth Width of the screen in pixels.
		 * @param aScreenHeight Height of the screen in pixels.
		 * @param aFrustumBottom Bottom clipping plane.
		 * @param aFrustumTop Top horizontal clipping plane.
		 * @param aFrustumLeft Left vertical clipping plane.
		 * @param aFrustumRight Right vertical clipping plane.
		 * @param aFrustumNear Distance to the near depth clipping plane.
		 * @param aTextureLoadingListener Pointer to a MTextureLoadingListener class that is notified of textures loading operations.
 		 */
		static CTextureManager* NewL(
			GLuint aScreenWidth, GLuint aScreenHeight,
			GLfloat aFrustumTop, GLfloat aFrustumBottom,
			GLfloat aFrustumRight, GLfloat aFrustumLeft, GLfloat aFrustumNear,
			MTextureLoadingListener * aTextureLoadingListener = NULL);

		/**
		 * Factory method that creates a texture manager that uses the given texture path.
		 * @param aTexturePath Full path to the directory where textures are stored.
		 * @param aScreenWidth Width of the screen in pixels.
		 * @param aScreenHeight Height of the screen in pixels.
		 * @param aFrustumBottom Bottom clipping plane.
		 * @param aFrustumTop Top horizontal clipping plane.
		 * @param aFrustumLeft Left vertical clipping plane.
		 * @param aFrustumRight Right vertical clipping plane.
		 * @param aFrustumNear Distance to the near depth clipping plane.
		 * @param aTextureLoadingListener Pointer to a MTextureLoadingListener class that is notified of textures loading operations.
 		 */
		static CTextureManager* NewL( TFileName & aTexturePath,
			GLuint aScreenWidth, GLuint aScreenHeight,
			GLfloat aFrustumTop, GLfloat aFrustumBottom,
			GLfloat aFrustumRight, GLfloat aFrustumLeft, GLfloat aFrustumNear,
			MTextureLoadingListener * aTextureLoadingListener = NULL);

        /**
         * Destructor. Deletes the internal CImageHandler and CFsbBitmap objects.
         * Also destroys all the textures that were loaded using this texture manager
         * and finally closes the file server that was given in the constructor.
         */
		virtual ~CTextureManager();

	public: // New functions
		/**
		 * States of the CTextureManager finite state machine.
		 *  EIdle indicates that the object is in idle
		 *  ELoading indicates that the object is loading the textures.
		 */
		enum { EIdle, ELoading };

		/**
		 * Requests a texture to be loaded.
		 * @param aTextureName Name of the file containing the texture. Note: The file must be located in the directory
		 *                     specified by parameter aTexturePath of method CTextureManager::NewL.
		 * @param aTexture Parameter initialized by the texture manager after the texture has been loaded.
		 * @param aMinColorKey Used to specify a min. color key value for the texture. This param. is optional.
		 * @param aMaxColorKey Used to specify a max. color key value for the texture. This param. is optional.
		 * @param aGenerateMipmaps Specifies whether mipmaps should be created for the texture.
 		 */
		void RequestToLoad(const TDesC &aTextureName, TTexture *aTexture,
			TUint8 * aMinColorKey =NULL, TUint8 * aMaxColorKey = NULL,
            TBool aGenerateMipmaps = EFalse);

		/**
 		 * Starts the texture loading. All textures added with RequestToLoad() before calling this method
 		 * are loaded. The progress of texture loading is notified to the MTextureLoadingListener given
 		 * in the constructor.
		 */
		void DoLoadL();

		/**
 		 * If the state that is leaved is ELoading then the registered MTextureLoadingListener instance's
 		 * OnEndLoadingTexturesL method is called to notify that texture loading is now finished.
		 */
		void OnLeaveStateL( TInt aState );
		/**
		 * If the state that is entered is ELoading then the registered MTextureLoadingListener instance's
 		 * OnStartLoadingTexturesL method is called to notify that texture loading is starting.
 		 * After this the textures that have been requested to be loaded are loaded.
		 */
		void OnEnterStateL( TInt );

        /**
         * Implementation of the MImageHandlerCallback method. Gets called when the underlying ImageHandler
         * finished loading one image.
         */
		void ImageOperationCompleteL(TInt aError);

		/**
		 * Performs a 2D blit using OpenGL ES by rendering a textured polygon on the near depth clipping plane.
		 * This method supports alpha blending, color keying and stretching (or shrinking) of the blitted
		 * texture.
		 * @param aTexture Texture to be blitted to the screen.
		 * @param aX1 Upper left X screen coordinate of the rectangle where the texture is to be blitted.
		 * @param aY1 Upper left Y screen coordinate of the rectangle where the texture is to be blitted.
		 * @param aX2 Lower right X screen coordinate of the rectangle where the texture is to be blitted.
		 * @param aY2 Lower right Y screen coordinate of the rectangle where the texture is to be blitted.
 		 */
		void Blit(TTexture & aTexture, GLuint aX1, GLuint aY1, GLuint aX2, GLuint aY2);
		/**
		 * Performs a 2D blit using OpenGL ES by rendering a textured polygon on the near depth clipping plane.
		 * This method supports alpha blending and color keying. The texture is blitted with it's default size.
		 * @param aTexture Texture to be blitted to the screen.
		 * @param aX Upper left X screen coordinate where the texture is to be blitted.
		 * @param aY Upper left Y screen coordinate where the texture is to be blitted.
		 */
		void Blit(TTexture & aTexture, GLuint aX, GLuint aY);

