/*****************************************************************************************
 * imgToDxt: converts a single image to a dxt-compressed image
 *
 * Copyright (C) 2007 Electronic Visualization Laboratory,
 * University of Illinois at Chicago
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the distribution.
 *  * Neither the name of the University of Illinois at Chicago nor
 *    the names of its contributors may be used to endorse or promote
 *    products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Direct questions, comments etc to www.evl.uic.edu/cavern/forum
 *
 * Author: Ratko Jagodic
 *
 *****************************************************************************************/



#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <wand/magick-wand.h>

//#if MagickLibVersion >= 0x645
//#define MagickGetImagePixels MagickGetAuthenticPixels
//#endif

// for dxt compression
#include "libdxt.h"


using namespace std;


#define ThrowWandException(wand)		\
  {						\
    char					\
      *description;				\
						\
    ExceptionType				\
      severity;					\
						    \
    description=MagickGetException(wand,&severity);			\
    (void) fprintf(stderr,"%s %s %ld %s\n",GetMagickModule(),description); \
    description=(char *) MagickRelinquishMemory(description);		\
    exit(-1);								\
  }


// -----------------------------------------------------------------------------



void writeDXT(string fileName, byte *buffer, unsigned int width, 
	      unsigned int height, unsigned int numBytes)
{
    fprintf(stderr, "\nImgToDxt: Writing DXT to file... %u bytes", numBytes);

    unsigned long r;
    FILE *f = fopen(fileName.data(), "wb");

    if (f != NULL)
    {
	// write the size of the image in the first 8 bytes
	r = fwrite(&width, sizeof(unsigned int), 1, f);
	r = fwrite(&height, sizeof(unsigned int), 1, f);
	r = fwrite(&numBytes, sizeof(unsigned int), 1, f);
	
	// write the buffer out to the file
	r = fwrite(buffer, 1, numBytes, f);
	fclose(f);
    }
    else
	fprintf(stderr, "\nImgToDxt: ERROR: Unable to write DXT file. Check dir permissions.");
}



void getRGBA(string fileName, byte **rgba, unsigned int &width, 
	      unsigned int &height)
{
    // use ImageMagick to read all other formats
    MagickBooleanType status;  
    MagickWand *wand;
    
    // read file
    wand=NewMagickWand();  
    status=MagickReadImage(wand, fileName.data());
    if (status == MagickFalse)
	ThrowWandException(wand);

    // get the image size
    width = MagickGetImageWidth(wand);
    height = MagickGetImageHeight(wand);

    if (width%4 != 0 || height%4 != 0)
    {
	fprintf(stderr, "\nImgToDxt: Image cropped a few pixels to be a multiple of 4 for dxt");
	width -= width%4;
	height -= height%4;
    }
	
    // flip the image to have the correct orientation for dxt
    MagickFlipImage(wand);
    
    // get the pixels
    *rgba = (byte*) memalign(16, width*height*4);
    memset(*rgba, 0, width*height*4);
    MagickGetImagePixels(wand, 0, 0, width, height, "RGBA", CharPixel, *rgba);
    DestroyMagickWand(wand);
}


void rgbaToDXT(string fileName, byte **rgba, byte **dxt, unsigned int width, 
	       unsigned int height)
{
    unsigned int numBytes;

    // compress into DXT
    *dxt = (byte*) memalign(16, width*height*4/8);
    memset(*dxt, 0, width*height*4/8);
    numBytes = CompressDXT(*rgba, *dxt, width, height, FORMAT_DXT1, 1);

    // write this DXT out to a file (change extension to .dxt)
    string dxtFileName = string(fileName);
    dxtFileName.resize(fileName.rfind("."));
    dxtFileName += ".dxt";
    writeDXT(dxtFileName, *dxt, width, height, numBytes);
}


bool dxtFileExists(string fileName)
{
    // replace the extension with .dxt
    string dxtFileName = string(fileName);
    dxtFileName.resize(fileName.rfind("."));
    dxtFileName += ".dxt";

    // check whether the file exists by trying to open it
    FILE *dxtFile = fopen(dxtFileName.data(), "r");
    if ( dxtFile == NULL)
    {
	fprintf(stderr, "\nImgToDxt: DXT file for %s doesn't exist yet.", fileName.data());
	return false;
    }
    else 
    {
	fclose(dxtFile);
	return true;
    }
}


// -----------------------------------------------------------------------------



int main(int argc,char **argv)
{
    byte *dxt = NULL;   
    byte *rgba = NULL;
    unsigned int width, height;  // image size
     
    
    // parse command line arguments
    if (argc < 2){
	fprintf(stderr, "\n\nUSAGE: imgToDxt filename\n");
	return 0;
    }

    // check file extension
    string fileName, fileExt;
    fileName = string(argv[1]);
    fileExt = fileName.substr(fileName.rfind("."));

    // if image is in DXT load it directly, otherwise compress and load
    if(fileExt.compare(".dxt") == 0 || dxtFileExists(fileName))   // DXT already exists
	return(0);
    else                               // all other image formats
    {
	getRGBA(fileName, &rgba, width, height);
	rgbaToDXT(fileName, &rgba, &dxt, width, height);
	free(dxt);
	free(rgba);
    }

    return(0);
}