Loading OpenGL textures from FLTK

[FOSS Dev]

Hi my name is Dev. I want to know how i get a OpenGL texture from a raw .png, .jpeg, .bmp, etc file using FLTK.

I want the pixel data, number of components(RGB or RGBA), width and height of the raw image to make OpenGL texture.

Give me the most optimized way to do this.

Thanks

[Manolo]

You can get an Fl_RGB_Image object from a .png file with:

    https://www.fltk.org/doc-1.3/classFl__PNG__Image.html#a64b3f34f7b97784763802e39e2db3fc2

and similarly with .jpeg:

   https://www.fltk.org/doc-1.3/classFl__JPEG__Image.html#a8a12107808d6e86cd82b7bede8637aeb

and .bmp:

   https://www.fltk.org/doc-1.3/classFl__BMP__Image.html#a1abb2ebb6ca113fd03a967b66624c868

In all these cases, the resulting Fl_RGB_Image object, supposing you call it img, will tell you

if its RGB (img->d() == 3) or RGBA (img->d() == 4)and its width (img->w()) and height (img->h()).
In some cases, the row length is bigger than img->w()*img->d(). In that case img->ld() is != 0

and gives that length. Finally, you get the address of the first byte of the RGB or RGBA data

by img->array of type const unsigned char *. That should put you in the position to build a texture.

[FOSS Dev]

Thank you very much.

Here is the OpenGL texture class which uses FLTK: