public void getGlyphs (GlyphRun run, CharSequence str, int start, int end, Glyph lastGlyph) {
            if (packer != null) packer.setPackToTexture(true); // All glyphs added after this are packed directly to the texture.
            super.getGlyphs(run, str, start, end, lastGlyph);
            if (dirty) {
                dirty = false;
                packer.updateTextureRegions(regions, parameter.minFilter, parameter.magFilter, parameter.genMipMaps);
            }
        }
{@link BitmapFontData} used for fonts generated via the {@link FreeTypeFontGenerator}. The texture storing the glyphs is
held in memory, thus the {@link #getImagePaths()} and {@link #getFontFile()} methods will return null.
@author mzechner
@author Nathan Sweet
core/src/com/badlogic/gdx/graphics/g2d/freetype/FreeTypeFontGenerator.java