Re: [Plib-devel] Converting unsupported texture image file formats on the fly

[John F. F. <joh...@cy...>]

Done ... see change set 2127.

	- John


-----Original Message-----
From:	Paolo Leoncini 
Sent:	Monday, October 01, 2007 7:54 AM
To:	'PLIB Developers'
Subject:	[Plib-devel] Converting unsupported texture image file formats on	the fly

Dear friends,

In ssgLoadTexture.cxx the function

  bool ssgConvertTexture( char * fname_output, const char * fname_input )

is devoted to the subject task. As it is now it has two problems which I
propose here to overcome.

Line 248 SVN:

if ( ulFileExists ( fname_output ) )
  	return true; // found *.rgb-file

fname_output is the .rgb version of the fname_input file name with
unsupported image ext. (e.g. .jpg). The current code says that if the .rgb
version of the input file name does exist no conversion is needed - but it
could be older than that. Thus a test on the two files' modification time is
also needed.


Line 258 SVN:

  258 // ****** found original file. convert it. ******
  259 #ifdef UL_WIN32
  260   char command [ 1024 ] ;
  261 	sprintf(command, "imconvert -verbose %s sgi:%s", fname_input,
fname_output);
  262 	unsigned int ui = WinExec(command, SW_HIDE );
  263 	if ( ui < 32 )
  264 	{	ulSetError(UL_WARNING, "Couldn't convert texture '%s'. Did
you install ImageMagick?"
  265 		                       " You may also convert it manually to
'%s' and reload the model.",
  266
fname_input, fname_output);
  267 		return false;
  268 	}
  269 #else
  270 	ulSetError(UL_WARNING, "Converting textures not yet implemented
under Linux."
  271 		                     "You may convert '%s' manually to '%s'
and reload the model.",
  272
fname_input, fname_output);
  273   //sprintf(command, "-verbose %s sgi:%s", fname_input, fname_output);
  274 	//execlp ( "convert", "convert",  command, NULL ) ;
  275 
  276 #endif
  277 	return true;
  278 }

Under UL_WIN32 the WinExec function spawn a separate process and allows the
calling program to continue, so that the latter could proceed using the
(supposedly converted) image file w/o waiting for it to be actually
generated.
Furthermore it is not supported elsewhere than under Win32.
I propose to use the simpler and widely supported system() function, which
is blocking, and to test the existance of the output file as success
conformation.

The modified code for fixing both problems in ssgLoadTexture.cxx is reported
in the following.


#include <sys/stat.h>

int fileMTimeCmp( const char *fname_input, const char *fname_output )
// Compare the two input file names against their modification time
// -1: fname_input newer than fname_output
//  1: fname_input older than fname_output
//  0: stat error
{
	struct _stat buffer_in, buffer_out;
#ifdef UL_WIN32
#define stat _stat
#endif
	if ( stat( fname_input, &buffer_in ) == 0 && stat( fname_output,
&buffer_out ) == 0 )
		return buffer_in.st_mtime > buffer_out.st_mtime ? -1 : 1;
	else
		return 0;
}


bool ssgConvertTexture( char * fname_output, const char * fname_input ) 
// converts file to .rgb (Silicon Graphics) format
// returns true if the file has been converted to rgb, or already exists as
rgb
// if it returns false, then it has already output an error message
{
	char *extension ;

	strcpy( fname_output, fname_input); // copy so that a) there is
enough room for .rgb and b) we don't change the buffer of fname_input
	extension = strrchr(fname_output, '.');
	if ( extension == NULL )
	{
		ulSetError(UL_WARNING, "There is no extension in the texture
'%s'.", fname_input);
		return false; // no extension -> give up
	}
	extension[1] = 'r';
	extension[2] = 'g';
	extension[3] = 'b';
	extension[4] = 0;

	// look for original, non-rgb - file
	if ( !ulFileExists ( fname_input ) )
	{
		ulSetError(UL_WARNING, "Can't find the texture file '%s'.",
fname_input);
		return false; // no input file => we can't convert it
	}

	if ( ulFileExists ( fname_output ) && fileMTimeCmp( fname_input,
fname_output ) != -1 )
		return true; // found *.rgb-file, and it's newer than
fname_input, so no conversion is needed

	// ****** found original file. convert it. ******
	char command [ 1024 ] ;
	char *conv_cmd = 
#ifdef UL_WIN32
		"imconvert";
#else
		"convert";
#endif
	sprintf(command, "%s -verbose %s sgi:%s", conv_cmd, fname_input,
fname_output);
	if ( system( command ) < 0 || !ulFileExists ( fname_output ) )
	{	ulSetError(UL_WARNING, "Couldn't convert texture '%s'. Did
you install ImageMagick?"
		                       " You may also convert it manually to
'%s' and reload the model.", 
	
fname_input, fname_output);
		return false;
	}

	return true;
}

fileMTimeCmp could, of course, become an additional ul file utility (other
OS-es please check the stat compatibility on non Win32 systems, but the
Win32 _stat should be POSIX-compliant).

Paolo Leoncini


-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2005.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
plib-devel mailing list
pli...@li...
https://lists.sourceforge.net/lists/listinfo/plib-devel