/*
	convert a series of 24bit uncompressed TGA files
	into a POV-Ray 3.1 df3 density file
*/
#include<stdio.h>
#include<stdlib.h>
#include<dir.h>
#include<string.h>

char *fileNames;
char baseName[256];
int nFiles, longestName;

int convert( void );

int main()
{
	char searchName[256];
	char *fName;
	struct ffblk ff;
	int Err;
	int nameLen;

	printf("Enter base name of files to convert ");
	gets( baseName );
	printf("\n");
//strcpy(baseName,"makedf");
	strcpy(searchName,baseName);
	strcat( searchName,"*.tga");
	Err = findfirst(searchName,&ff,0);
	if( Err == -1 )
	{
		printf("Can't find any files matching \'%s\'\n", searchName );
		return 1;
	}
	nFiles = 1;
	longestName = strlen(ff.ff_name);
	while( findnext(&ff) == 0 )
	{
		nFiles++;
		nameLen = strlen(ff.ff_name);
		longestName = max(longestName,nameLen);
	}
	longestName++;
	fileNames = calloc(nFiles,longestName);
	if( !fileNames )
	{
		puts("Couldn't allocate name buffer");
		return 2;
	}
	findfirst(searchName,&ff,0);
	fName = fileNames;
	strcpy( fName, ff.ff_name);
	fName += longestName;
	while( findnext(&ff) == 0 )
	{
		strcpy( fName, ff.ff_name);
		fName += longestName;
	}
	qsort( fileNames, nFiles, longestName, strcmp );
	convert();


	free( fileNames );
	return 0;
}

/* assumes 24bit uncompressed TGA */
int convert( void )
{
	char dfName[256];
	char *fName;
	FILE *tgaFile, *dfFile;
	static int width,height;
	unsigned char d;
	int f,p;
	double i;

	strcpy( dfName, baseName);
	strcat( dfName,".df3");

	/* open first tga to get dimensions */
	tgaFile = fopen( fileNames,"rb");
	fseek( tgaFile, 12,SEEK_SET );
	/* read width,height of first TGA
	   low byte first */
	fread( &d,1,1,tgaFile );
	width = d;
	fread( &d,1,1,tgaFile );
	width += ((int)d) << 8;
	fread( &d,1,1,tgaFile );
	height = d;
	fread( &d,1,1,tgaFile );
	height += ((int)d) << 8;
	fclose( tgaFile );

	dfFile = fopen( dfName,"wb");
	/* write width,height,depth of df3 file
	   high byte first */
	d = (width >> 8);
	fwrite( &d,1,1,dfFile );
	d = (width & 0xff);
	fwrite( &d,1,1,dfFile );
	d = (height >> 8);
	fwrite( &d,1,1,dfFile );
	d = (height & 0xff);
	fwrite( &d,1,1,dfFile );
	d = (nFiles >> 8);
	fwrite( &d,1,1,dfFile );
	d = (nFiles & 0xff);
	fwrite( &d,1,1,dfFile );

	fName = fileNames;
	for( f = 0; f < nFiles; f++ )
	{
		puts(fName);
		tgaFile = fopen( fName,"rb");
		fseek( tgaFile,18,SEEK_SET);
		for( p = 0; p < width*height; p++ )
		{
			/* read B,G,R convert to grey level */
			fread( &d,1,1,tgaFile );
			i = (double)d*0.11;
			fread( &d,1,1,tgaFile );
			i += (double)d*0.59;
			fread( &d,1,1,tgaFile );
			i += (double)d*0.30;
			d = (int)i;
			fwrite( &d,1,1,dfFile);
		}
		fclose(tgaFile);
		fName += longestName;
	}
	fclose(dfFile);

	return 0;
}