        /**
         * Sets the screen width and height. Must be called if the screen size changes during execution
         * of the program and if the Blit() method are used as screen width and height values are used in the Blit() methods.
         * @param aScreenWidth New screen width to be used. Zero values are ignored (the old screen width is used if this value is zero).
         * @param aScreenHeight New screen height to be used.  Zero values are ignored (the old screen height is used if this value is zero).
         */
		void SetScreenSize( GLuint aScreenWidth, GLuint aScreenHeight );

	protected: // New functions

		/**
		 * Loads the next texture in the loading queue.
		 */
		void LoadNextTextureL();

		/**
		 * Deletes named textures (the OpenGL ES assigned name) by calling glDeleteTextures.
		 * After this the internal texture name array and the textures are deleted.
		 * WARNING! The CTextureManager instance can't be used after calling this method.
		 */
		void DeleteTextures();

		/**
		 * Checks if the given texture has already been loaded.
		 * If it has been loaded this method returns a pointer to the struct TTexture containing all the information.
		 * If it hasn't been loaded this method returns NULL.
		 * @param aTextureName Name of the texture.
		 * @return TTexture structure containing the information for the texture or NULL if the texture wasn't yet loaded.
		 */
		TTexture * TextureExists( const TDesC &aTextureName);

	protected:

		/**
		 * Default C++ and Symbian ConstructL are placed in protected
		 * area to force the use of NewL when creating an instance.
		 */
		CTextureManager();

		/**
		 * Constructor that creates a texture manager that uses the application's private
		 * storage path as the texture path. This is the default place where all applications
		 * in the Symbian security framework should store their private data.
 		 * @param aTexturePath Full path to the directory where textures are stored.
		 * @param aScreenWidth Width of the screen in pixels.
		 * @param aScreenHeight Height of the screen in pixels.
		 * @param aFrustumBottom Bottom clipping plane.
		 * @param aFrustumTop Top horizontal clipping plane.
		 * @param aFrustumLeft Left vertical clipping plane.
		 * @param aFrustumRight Right vertical clipping plane.
		 * @param aFrustumNear Distance to the near depth clipping plane.
		 * @param aTextureLoadingListener Reference to a MTextureLoadingListener client class which observe the textures loading operations.
 		 */
		void ConstructL( TFileName & aTexturePath,
			GLuint aScreenWidth, GLuint aScreenHeight,
			GLfloat aFrustumTop, GLfloat aFrustumBottom,
			GLfloat aFrustumRight, GLfloat aFrustumLeft, GLfloat aFrustumNear,
			MTextureLoadingListener * aTextureLoadingListener = NULL );

		/**
		 * Constructor that creates a texture manager that uses the given path as the texture path.
		 * @param aScreenWidth Width of the screen in pixels.
		 * @param aScreenHeight Height of the screen in pixels.
		 * @param aFrustumBottom Bottom clipping plane.
		 * @param aFrustumTop Top horizontal clipping plane.
		 * @param aFrustumLeft Left vertical clipping plane.
		 * @param aFrustumRight Right vertical clipping plane.
		 * @param aFrustumNear Distance to the near depth clipping plane.
		 * @param aTextureLoadingListener Pointer to a MTextureLoadingListener class that is notified of textures loading operations.
  		 */
		void ConstructL(
			GLuint aScreenWidth, GLuint aScreenHeight,
			GLfloat aFrustumTop, GLfloat aFrustumBottom,
			GLfloat aFrustumRight, GLfloat aFrustumLeft, GLfloat aFrustumNear,
			MTextureLoadingListener * aTextureLoadingListener = NULL );

	private:
		/** Directory where the textures are loaded from. */
		TFileName iTexturePath;
		/** Loading queue where all the textures about to be loaded are stored. */
		TSglQue<TTexture> iLoadingQueue;
		/** Loading queue iterator. */
		TSglQueIter<TTexture> iLoadingQueueIterator;
		/** Reference to a MTextureLoadingListener object that gets notified of texture loading progress. */
		MTextureLoadingListener * iTextureLoadingListener;

		/** Texture that is currently being loaded. */
		TTexture * iCurrentRequest;
		/** CImageHandler object that will perform the individual image loading/converting operations. */
		CImageHandler* iBmapUtil;

		/** File server that is used to load the raw texture data. */
		RFs iFs;

		/** Array in which the OpenGL ES generated texture names (ids) are stored. */
		GLuint * iTextureNames;
		/** Lenght of iTextureNames. */
		TInt iTextureNameCount;
		/** Variable used to index iTextureNames. */
		TInt iIndex;
		/** Bitmap object that is currently being loaded. */
		CFbsBitmap * iBitmap;
		/** Bitmap mask object that is currently being loaded. */
		CFbsBitmap * iBitmapMask;
		/** Coordinate for the bottom horizontal clipping plane. */
		GLfloat iFrustumBottom;
		/** Coordinate for the top horizontal clipping plane. */
		GLfloat iFrustumTop;
		/** Coordinate for the left vertical clipping plane. */
		GLfloat iFrustumLeft;
		/** Coordinate for the right vertical clipping plane. */
		GLfloat iFrustumRight;
		/** Distance to the near depth clipping plane. */
		GLfloat iFrustumNear;
		/** View frustum width (equals iFrustumRight-iFrustumLeft). */
		GLfloat iFrustumWidth;
		/** View frustum height (equals iFrustumTop-iFrustumBottom). */
		GLfloat iFrustumHeight;
        /** Screen width in pixels. */
		GLuint iScreenWidth;
		/** Screen height in pixels. */
		GLuint iScreenHeight;
	};

/**
 * Returns the root directory of an application in the form [drive-letter]:\[path]\
 * @return Application's root directory.
 */
static TFileName utilGetAppRootDirectoryL();

#endif