View Full Version : Can I test wether a texture has been already loaded?

04-14-2002, 08:45 AM

My problem is this:
I'm reading in the paths to files containing textures (TGA-format), and then I'm loading the textures. The thing is, that sometimes I'm loading the same image (texture) twice or more, which of course is a waste of memory. Due to the structure of my program, it is not so easy just to test wether a certain path has already been used. Doing that would reduce the problem somewhat, but not entirely. So my question is this: Can I ask OpenGL wether a texture has already been loaded?

04-14-2002, 08:47 AM
Well, how would OpenGL know the filename?

04-14-2002, 08:53 AM
Yeah, I know it's a long shot, but I was just hoping, that it could be done in some clever way, since it would be the easiest solution in this case.

04-14-2002, 08:58 AM
Put this inside your texture loading implementation, and make sure you use MaybeLoadTexture() from the rest of your program:

static map<string,GLuint> loadedTextures;

static GLuint ReallyLoadTexture( char const * path )
// open TGA, generate texture ID, blah blah blah

GLuint MaybeLoadTexture( string path )
// you might want to make the string all lowercase first ...

// here, see if we already loaded it
map<string,GLuint>::iterator ptr( loadedTextures.find( path ) );
if( ptr != loadedTextures.end() ) {
return (*ptr).second;
GLuint ret = ReallyLoadTexture( path.c_str() );
loadedTextures[ path ] = ret;
return ret;

04-15-2002, 01:17 AM
To push things even further, it could happen that the same image is in two different files !

In this case, you could load the file and compare it to the already loaded textures byte by byte....


OK, just kidding ! http://www.opengl.org/discussion_boards/ubb/rolleyes.gif