Adding FreeType2 support to PatchBox
It’s well overdue, but am finally getting around to adding font support to PatchBox. Rather than using bitmap based fonts, I thought it would be fun to use the font outlines and create proper 3D models. Here’s how it went:
Having extracted the glyph outline using FreeType2, let’s draw it with GL_LINES… ah…
GL_LINE_STRIP isn’t correct either…
Ah, good old GL_LINE_LOOP…
Initially, adding conic and cubic curves didn’t go quite as planned…
Better, but FreeType2 uses long’s to position data, resulting in the rather wobbly lines.
Converting to double’s does the trick nicely…
Now, lets’ fill the outlines using gluTesselate() – oh, FreeType2 uses NONZERO winding by default, whereas GLU uses ODD…
That’s looking better, but there’s still a problem…
Some characters are being drawn weirdly! Turns out to be a problem with my GLU_TESS_COMBINE_DATA routine. I’m using a custom vertex format, which I thought was what you returned from your combine callback, but no, you have to return an allocated GLdouble[ 3 ] and remember it so it can be freed later.
The finished result! All nice and smooth and stored away in vertex array ready for dumping to a VBO…
Next up will be creating a whole string, then multiple lines, then adding depth, colours, textures, etc!
