class Image;

#ifndef IMAGE_H
#define IMAGE_H


#include <fstream>

using namespace std;


/*
 * definitions for channel values.  for example,
 *    image->getPixel(0,0,GREEN);
 * gets the green value at pixel 0,0 in image.
 */
#define RED	0
#define GREEN	1
#define BLUE	2



/*
 * struct to contain an entire pixel's data, up to three channels.  if
 * only one channel then all bur r values in
 * this struct will be ignored.  
 */
typedef struct
{
	double		r;
	double		g;
	double		b;
} Pixel;


/*
 * generic multi channel 8-bit max image class.  can read and write
 * 8 and 24 bit uncompressed BMP files and supports some useful OpenGL 
 * calls.
 *
 * get and set pixel methods use doubles from 0.0 to 1.0.  these 
 * values are mapped to integer values from 0 to the maximum value
 * allowed by the number of bits per channel in the image.
 */
class Image
{
  public:
			Image ();
			~Image ();

			// create empty image with specified characteristics
			Image (int width_, int height_);
			Image (int width_, int height_, int channels_);
			Image (int width_, int height_, int channels_, 
				int bits_);

			// create image and read data from filename
			// use good() or bad() to check success
			Image (const char* filename);

			// copy constructor and assignment operator
			// _deep_ copy!
			Image (const Image& image);
			Image&		operator= (const Image& image);

			// accessors
			int		getWidth ()    { return width;    }
			int		getHeight ()   { return height;   }
			int		getChannels () { return channels; }
			int		getBits ()     { return bits;     }

			// check if the image is valid
			bool		good ();
			bool		bad ();

			// set all the pixel data to zero
			void		clear ();

			// retrieve pixel data.  methods with _ at the
			// end of their name return 0.0 if the x and y
			// coordinates are out of range.  the functions
			// without a _ give an assertion failur for out
			// of bounds coordinates
			double		getPixel  (int x, int y, int channel);
			double		getPixel_ (int x, int y, int channel);
			Pixel		getPixel  (int x, int y);
			Pixel		getPixel_ (int x, int y);
			Pixel&		getPixel  (int x, int y, Pixel& pixel);
			Pixel&		getPixel_ (int x, int y, Pixel& pixel);

			// set pixel data.  set is ignored by functions with a _
			// at the end of the name when the coordinates or the pixel
			// value are out of bounds.  the functions without an _
			// after the name give an assertion failure for out of
			// bounds
			// 
			void		setPixel  (int x, int y, int channel, double value);
			void		setPixel_ (int x, int y, int channel, double value);
			void		setPixel  (int x, int y, Pixel& pixel);
			void		setPixel_ (int x, int y, Pixel& pixel);

			// OpenGL call wrappers
			void		glDrawPixelsWrapper ();
			void		glTexImage2DWrapper ();
			void		glReadPixelsWrapper ();

			// top-level file read and write calls,
			// determines file type
			int		read (const char* filename);
			int		write (const char* filename);

			// BMP specific read and write calls
			int		readBMP (const char* filename);
			int		readBMP (ifstream& file);
			int		writeBMP (const char* filename);
			int		writeBMP (ofstream& file);

			

  private:

	int		index(int x, int y, int c);

	int		width;
	int		height;
	int		channels;	// number of channels
	int		bits;		// number of bits per pixel per channel
	int		maxValue;	// max that can be stored in bits

	unsigned char*	pixels;		// image data

};


#endif // IMAGE_H